worden

explanation blue bibcodes open ADS page with paths to full text

Author name code: worden
ADS astronomy entries on 2022-09-14
author:"Worden, Simon P." OR author:"Worden, Pete"

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Title: Venus Life Finder Missions Motivation and Summary
Authors: Seager, Sara; Petkowski, Janusz J.; Carr, Christopher E.;
Grinspoon, David H.; Ehlmann, Bethany L.; Saikia, Sarag J.; Agrawal,
Rachana; Buchanan, Weston P.; Weber, Monika U.; French, Richard;
Klupar, Pete; Worden, Simon P.; Baumgardner, Darrel
2022arXiv220805570S Altcode:
Finding evidence of extraterrestrial life would be one of the most
profound scientific discoveries ever made, advancing humanity into a
new epoch of cosmic awareness. The Venus Life Finder (VLF) missions
feature a series of three direct atmospheric probes designed to assess
the habitability of the Venusian clouds and search for signs of life
and life itself. The VLF missions are an astrobiology-focused set of
missions, and the first two out of three can be launched quickly and
at a relatively low cost. The mission concepts come out of an 18-month
study by an MIT-led worldwide consortium.

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Title: Benefit-Sharing as Investment Protection for Space Resource
Utilization
Authors: Bohacek, Petr; Worden, Simon P.; Grattan, Kyran
2022NewSp..10..127B Altcode:
No abstract at ADS

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Title: Searching for Broadband Pulsed Beacons from 1883 Stars Using
Neural Networks
Authors: Gajjar, Vishal; LeDuc, Dominic; Chen, Jiani; Siemion, Andrew
P. V.; Sheikh, Sofia Z.; Brzycki, Bryan; Croft, Steve; Czech, Daniel;
DeBoer, David; DeMarines, Julia; Drew, Jamie; Isaacson, Howard; Lacki,
Brian C.; Lebofsky, Matt; MacMahon, David H. E.; Ng, Cherry; de Pater,
Imke; Perez, Karen I.; Price, Danny C.; Suresh, Akshay; Webb, Claire;
Worden, S. Pete
2022ApJ...932...81G Altcode: 2022arXiv220502964G
The search for extraterrestrial intelligence at radio frequencies
has largely been focused on continuous-wave narrowband signals. We
demonstrate that broadband pulsed beacons are energetically efficient
compared to narrowband beacons over longer operational timescales. Here,
we report the first extensive survey searching for such broadband pulsed
beacons toward 1883 stars as a part of the Breakthrough Listen's search
for advanced intelligent life. We conducted 233 hr of deep observations
across 4-8 GHz using the Robert C. Byrd Green Bank Telescope and
searched for three different classes of signals with artificial
(or negative) dispersion. We report a detailed search-leveraging
a convolutional neural network classifier on high-performance
GPUs-deployed for the very first time in a large-scale search for
signals from extraterrestrial intelligence. Due to the absence of
any signal-of-interest from our survey, we place a constraint on
the existence of broadband pulsed beacons in our solar neighborhood:
≲1 in 1000 stars have transmitter power densities ≳105
W Hz-1 repeating ≤500 s at these frequencies.

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Title: The Breakthrough Listen Search for Intelligent Life:
Technosignature Search of Transiting TESS Targets of Interest
Authors: Franz, Noah; Croft, Steve; Siemion, Andrew P. V.; Traas,
Raffy; Brzycki, Bryan; Gajjar, Vishal; Isaacson, Howard; Lebofsky,
Matthew; MacMahon, David H. E.; Price, Danny C.; Sheikh, Sofia Z.;
DeMarines, Julia; Drew, Jamie; Worden, S. Pete
2022AJ....163..104F Altcode: 2022arXiv220100918F
The Breakthrough Listen (BL) Initiative, as part of its larger mission,
is performing the most thorough technosignature search of nearby
stars. Additionally, BL is collaborating with scientists working on
NASA's Transiting Exoplanet Survey Satellite (TESS) to examine TESS
Targets of Interest (TOIs) for technosignatures. Here, we present a
1-11 GHz radio technosignature search of 61 TESS TOIs that were in
transit during their BL observation at the Robert C. Byrd Green Bank
Telescope. We performed a narrowband Doppler drift search with a minimum
S/N threshold of 10 across a drift rate range of ±4 Hz s-1
with a resolution of 3 Hz. We removed radio frequency interference by
comparing signals across cadences of target sources. After interference
removal, there are no remaining events in our survey, and therefore
no technosignature signals of interest detected in this work. This
null result implies that at L, S, C, and X bands, fewer than 52%,
20%, 16%, and 15%, respectively, of TESS TOIs possess a transmitter
with an equivalent isotropic radiated power greater than a few times
1014 W.

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Title: The first deep-learning search for radio technosignatures
from 820 nearby stars
Authors: Ma, Xiangyuan; Ng, Cherry; Rizk, Leandro; Croft, Steve;
Siemion, Andrew; Brzycki, Bryan; Isaacson, Howard; Drew, Jamie;
Worden, S. Pete; Sheikh, Sofia Z.; de Pater, Imke; Gajjar, Vishal;
Czech, Daniel; Lebofsky, Matt; John, Hoang; MacMahon, David; Price,
Danny; Breakthrough Listen Team Team
2022APS..APRB09008M Altcode:
The goal of the Search for Extraterrestrial Intelligence (SETI) is to
quantify the prevalence of technological life beyond Earth via their
“technosignatures". One theorized technosignature is narrowband Doppler
drifting radio signals. The principal challenge in conducting SETI in
the radio domain is developing a generalized technique to reject human
radio frequency interference (RFI) that dominates the features across
the band in searches for technosignatures. Here, we will present the
first comprehensive deep-learning-based technosignature search to date,
returning 8 promising ETI signals-of-interest for re-observation as part
of the Breakthrough Listen initiative. The search comprises 820 unique
targets observed with the Robert C. Byrd Green Bank Telescope, totaling
over 480hr of on-sky data. We implement a novel beta-Convolutional
Variational Autoencoder with an embedded discriminator combined with
Random Forest Decision Trees to classify technosignature signals of
interest in a semi-unsupervised manner. We compare our results with
prior classical techniques on the same dataset and conclude that our
algorithm returns more convincing signals of interest with a manageable
false positive rate. This novel approach presents itself as a leading
solution in accelerating SETI and other transient research into the
new age of data-driven astronomy. The project was supported by
the Laidlaw foundation which has funded this project as part of the
undergraduate research and leadership funding initiative.

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Title: One of Everything: The Breakthrough Listen Exotica Catalog
Authors: Lacki, Brian C.; Brzycki, Bryan; Croft, Steve; Czech, Daniel;
DeBoer, David; DeMarines, Julia; Gajjar, Vishal; Isaacson, Howard;
Lebofsky, Matt; MacMahon, David H. E.; Price, Danny C.; Sheikh,
Sofia Z.; Siemion, Andrew P. V.; Drew, Jamie; Worden, S. Pete
2021ApJS..257...42L Altcode: 2020arXiv200611304L
We present Breakthrough Listen's Exotica Catalog as the centerpiece of
our efforts to expand the diversity of targets surveyed in the Search
for Extraterrestrial Intelligence (SETI). As motivation, we introduce
the concept of survey breadth, the diversity of objects observed
during a program. Several reasons for pursuing a broad program are
given, including increasing the chance of a positive result in SETI,
commensal astrophysics, and characterizing systematics. The Exotica
Catalog is a 963 entry collection of 816 distinct targets intended to
include "one of everything" in astronomy. It contains four samples:
the Prototype sample, with an archetype of every known major type of
nontransient celestial object; the Superlative sample of objects,
with the most extreme properties; the Anomaly sample of enigmatic
targets that are in some way unexplained; and the Control sample,
with sources not expected to produce positive results. As far as we
are aware, this is the first object list in recent times with the
purpose of spanning the breadth of astrophysics. We share it with the
community in hopes that it can guide treasury surveys and as a general
reference work. Accompanying the catalog is an extensive discussion
of the classification of objects and a new classification system for
anomalies. Extensive notes on the objects in the catalog are available
online. We discuss how we intend to proceed with observations in the
catalog, contrast it with our extant Exotica efforts, and suggest how
similar tactics may be applied to other programs.

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Title: Venus Life Finder Mission Study
Authors: Seager, Sara; Petkowski, Janusz J.; Carr, Christopher E.;
Grinspoon, David; Ehlmann, Bethany; Saikia, Sarag J.; Agrawal, Rachana;
Buchanan, Weston; Weber, Monika U.; French, Richard; Klupar, Pete;
Worden, Simon P.
2021arXiv211205153S Altcode:
The Venus Life Finder Missions are a series of focused astrobiology
mission concepts to search for habitability, signs of life, and life
itself in the Venus atmosphere. While people have speculated on
life in the Venus clouds for decades, we are now able to act with
cost-effective and highly-focused missions. A major motivation are
unexplained atmospheric chemical anomalies, including the "mysterious
UV-absorber", tens of ppm O$_2$, SO$_2$ and H$_2$O vertical abundance
profiles, the possible presence of PH$_3$ and NH$_3$, and the
unknown composition of Mode 3 cloud particles. These anomalies,
which have lingered for decades, might be tied to habitability and
life's activities or be indicative of unknown chemistry itself worth
exploring. Our proposed series of VLF missions aim to study Venus'
cloud particles and to continue where the pioneering in situ probe
missions from nearly four decades ago left off. The world is poised
on the brink of a revolution in space science. Our goal is not to
supplant any other efforts but to take advantage of an opportunity
for high-risk, high-reward science, which stands to possibly answer
one of the greatest scientific mysteries of all, and in the process
pioneer a new model of private/public partnership in space exploration.

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Title: No Redetections of blc1 in 39 hr of Reobservation Campaigns
of Proxima Centauri
Authors: Sheikh, Sofia Z.; Smith, Shane; Price, Danny; Lebofsky,
Matt; Siemion, Andrew; Cordes, James M.; Gajjar, Vishal; Drew, Jamie;
Worden, S. Pete
2021RNAAS...5..248S Altcode:
In 2019 April, radio observations of Proxima Centauri were performed
with the Ultra-Wideband Low Receiver on the Parkes Telescope. A
narrowband radio search of these data revealed a technosignature
signal-of-interest reported as "blc1" at 982.002 MHz. After the initial
discovery of blc1 in the data in 2020 October, we performed a series
of reobservations over the next 6 months, totaling 39 hr of on-sky
time. We do not redetect blc1, or find any other signals-of-interest,
within ±1 MHz of 982.002 MHz in this data set. Taken in context,
this null result implies that blc1 was transient radio frequency
interference, makes it less consistent with a periodic transmission,
and makes it less consistent with interstellar scintillation.

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Title: A radio technosignature search towards Proxima Centauri
resulting in a signal of interest
Authors: Smith, Shane; Price, Danny C.; Sheikh, Sofia Z.; Czech,
Daniel J.; Croft, Steve; DeBoer, David; Gajjar, Vishal; Isaacson,
Howard; Lacki, Brian C.; Lebofsky, Matt; MacMahon, David H. E.; Ng,
Cherry; Perez, Karen I.; Siemion, Andrew P. V.; Webb, Claire Isabel;
Drew, Jamie; Worden, S. Pete; Zic, Andrew
2021NatAs...5.1148S Altcode: 2021NatAs.tmp..203S; 2021arXiv211108007S
The detection of life beyond Earth is an ongoing scientific pursuit,
with profound implications. One approach, known as the search for
extraterrestrial intelligence (SETI), seeks to find engineered signals
(`technosignatures') that indicate the existence of technologically
capable life beyond Earth. Here, we report on the detection of a
narrowband signal of interest at ~982 MHz, recorded during observations
towards Proxima Centauri with the Parkes Murriyang radio telescope. This
signal, BLC1, has characteristics broadly consistent with hypothesized
technosignatures and is one of the most compelling candidates to
date. Analysis of BLC1—which we ultimately attribute to being an
unusual but locally generated form of interference—is provided in
a companion paper. Nevertheless, our observations of Proxima Centauri
are a particularly sensitive search for radio technosignatures towards
a stellar target.

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Title: Analysis of the Breakthrough Listen signal of interest blc1
with a technosignature verification framework
Authors: Sheikh, Sofia Z.; Smith, Shane; Price, Danny C.; DeBoer,
David; Lacki, Brian C.; Czech, Daniel J.; Croft, Steve; Gajjar, Vishal;
Isaacson, Howard; Lebofsky, Matt; MacMahon, David H. E.; Ng, Cherry;
Perez, Karen I.; Siemion, Andrew P. V.; Webb, Claire Isabel; Zic,
Andrew; Drew, Jamie; Worden, S. Pete
2021NatAs...5.1153S Altcode: 2021arXiv211106350S; 2021NatAs.tmp..206S
The aim of the search for extraterrestrial intelligence (SETI)
is to find technologically capable life beyond Earth through their
technosignatures. On 2019 April 29, the Breakthrough Listen SETI
project observed Proxima Centauri with the Parkes `Murriyang' radio
telescope. These data contained a narrowband signal with characteristics
broadly consistent with a technosignature near 982 MHz (`blc1'). Here
we present a procedure for the analysis of potential technosignatures,
in the context of the ubiquity of human-generated radio interference,
which we apply to blc1. Using this procedure, we find that blc1 is
not an extraterrestrial technosignature, but rather an electronically
drifting intermodulation product of local, time-varying interferers
aligned with the observing cadence. We find dozens of instances of
radio interference with similar morphologies to blc1 at frequencies
harmonically related to common clock oscillators. These complex
intermodulation products highlight the necessity for detailed follow-up
of any signal of interest using a procedure such as the one outlined
in this work.

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Title: The Breakthrough Listen Search for Intelligent Life: Searching
for Technosignatures in Observations of TESS Targets of Interest
Authors: Traas, Raffy; Croft, Steve; Gajjar, Vishal; Isaacson,
Howard; Lebofsky, Matt; MacMahon, David H. E.; Perez, Karen; Price,
Danny C.; Sheikh, Sofia; Siemion, Andrew P. V.; Smith, Shane; Drew,
Jamie; Worden, S. Pete
2021AJ....161..286T Altcode: 2021arXiv210111137T
Exoplanetary systems are prime targets for the Search for
Extraterrestrial Intelligence (SETI). With the recent uptick in
the identification of candidate and confirmed exoplanets through
the work of missions like the Transiting Exoplanet Survey Satellite
(TESS), we are beginning to understand that Earth-like planets are
common. In this work, we extend the Breakthrough Listen (BL) search
for extraterrestrial intelligence to include targeted searches of stars
identified by TESS as potential exoplanet hosts. We report on $113$ 30
minute cadence observations collected for 28 targets selected from the
TESS Input Catalog from among those identified as containing signatures
of transiting planets. The targets were searched for narrowband signals
from 1 to 11 GHz using the turboSETI pipeline architecture modified for
compatibility with the Google Cloud environment. Data were searched for
drift rates of ±4 Hz s-1 above a minimum signal-to-noise
threshold of 10, following the parameters of previous searches conducted
by Price et al. and Enriquez et al. The observations presented in
this work establish some of the deepest limits to date over such a
wide band (1-11 GHz) for life beyond Earth. We determine that fewer
than 12.72% of the observed targets possess transmitters operating at
these frequencies with an equivalent isotropic radiated power greater
than our derived threshold of $4.9\times {10}^{14}\,{\rm{W}}$ .

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Title: Expanded Capability of the Breakthrough Listen Parkes Data
Recorder for Observations with the UWL Receiver
Authors: Price, Danny C.; MacMahon, David H. E.; Lebofsky, Matt;
Isaacson, Howard; Sheikh, Sofia; Czech, Daniel; Gajjar, Vishal;
Siemion, Andrew; Drew, Jamie; Worden, S. Pete; Green, James A.; Craig,
Daniel; Amy, Shaun
2021RNAAS...5..114P Altcode:
The ultra-wideband low (UWL) receiver is a new feed for the Parkes
telescope, which covers the combined bandwidth of four previously
installed receivers. In order to use the UWL for technosignature
observations, several updates and upgrades were made on the Breakthrough
Listen Parkes Data Recorder (BLPDR). This Research Note summarizes BLPDR
hardware upgrades and new capacity for technosignature observations
with the UWL receiver.

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Title: Lunar Opportunities for SETI
Authors: Michaud, Eric; Siemion, Andrew P. V.; Drew, Jamie; Worden,
S. Pete
2021BAAS...53d.369M Altcode: 2021psad.rept..369M
A radio telescope placed in lunar orbit, or on the surface of the Moon's
farside, could be of great value to the Search for Extraterrestrial
Intelligence (SETI). In this paper, we review existing literature
on Moon-based radio astronomy, discuss the benefits of lunar SETI,
and contrast possible mission concepts.

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Title: Re-analysis of Breakthrough Listen Observations of FRB 121102:
Polarization Properties of Eight New Spectrally Narrow Bursts
Authors: Faber, Jakob T.; Gajjar, Vishal; Siemion, Andrew P. V.;
Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew,
Jamie; Isaacson, Howard; Lacki, Brian C.; Lebofsky, Matt; MacMahon,
David H. E.; Ng, Cherry; Pater, Imke de; Price, Danny C.; Sheikh,
Sofia Z.; Webb, Claire; Worden, S. Pete
2021RNAAS...5...17F Altcode: 2021arXiv210105172F
We report polarization properties for eight narrowband bursts from
FRB 121102 that have been re-detected in a high-frequency (4-8
GHz) Breakthrough Listen observation with the Green Bank Telescope,
originally taken on 2017 August 26. The bursts were found to exhibit
nearly 100% linear polarization, Faraday rotation measures bordering 9.3
× 104 rad m-2, and stable polarization position
angles, all of which agree with burst properties previously reported
for FRB 121102 at the same epoch. We confirm that these detections are
indeed physical bursts with limited spectral occupancies and further
support the use of sub-banded search techniques in FRB detection.

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Title: Narrow-band Signal Localization for SETI on Noisy Synthetic
Spectrogram Data
Authors: Brzycki, Bryan; Siemion, Andrew P. V.; Croft, Steve; Czech,
Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Gajjar, Vishal;
Isaacson, Howard; Lacki, Brian; Lebofsky, Matthew; MacMahon, David
H. E.; de Pater, Imke; Price, Danny C.; Worden, S. Pete
2020PASP..132k4501B Altcode: 2020arXiv200604362B
As it stands today, the search for extraterrestrial intelligence is
highly dependent on our ability to detect interesting candidate signals,
or technosignatures, in radio telescope observations and distinguish
these from human radio frequency interference (RFI). Current signal
search pipelines look for signals in spectrograms of intensity as a
function of time and frequency (which can be thought of as images),
but tend to do poorly in identifying multiple signals in a single data
frame. This is especially apparent when there are dim signals in the
same frame as bright, high signal-to-noise ratio (S/N) signals. In this
work, we approach this problem using convolutional neural networks
(CNN) as a computationally efficient method for localizing signals
in synthetic observations resembling data collected by Breakthrough
Listen using the Green Bank Telescope. We generate two synthetic data
sets, the first with exactly one signal at various S/N levels and the
second with exactly two signals, one of which represents RFI. We find
that a residual CNN with strided convolutions and using multiple image
normalizations as input outperforms a more basic CNN with max pooling
trained on inputs with only one normalization. Training each model on
a smaller subset of the training data at higher S/N levels results
in a significant increase in model performance, reducing root mean
square errors by at least a factor of 3 at an S/N of 25 dB. Although
each model produces outliers with significant error, these results
demonstrate that using CNNs to analyze signal location is promising,
especially in image frames that are crowded with multiple signals.

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Title: Lunar Opportunities for SETI
Authors: Michaud, Eric J.; Siemion, Andrew P. V.; Drew, Jamie; Worden,
S. Pete
2020arXiv200912689M Altcode:
A radio telescope placed in lunar orbit, or on the surface of the Moon's
farside, could be of great value to the Search for Extraterrestrial
Intelligence (SETI). The advantage of such a telescope is that it
would be shielded by the body of the Moon from terrestrial sources of
radio frequency interference (RFI). While RFI can be identified and
ignored by other fields of radio astronomy, the possible spectral
similarity between human and alien-generated radio emission makes
the abundance of artificial radio emission on and around the Earth a
significant complicating factor for SETI. A Moon-based telescope would
avoid this challenge. In this paper, we review existing literature
on Moon-based radio astronomy, discuss the benefits of lunar SETI,
contrast possible surface- and orbit-based telescope designs, and argue
that such initiatives are scientifically feasible, both technically
and financially, within the next decade.

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Title: Breakthrough Listen Search for Technosignatures toward the
Kepler-160 System
Authors: Perez, Karen; Brzycki, Bryan; Gajjar, Vishal; Isaacson,
Howard; Siemion, Andrew; Croft, Steve; DeBoer, David; Lebofsky, Matt;
MacMahon, David H. E.; Price, Danny C.; Sheikh, Sofia; Drew, Jamie;
Worden, S. Pete
2020RNAAS...4...97P Altcode: 2020arXiv200613789P
We have conducted a search for artificial radio emission associated
with the Kepler-160 system following the report of the discovery of
the Earth-like planet candidate KOI-456.04 on 2020 June 4 (Heller
et al. 2020). Our search targeted both narrowband (2.97 Hz) drifting
(±4 Hz s-1) and wideband pulsed (5 ms at all bandwidths)
artificially dispersed technosignatures using the turboSETI (Enriquez
et al. 2017) and SPANDAK (V. Gajjar et al. 2020, in preparation)
pipelines, respectively, from 1 to 8 GHz. No candidates were identified
above an upper limit Equivalent Isotropic Radiated Power of 5.9 ×
1014 W for narrowband emission and 7.3 × 1012
W for wideband emission. Here we briefly describe our observations
and data reduction procedure.

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Title: Exploration of the outer solar system with fast and small
sailcraft
Authors: Turyshev, Slava G.; Klupar, Peter; Loeb, Abraham; Manchester,
Zachary; Parkin, Kevin; Witten, Edward; Worden, S. Pete
2020arXiv200512336T Altcode:
Two new interplanetary technologies have advanced in the past decade
to the point where they may enable exciting, affordable missions
that reach further and faster deep into the outer regions of our
solar system: (i) small and capable interplanetary spacecraft and
(ii) light-driven sails. Combination of these two technologies could
drastically reduce travel times within the solar system. We discuss
a new paradigm that involves small and fast moving sailcraft that
could enable exploration of distant regions of the solar system much
sooner and faster than previously considered. We present some of the
exciting science objectives for these miniaturized intelligent space
systems that could lead to transformational advancements in the space
sciences in the coming decade.

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Title: Opportunities to search for extraterrestrial intelligence
with the FAST
Authors: Li, Di; Gajjar, Vishal; Wang, Pei; Siemion, Andrew; Zhang,
Zhi-Song; Zhang, Hai-Yan; Yue, You-Ling; Zhu, Yan; Jin, Cheng-Jin;
Li, Shi-Yu; Berger, Sabrina; Brzycki, Bryan; Cobb, Jeff; Croft,
Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie;
Emilio Enriquez, J.; Gizani, Nectaria; Korpela, Eric J.; Isaacson,
Howard; Lebofsky, Matthew; Lacki, Brian; MacMahon, David H. E.; Nanez,
Morgan; Niu, Chen-Hui; Pei, Xin; Price, Danny C.; Werthimer, Dan;
Worden, Pete; Gerry Zhang, Yunfan; Zhang, Tong-Jie; FAST Collaboration
2020RAA....20...78L Altcode:
The discovery of ubiquitous habitable extrasolar planets, combined
with revolutionary advances in instrumentation and observational
capabilities, has ushered in a renaissance in the search for
extraterrestrial intelligence (SETI). Large scale SETI activities
are now underway at numerous international facilities. The
Five-hundred-meter Aperture Spherical radio Telescope (FAST) is
the largest single-aperture radio telescope in the world, and is
well positioned to conduct sensitive searches for radio emission
indicative of exo-intelligence. SETI is one of the five key science
goals specified in the original FAST project plan. A collaboration with
the Breakthrough Listen Initiative was initiated in 2016 with a joint
statement signed both by Dr. Jun Yan, the then director of National
Astronomical Observatories, Chinese Academy of Sciences (NAOC), and
Dr. Peter Worden, Chairman of the Breakthrough Prize Foundation. In this
paper, we highlight some of the unique features of FAST that will allow
for novel SETI observations. We identify and describe three different
signal types indicative of a technological source, namely, narrow
band, wide-band artificially dispersed and modulated signals. Here, we
propose observations with FAST to achieve sensitivities never before
explored. For nearby exoplanets, such as TESS targets, FAST will be
sensitive to an EIRP of 1.9 × 1011 W, well within the reach
of current human technology. For the Andromeda Galaxy, FAST will be able
to detect any Kardashev type II or more advanced civilization there.

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Title: The Breakthrough Listen Search for Intelligent Life:
Observations of 1327 Nearby Stars Over 1.10-3.45 GHz
Authors: Price, Danny C.; Enriquez, J. Emilio; Brzycki, Bryan; Croft,
Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Foster, Griffin;
Gajjar, Vishal; Gizani, Nectaria; Hellbourg, Greg; Isaacson, Howard;
Lacki, Brian; Lebofsky, Matt; MacMahon, David H. E.; Pater, Imke de;
Siemion, Andrew P. V.; Werthimer, Dan; Green, James A.; Kaczmarek, Jane
F.; Maddalena, Ronald J.; Mader, Stacy; Drew, Jamie; Worden, S. Pete
2020AJ....159...86P Altcode: 2019arXiv190607750P
Breakthrough Listen (BL) is a 10 year initiative to search for
signatures of technologically capable life beyond Earth via radio
and optical observations of the local universe. A core part of the
BL program is a comprehensive survey of 1702 nearby stars at radio
wavelengths (1-10 GHz). Here, we report on observations with the 64 m
CSIRO Parkes radio telescope in New South Wales, Australia, and the 100
m Robert C. Byrd Green Bank radio telescope in West Virginia, USA. Over
2016 January to 2019 March, a sample of 1138 stars was observed at
Green Bank using the 1.10-1.90 GHz and 1.80-2.80 GHz receivers, and 189
stars were observed with Parkes over 2.60-3.45 GHz. We searched these
data for the presence of engineered signals with Doppler-acceleration
drift rates between ±4 Hz s-1. Here, we detail our data
analysis techniques and provide examples of detected events. After
excluding events with characteristics consistent with terrestrial radio
interference, we are left with zero candidates. That is, we find no
evidence of putative radio transmitters above $2.1\times {10}^{12}$ W,
and $9.1\times {10}^{12}$ W for Green Bank and Parkes observations,
respectively. These observations constitute the most comprehensive
search over 1.10-3.45 GHz for technosignatures to date. All data
products, totaling ∼219 TB, are available for download as part of
the first BL data release (DR1), as described in a companion paper.

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Title: Opportunities to Search for Extra-Terrestrial Intelligence
with the Five-hundred-meter Aperture Spherical radio Telescope
Authors: Li, Di; Gajjar, Vishal; Wang, Pei; Siemion, Andrew; Zhang,
Zhisong; Zhang, Haiyan; Yue, Youling; Zhu, Yan; Jin, Chengjin; Li,
Shiyu; Berger, Sabrina; Brzycki, Bryan; Cobb, Jeff; Croft, Steve;
Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Enriquez,
J. Emilio; Gizani, Nectaria; Korpela, Eric J.; Isaacson, Howard;
Lebofsky, Matthew; Lacki, Brian; MacMahon, David H. E.; Nanez,
Morgan; Niu, Chenhui; Pei, Xin; Price, Danny C.; Werthimer, Dan;
Worden, Pete; Zhang, Yunfan Gerry; Zhang, Tong-Jie; FAST Collaboration
2020arXiv200309639L Altcode:
The discovery of ubiquitous habitable extrasolar planets, combined
with revolutionary advances in instrumentation and observational
capabilities, has ushered in a renaissance in the search for
extra-terrestrial intelligence (SETI). Large scale SETI activities
are now underway at numerous international facilities. The
Five-hundred-meter Aperture Spherical radio Telescope (FAST)
is the largest single-aperture radio telescope in the world,
well positioned to conduct sensitive searches for radio emission
indicative of exo-intelligence. SETI is one of the five key science
goals specified in the original FAST project plan. A collaboration with
the Breakthrough Listen Initiative has been initiated in 2016 with
a joint statement signed both by Dr. Jun Yan, the then director of
the National Astronomical Observatories, Chinese Academy of Sciences
(NAOC), and Dr. Peter Worden, the Chairman of the Breakthrough Prize
Foundation. In this paper, we highlight some of the unique features
of FAST that will allow for novel SETI observations. We identify and
describe three different signal types indicative of a technological
source, namely, narrow-band, wide-band artificially dispersed, and
modulated signals. We here propose observations with FAST to achieve
sensitivities never before explored.

---------------------------------------------------------
Title: The Breakthrough Listen Search for Intelligent Life: Public
Data, Formats, Reduction, and Archiving
Authors: Lebofsky, Matthew; Croft, Steve; Siemion, Andrew P. V.;
Price, Danny C.; Enriquez, J. Emilio; Isaacson, Howard; MacMahon,
David H. E.; Anderson, David; Brzycki, Bryan; Cobb, Jeff; Czech,
Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Foster, Griffin;
Gajjar, Vishal; Gizani, Nectaria; Hellbourg, Greg; Korpela, Eric J.;
Lacki, Brian; Sheikh, Sofia; Werthimer, Dan; Worden, Pete; Yu, Alex;
Zhang, Yunfan Gerry
2019PASP..131l4505L Altcode: 2019arXiv190607391L
Breakthrough Listen is the most comprehensive and sensitive search for
extraterrestrial intelligence (SETI) to date, employing a collection
of international observational facilities including both radio and
optical telescopes. During the first three years of the Listen program,
thousands of targets have been observed with the Green Bank Telescope
(GBT), Parkes Telescope and Automated Planet Finder. At GBT and Parkes,
observations have been performed ranging from 700 MHz to 26 GHz, with
raw data volumes averaging over 1 PB day-1. A pseudo-real
time software spectroscopy suite is used to produce multi-resolution
spectrograms amounting to approximately 400 GB h-1
GHz-1 beam-1. For certain targets, raw baseband
voltage data is also preserved. Observations with the Automated Planet
Finder produce both two-dimensional and one-dimensional high-resolution
(R ∼ 105) echelle spectral data. Although the primary
purpose of Listen data acquisition is for SETI, a range of secondary
science has also been performed with these data, including studies of
fast radio bursts. Other current and potential research topics include
spectral line studies, searches for certain kinds of dark matter,
probes of interstellar scattering, pulsar searches, radio transient
searches and investigations of stellar activity. Listen data are also
being used in the development of algorithms, including machine-learning
approaches to modulation scheme classification and outlier detection,
that have wide applicability not just for astronomical research but for
a broad range of science and engineering. In this paper, we describe the
hardware and software pipeline used for collection, reduction, archival,
and public dissemination of Listen data. We describe the data formats
and tools, and present Breakthrough Listen Data Release 1.0 (BLDR 1.0),
a defined set of publicly available raw and reduced data totaling 1 PB.

---------------------------------------------------------
Title: Breakthrough Listen Follow-up of the Random Transiter (EPIC
249706694/HD 139139) with the Green Bank Telescope
Authors: Brzycki, Bryan; Siemion, Andrew; Croft, Steve; Czech, Daniel;
DeBoer, David; DeMarines, Julia; Drew, Jamie; Enriquez, J. Emilio;
Gajjar, Vishal; Gizani, Nectaria; Isaacson, Howard; Lacki, Brian;
Lebofsky, Matt; MacMahon, David H. E.; de Pater, Imke; Price, Danny
C.; Sheikh, Sofia; Webb, Claire; Worden, S. Pete
2019RNAAS...3..147B Altcode: 2019arXiv191003711B
The star EPIC 249706694 (HD 139139) was found to exhibit 28 transit-like
events over an 87 day period during the Kepler mission's K2 Campaign 15
(Rappaport et al. 2019). These events did not fall into an identifiable
pattern and could not be explained by a multitude of transit scenarios
explored by the authors. We conduct follow-up observations at C-band
frequencies with the Green Bank Telescope as part of the ongoing
Breakthrough Listen search for technosignatures. We search for narrow
band signals above a signal-to-noise threshold of 10 and with Doppler
drift rates within +-5 Hz/s. We detect no evidence of technosignatures
from EPIC 249706694 and derive an upper limit for the EIRP (Equivalent
Isotropic Radiated Power) of putative transmissions to be 10 TW.

---------------------------------------------------------
Title: The Breakthrough Listen Search for Extraterrestrial
Intelligence
Authors: Gajjar, Vishal; Siemion, Andrew; Croft, Steve; Brzycki, Bryan;
Burgay, Marta; Carozzi, Tobia; Concu, Raimondo; Czech, Daniel; DeBoer,
David; DeMarines, Julia; Drew, Jamie; Enriquez, J. Emilio; Fawcett,
James; Gallagher, Peter; Gerret, Michael; Gizani, Nectaria; Hellbourg,
Greg; Holder, Jamie; Isaacson, Howard; Kudale, Sanjay; Lacki, Brian;
Lebofsky, Matthew; Li, Di; MacMahon, David H. E.; McCauley, Joe;
Melis, Andrea; Molinari, Emilio; Murphy, Pearse; Perrodin, Delphine;
Pilia, Maura; Price, Danny C.; Webb, Claire; Werthimer, Dan; Williams,
David; Worden, Pete; Zarka, Philippe; Zhang, Yunfan Gerry
2019BAAS...51g.223G Altcode: 2019astro2020U.223G; 2019arXiv190705519G
In this white paper, we outline the status of the on-going observing
campaign with our primary and collaborative observing facilities, as
well as planned activities with these instruments over the next few
years with the Breakthrough Listen program for the technosignature
searches.

---------------------------------------------------------
Title: A fast radio burst with frequency-dependent polarization
detected during Breakthrough Listen observations
Authors: Price, D. C.; Foster, G.; Geyer, M.; van Straten, W.; Gajjar,
V.; Hellbourg, G.; Karastergiou, A.; Keane, E. F.; Siemion, A. P. V.;
Arcavi, I.; Bhat, R.; Caleb, M.; Chang, S. -W.; Croft, S.; DeBoer,
D.; de Pater, I.; Drew, J.; Enriquez, J. E.; Farah, W.; Gizani, N.;
Green, J. A.; Isaacson, H.; Hickish, J.; Jameson, A.; Lebofsky, M.;
MacMahon, D. H. E.; Möller, A.; Onken, C. A.; Petroff, E.; Werthimer,
D.; Wolf, C.; Worden, S. P.; Zhang, Y. G.
2019MNRAS.486.3636P Altcode: 2019MNRAS.tmp..950P; 2019arXiv190107412P
Here, we report on the detection and verification of fast radio burst
FRB 180301, which occurred on UTC 2018 March 1 during the Breakthrough
Listen observations with the Parkes telescope. Full-polarization voltage
data of the detection were captured - a first for non-repeating FRBs
- allowing for coherent de-dispersion and additional verification
tests. The coherently de-dispersed dynamic spectrum of FRB 180301
shows complex, polarized frequency structure over a small fractional
bandwidth. As FRB 180301 was detected close to the geosynchronous
satellite band during a time of known 1-2 GHz satellite transmissions,
we consider whether the burst was due to radio interference emitted
or reflected from an orbiting object. Based on the pre-ponderance of
our verification tests, we cannot conclusively determine FRB 180301
to be either astrophysical or anthropogenic in origin.

---------------------------------------------------------
Title: Breakthrough Listen Observations of Asteroid (514107) 2015
BZ509 with the Parkes Radio Telescope
Authors: Price, Danny C.; Croft, Steve; DeBoer, David; Drew, Jamie;
Enriquez, J. Emilio; Foster, Griffin; Gajjar, Vishal; Gizani, Nectaria;
Hellbourg, Greg; Isaacson, Howard; Lebofsky, Matt; MacMahon, David
H. E.; de Pater, Imke; Siemion, Andrew; Worden, S. Pete; Zhang,
Yufan Gerry
2019RNAAS...3...19P Altcode: 2019RNAAS...3a..19P
No abstract at ADS

---------------------------------------------------------
Title: Philanthropic Space Science: The Breakthrough Initiatives
Authors: Worden, Simon P.; Drew, Jamie; Klupar, Peter
2018NewSp...6..262W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: mSTAR: Testing Lorentz invariance in a low Earth orbit with
high performance optical frequency standards
Authors: Saraf, Shailendhar; Buchman, Sasha; Cutler, Grant D.;
Lipa, John; Tan, Si; Byer, Robert; Schuldt, Thilo; Dittus, HansjöRg
Braxmaier, Claus; Peters, Achim; DöRingshoff, Klaus; Hanson, John;
Jaroux, Belgacem; Worden, Simon P.; Alfauwaz, Abdul; Alhussien,
Abdulaziz; Alsuwaidan, Badr; Saud, Turki Al; Gürlebeck, Norman;
Herrmann, Sven; LäMmerzahl, Claus; Johann, Ulrich
2018mgm..conf.3591S Altcode:
The mini Space Time Asymmetry Research (mSTAR) is a proposed space
mission to perform an advanced Kennedy-Thorndike (KT) test of Special
Relativity using the large and rapid velocity modulation available in
low Earth orbit (LEO). The mission goal is to test special relativity
by performing a clock-clock comparison experiment in LEO, thereby
testing the boost dependence of the speed of light. Clocks with
stabilities better than 10-15 level at orbit time will
allow the KT coefficient to be measured with up to two orders of
magnitude higher accuracy than current ground-based experiments, with
an additional factor of 10 possible using more advanced technology. In
the current baseline, mSTAR utilizes an absolute frequency reference
based on modulation transfer spectroscopy of molecular iodine and
a length-reference based on a high-finesse ultra-stable optical
cavity. Current efforts aim at a space compatible design of the two
clocks and improving the long-term stability of the cavity reference. In
a recently completed Phase A study, the feasibility of accommodating
the mSTAR experiment on a SaudiSat 4 bus was investigated.

---------------------------------------------------------
Title: Breakthrough Listen - A New Search for Life in the Universe
Authors: Worden, Pete
2016iac..conf34378W Altcode:
On July 20, 2015 Yuri Milner and Stephen Hawking announced a new set of
scientific initiatives - a SETI search called Breakthrough Listen and a
contest to devise potential messages in response to a detection entitled
Breakthrough Message. These are the first of several privately-funded
Breakthrough Initiatives, designed to answer the fundamental science
questions surrounding the origin, extent and nature of life in the
universe. The initiatives are managed by the Breakthrough Prize
Foundation. With Breakthrough Listen, Radio SETI observations have
begun at the Green Bank Radio Telescope (GBT) and optical SETI at the
Lick Observatory Automated Planet Finder (APF). Observations will soon
commence at the CSIRO Parkes Radio Telescope. Other SETI instruments
and observations are under consideration. In addition, several other
initiatives are under development including an expanded search for
life in the universe.

---------------------------------------------------------
Title: Gravity Probe B data analysis: II. Science data and their
handling prior to the final analysis
Authors: Silbergleit, A. S.; Conklin, J. W.; Heifetz, M. I.; Holmes,
T.; Li, J.; Mandel, I.; Solomonik, V. G.; Stahl, K.; Worden, P. W.,
Jr.; Everitt, C. W. F.; Adams, M.; Berberian, J. E.; Bencze, W.;
Clarke, B.; Al-Jadaan, A.; Keiser, G. M.; Kozaczuk, J. A.; Al-Meshari,
M.; Muhlfelder, B.; Salomon, M.; Santiago, D. I.; Al-Suwaidan, B.;
Turneaure, J. P.; Wade, J.
2015CQGra..32v4019S Altcode:
The results of the Gravity Probe B relativity science mission published
in Everitt et al (2011 Phys. Rev. Lett. 106 221101) required a rather
sophisticated analysis of experimental data due to several unexpected
complications discovered on-orbit. We give a detailed description of
the Gravity Probe B data reduction. In the first paper (Silbergleit et
al Class. Quantum Grav. 22 224018) we derived the measurement models,
i.e., mathematical expressions for all the signals to analyze. In the
third paper (Conklin et al Class. Quantum Grav. 22 224020) we explain
the estimation algorithms and their program implementation, and discuss
the experiment results obtained through data reduction. This paper
deals with the science data preparation for the main analysis yielding
the relativistic drift estimates.

---------------------------------------------------------
Title: Gravity Probe B data analysis: I. Coordinate frames and
analysis models
Authors: Silbergleit, A. S.; Keiser, G. M.; Turneaure, J. P.;
Conklin, J. W.; Everitt, C. W. F.; Heifetz, M. I.; Holmes, T.; Worden,
P. W., Jr.
2015CQGra..32v4018S Altcode:
Gravity Probe B (GP-B) was a cryogenic, space-based experiment
testing the geodetic and frame-dragging predictions of Einstein's
theory of general relativity (GR) by means of gyroscopes in Earth
orbit. This first of three data analysis papers reviews the GR
predictions and details the models that provide the framework for the
relativity analysis. In the second paper we describe the flight data
and their preprocessing. The third paper covers the algorithms and
software tools that fit the preprocessed flight data to the models
to give the experimental results published in Everitt et al (2011
Phys. Rev. Lett. 106 221101-4).

---------------------------------------------------------
Title: The Gravity Probe B test of general relativity
Authors: Everitt, C. W. F.; Muhlfelder, B.; DeBra, D. B.; Parkinson,
B. W.; Turneaure, J. P.; Silbergleit, A. S.; Acworth, E. B.; Adams,
M.; Adler, R.; Bencze, W. J.; Berberian, J. E.; Bernier, R. J.; Bower,
K. A.; Brumley, R. W.; Buchman, S.; Burns, K.; Clarke, B.; Conklin,
J. W.; Eglington, M. L.; Green, G.; Gutt, G.; Gwo, D. H.; Hanuschak,
G.; He, X.; Heifetz, M. I.; Hipkins, D. N.; Holmes, T. J.; Kahn,
R. A.; Keiser, G. M.; Kozaczuk, J. A.; Langenstein, T.; Li, J.; Lipa,
J. A.; Lockhart, J. M.; Luo, M.; Mandel, I.; Marcelja, F.; Mester,
J. C.; Ndili, A.; Ohshima, Y.; Overduin, J.; Salomon, M.; Santiago,
D. I.; Shestople, P.; Solomonik, V. G.; Stahl, K.; Taber, M.; Van
Patten, R. A.; Wang, S.; Wade, J. R.; Worden, P. W., Jr.; Bartel,
N.; Herman, L.; Lebach, D. E.; Ratner, M.; Ransom, R. R.; Shapiro,
I. I.; Small, H.; Stroozas, B.; Geveden, R.; Goebel, J. H.; Horack,
J.; Kolodziejczak, J.; Lyons, A. J.; Olivier, J.; Peters, P.; Smith,
M.; Till, W.; Wooten, L.; Reeve, W.; Anderson, M.; Bennett, N. R.;
Burns, K.; Dougherty, H.; Dulgov, P.; Frank, D.; Huff, L. W.; Katz,
R.; Kirschenbaum, J.; Mason, G.; Murray, D.; Parmley, R.; Ratner,
M. I.; Reynolds, G.; Rittmuller, P.; Schweiger, P. F.; Shehata, S.;
Triebes, K.; VandenBeukel, J.; Vassar, R.; Al-Saud, T.; Al-Jadaan,
A.; Al-Jibreen, H.; Al-Meshari, M.; Al-Suwaidan, B.
2015CQGra..32v4001E Altcode:
The Gravity Probe B mission provided two new quantitative tests of
Einstein's theory of gravity, general relativity (GR), by cryogenic
gyroscopes in Earth's orbit. Data from four gyroscopes gave a
geodetic drift-rate of -6601.8 ± 18.3 marc-s yr-1 and a
frame-dragging of -37.2 ± 7.2 marc-s yr-1, to be compared
with GR predictions of -6606.1 and -39.2 marc-s yr-1
(1 marc-s = 4.848 × 10-9 radians). The present paper
introduces the science, engineering, data analysis, and heritage of
Gravity Probe B, detailed in the accompanying 20 CQG papers.

---------------------------------------------------------
Title: Erratum: “Science With a Wide-Field UV Transient Explorer”
<A href="/abs/2014AJ....147...79S">(2014, AJ, 147, 79)</A>
Authors: Sagiv, I.; Gal-Yam, A.; Ofek, E. O.; Waxman, E.; Aharonson,
O.; Kulkarni, S. R.; Nakar, E.; Maoz, D.; Trakhtenbrot, B.; Gottesman,
O.; Phinney, E. S.; Topaz, J.; Beichman, C.; Murthy, J.; Worden, S. P.
2014AJ....148..138S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Interface Region Imaging Spectrograph (IRIS)
Authors: De Pontieu, B.; Title, A. M.; Lemen, J. R.; Kushner, G. D.;
Akin, D. J.; Allard, B.; Berger, T.; Boerner, P.; Cheung, M.; Chou,
C.; Drake, J. F.; Duncan, D. W.; Freeland, S.; Heyman, G. F.; Hoffman,
C.; Hurlburt, N. E.; Lindgren, R. W.; Mathur, D.; Rehse, R.; Sabolish,
D.; Seguin, R.; Schrijver, C. J.; Tarbell, T. D.; Wülser, J. -P.;
Wolfson, C. J.; Yanari, C.; Mudge, J.; Nguyen-Phuc, N.; Timmons,
R.; van Bezooijen, R.; Weingrod, I.; Brookner, R.; Butcher, G.;
Dougherty, B.; Eder, J.; Knagenhjelm, V.; Larsen, S.; Mansir, D.;
Phan, L.; Boyle, P.; Cheimets, P. N.; DeLuca, E. E.; Golub, L.;
Gates, R.; Hertz, E.; McKillop, S.; Park, S.; Perry, T.; Podgorski,
W. A.; Reeves, K.; Saar, S.; Testa, P.; Tian, H.; Weber, M.; Dunn, C.;
Eccles, S.; Jaeggli, S. A.; Kankelborg, C. C.; Mashburn, K.; Pust, N.;
Springer, L.; Carvalho, R.; Kleint, L.; Marmie, J.; Mazmanian, E.;
Pereira, T. M. D.; Sawyer, S.; Strong, J.; Worden, S. P.; Carlsson,
M.; Hansteen, V. H.; Leenaarts, J.; Wiesmann, M.; Aloise, J.; Chu,
K. -C.; Bush, R. I.; Scherrer, P. H.; Brekke, P.; Martinez-Sykora,
J.; Lites, B. W.; McIntosh, S. W.; Uitenbroek, H.; Okamoto, T. J.;
Gummin, M. A.; Auker, G.; Jerram, P.; Pool, P.; Waltham, N.
2014SoPh..289.2733D Altcode: 2014arXiv1401.2491D; 2014SoPh..tmp...25D
The Interface Region Imaging Spectrograph (IRIS) small explorer
spacecraft provides simultaneous spectra and images of the photosphere,
chromosphere, transition region, and corona with 0.33 - 0.4 arcsec
spatial resolution, two-second temporal resolution, and 1 km
s−1 velocity resolution over a field-of-view of up to
175 arcsec × 175 arcsec. IRIS was launched into a Sun-synchronous
orbit on 27 June 2013 using a Pegasus-XL rocket and consists of a
19-cm UV telescope that feeds a slit-based dual-bandpass imaging
spectrograph. IRIS obtains spectra in passbands from 1332 - 1358 Å,
1389 - 1407 Å, and 2783 - 2834 Å, including bright spectral lines
formed in the chromosphere (Mg II h 2803 Å and Mg II k 2796 Å) and
transition region (C II 1334/1335 Å and Si IV 1394/1403 Å). Slit-jaw
images in four different passbands (C II 1330, Si IV 1400, Mg II k
2796, and Mg II wing 2830 Å) can be taken simultaneously with spectral
rasters that sample regions up to 130 arcsec × 175 arcsec at a variety
of spatial samplings (from 0.33 arcsec and up). IRIS is sensitive to
emission from plasma at temperatures between 5000 K and 10 MK and will
advance our understanding of the flow of mass and energy through an
interface region, formed by the chromosphere and transition region,
between the photosphere and corona. This highly structured and dynamic
region not only acts as the conduit of all mass and energy feeding
into the corona and solar wind, it also requires an order of magnitude
more energy to heat than the corona and solar wind combined. The
IRIS investigation includes a strong numerical modeling component
based on advanced radiative-MHD codes to facilitate interpretation of
observations of this complex region. Approximately eight Gbytes of data
(after compression) are acquired by IRIS each day and made available
for unrestricted use within a few days of the observation.

---------------------------------------------------------
Title: Science with a Wide-field UV Transient Explorer
Authors: Sagiv, I.; Gal-Yam, A.; Ofek, E. O.; Waxman, E.; Aharonson,
O.; Kulkarni, S. R.; Nakar, E.; Maoz, D.; Trakhtenbrot, B.; Phinney,
E. S.; Topaz, J.; Beichman, C.; Murthy, J.; Worden, S. P.
2014AJ....147...79S Altcode: 2013arXiv1303.6194S
The time-variable electromagnetic sky has been well-explored at
a wide range of wavelengths. In contrast, the ultra-violet (UV)
variable sky is relatively poorly explored, even though it offers
exciting scientific prospects. Here, we review the potential scientific
impact of a wide-field UV survey on the study of explosive and other
transient events, as well as known classes of variable objects,
such as active galactic nuclei and variable stars. We quantify our
predictions using a fiducial set of observational parameters which
are similar to those envisaged for the proposed ULTRASAT mission. We
show that such a mission would be able to revolutionize our knowledge
about massive star explosions by measuring the early UV emission from
hundreds of events, revealing key physical parameters of the exploding
progenitor stars. Such a mission would also detect the UV emission from
many tens of tidal-disruption events of stars by supermassive black
holes at galactic nuclei and enable a measurement of the rate of such
events. The overlap of such a wide-field UV mission with existing and
planned gravitational-wave and high-energy neutrino telescopes makes
it especially timely.

---------------------------------------------------------
Title: Phobos and Deimos and Mars Environment (PADME): A LADEE-Derived
Mission to Explore Mars's Moons and the Martian Orbital Environment
Authors: Lee, P.; Bicay, M.; Colaprete, A.; Elphic, R.; Genova,
A.; Hine, B.; Horanyi, M.; Jaroux, B.; Korsmeyer, D.; Lewis, B. S.;
Worden, S. P.
2014LPI....45.2288L Altcode:
PADME is a proposed rapid low-cost NASA Mars orbiter mission that
will address longstanding unknowns about Mars’ two moons and the
circum-martian environment.

---------------------------------------------------------
Title: Mino's Smile
Authors: Worden, Pete
2014SPPhy.150....5W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Applicability of Emerging Quantum Computing Capabilities
to Exo-Planet Research
Authors: Correll, Randall; Worden, S.
2014AAS...22320601C Altcode:
In conjunction with the Universities Space Research Association and
Google, Inc. NASA Ames has acquired a quantum computing device built
by DWAVE Systems with approximately 512 “qubits.” Quantum computers
have the feature that their capabilities to find solutions to problems
with large numbers of variables scale linearly with the number of
variables rather than exponentially with that number. These devices
may have significant applicability to detection of exoplanet signals
in noisy data. We have therefore explored the application of quantum
computing to analyse stellar transiting exoplanet data from NASA’s
Kepler Mission. The analysis of the case studies was done using the
DWAVE Systems’s BlackBox compiler software emulator, although one
dataset was run successfully on the DWAVE Systems’s 512 qubit Vesuvius
machine. The approach first extracts a list of candidate transits from
the photometric lightcurve of a given Kepler target, and then applies a
quantum annealing algorithm to find periodicity matches between subsets
of the candidate transit list. We examined twelve case studies and were
successful in reproducing the results of the Kepler science pipeline
in finding validated exoplanets, and matched the results for a pair
of candidate exoplanets. We conclude that the current implementation
of the algorithm is not sufficiently challenging to require a quantum
computer as opposed to a conventional computer. We are developing
more robust algorithms better tailored to the quantum computer and
do believe that our approach has the potential to extract exoplanet
transits in some cases where a conventional approach would not in
Kepler data. Additionally, we believe the new quantum capabilities
may have even greater relevance for new exoplanet data sets such as
that contemplated for NASA’s Transiting Exoplanet Survey Satellite
(TESS) and other astrophysics data sets.

---------------------------------------------------------
Title: Solar Cycle Variability and Surface Differential Rotation
from Ca II K-line Time Series Data
Authors: Scargle, Jeffrey D.; Keil, Stephen L.; Worden, Simon P.
2013ApJ...771...33S Altcode: 2013arXiv1303.6303S
Analysis of over 36 yr of time series data from the NSO/AFRL/Sac Peak
K-line monitoring program elucidates 5 components of the variation of
the 7 measured chromospheric parameters: (a) the solar cycle (period
~ 11 yr), (b) quasi-periodic variations (periods ~ 100 days), (c) a
broadband stochastic process (wide range of periods), (d) rotational
modulation, and (e) random observational errors, independent of
(a)-(d). Correlation and power spectrum analyses elucidate periodic
and aperiodic variation of these parameters. Time-frequency analysis
illuminates periodic and quasi-periodic signals, details of frequency
modulation due to differential rotation, and in particular elucidates
the rather complex harmonic structure (a) and (b) at timescales in
the range ~0.1-10 yr. These results using only full-disk data suggest
that similar analyses will be useful for detecting and characterizing
differential rotation in stars from stellar light curves such as
those being produced by NASA's Kepler observatory. Component (c)
consists of variations over a range of timescales, in the manner
of a 1/f random process with a power-law slope index that varies
in a systematic way. A time-dependent Wilson-Bappu effect appears
to be present in the solar cycle variations (a), but not in the
more rapid variations of the stochastic process (c). Component (d)
characterizes differential rotation of the active regions. Component
(e) is of course not characteristic of solar variability, but the fact
that the observational errors are quite small greatly facilitates
the analysis of the other components. The data analyzed in this
paper can be found at the National Solar Observatory Web site <A
href="http://nsosp.nso.edu/cak_mon/">http://nsosp.nso.edu/cak_mon/</A>,
or by file transfer protocol at <A
href="ftp://ftp.nso.edu/idl/cak.parameters">ftp://ftp.nso.edu/idl/cak.parameters</A>.

---------------------------------------------------------
Title: The Interface Region Imaging Spectrograph (IRIS)
Authors: De Pontieu, Bart; Title, A. M.; Lemen, J.; Wuelser, J.;
Tarbell, T. D.; Schrijver, C. J.; Golub, L.; Kankelborg, C.; Carlsson,
M.; Hansteen, V. H.; Worden, S.; IRIS Team
2013SPD....44...03D Altcode:
The solar chromosphere and transition region (TR) form a highly
structured and dynamic interface region between the photosphere and
the corona. This region not only acts as the conduit of all mass and
energy feeding into the corona and solar wind, it also requires an
order of magnitude more energy to heat than the corona. Nevertheless,
the chromosphere remains poorly understood, because of the complexity
of the required observational and analytical tools: the interface
region is highly complex with transitions from optically thick to
optically thin radiation, from pressure to magnetic field domination,
and large density and temperature contrasts on small spatial scales. The
Interface Region Imaging Spectrograph (IRIS) was selected for a NASA
SMEX mission in 2009 and is scheduled to launch on 26-June-2013 (with
first light scheduled for mid July). IRIS addresses critical questions:
(1) Which types of non-thermal energy dominate in the chromosphere and
beyond? (2) How does the chromosphere regulate mass and energy supply
to the corona and heliosphere? (3) How do magnetic flux and matter
rise through the lower atmosphere, and what role does flux emergence
play in flares and mass ejections? These questions are addressed with
a high-resolution near and far UV imaging spectrometer sensitive to
emission from plasma at temperatures between 5,000 K and 10 MK. IRIS
has a field-of-view of 120 arcsec, a spatial resolution of 0.4 arcsec,
and velocity resolution of 0.5 km/s. The IRIS investigation includes
a strong numerical modeling component based on advanced radiative MHD
codes to facilitate interpretation of observations. We describe the
IRIS instrumentation and numerical modeling, and present the plans for
observations, calibration and data distribution. We will highlight some
of the issues that IRIS observations can help resolve. More information
can be found at http://iris.lmsal.com

---------------------------------------------------------
Title: LAGRANGE: LAser GRavitational-wave ANtenna in GEodetic Orbit
Authors: Buchman, S.; Conklin, J. W.; Balakrishnan, K.; Aguero,
V.; Alfauwaz, A.; Aljadaan, A.; Almajed, M.; Altwaijry, H.; Saud,
T. A.; Byer, R. L.; Bower, K.; Costello, B.; Cutler, G. D.; DeBra,
D. B.; Faied, D. M.; Foster, C.; Genova, A. L.; Hanson, J.; Hooper,
K.; Hultgren, E.; Klavins, A.; Lantz, B.; Lipa, J. A.; Palmer, A.;
Plante, B.; Sanchez, H. S.; Saraf, S.; Schaechter, D.; Shu, K.; Smith,
E.; Tenerelli, D.; Vanbezooijen, R.; Vasudevan, G.; Williams, S. D.;
Worden, S. P.; Zhou, J.; Zoellner, A.
2013ASPC..467..191B Altcode:
We describe a new space gravitational wave observatory design called
LAG-RANGE that maintains all important LISA science at about half the
cost and with reduced technical risk. It consists of three drag-free
spacecraft in a geocentric formation. Fixed antennas allow continuous
contact with the Earth, solving the problem of communications bandwidth
and latency. A 70 mm diameter sphere with a 35 mm gap to its enclosure
serves as the single inertial reference per spacecraft, operating in
“true” drag-free mode (no test mass forcing). Other advantages are:
a simple caging design based on the DISCOS 1972 drag-free mission,
an all optical read-out with pm fine and nm coarse sensors, and the
extensive technology heritage from the Honeywell gyroscopes, and the
DISCOS and Gravity Probe B drag-free sensors. An Interferometric
Measurement System, designed with reflective optics and a highly
stabilized frequency standard, performs the ranging between test
masses and requires a single optical bench with one laser per
spacecraft. Two 20 cm diameter telescopes per spacecraft, each with
infield pointing, incorporate novel technology developed for advanced
optical systems by Lockheed Martin, who also designed the spacecraft
based on a multi-flight proven bus structure. Additional technological
advancements include updated drag-free propulsion, thermal control,
charge management systems, and materials. LAGRANGE subsystems are
designed to be scalable and modular, making them interchangeable with
those of LISA or other gravitational science missions. We plan to space
qualify critical technologies on small and nano satellite flights,
with the first launch (UV-LED Sat) in 2013.

---------------------------------------------------------
Title: LIMSAT: An Ultra-violet Time Domain Explorer
Authors: Phinney, E. S.; Kulkarni, S. R.; Gal-Yam, A.; Ofek, E.;
Waxman, E.; Scargle, J.; Worden, S.; Murthy, J.
2013AAS...22135011P Altcode:
LIMSAT is a proposed joint US-Israel mini satellite aimed at systematic
time domain studies of the UV Universe. The satellite consists of
eight 12cm telescopes with a total instantaneous field of view of about
1100 square degrees in the spectral band 200-240nm. A sun-synchronous
orbit allows continuous viewing of the anti-sun equatorial region. In
one year LIMSAT would have covered an equatorial band (about 2.5% of
the sky), providing about one month of continuous photometry of all
objects in this field, with all data downlinked within 10 minutes of
acquisition. While the primary objective of LIMSAT is the detection
of shock breakout, secondary objectives include searches for tidal
disruption of stars passing perilously close to nuclear black holes,
systematic study of variability of AGN, cataclysmic variables,
activity studies of young stars and late type stars, unique studies
of extra-solar planets and eclipsing binaries. LIMSAT working along
with ground-based synoptic surveys will usher in a new era of time
domain studies.

---------------------------------------------------------
Title: Feasibility analysis for a manned mars free-return mission
in 2018
Authors: Tito, Dennis A.; Anderson, Grant; Carrico, John P.; Clark,
Jonathan; Finger, Barry; Lantz, Gary A.; Loucks, Michel E.; MacCallum,
Taber; Poynter, Jane; Squire, Thomas H.; Worden, S. Pete
2013aero.confE.352T Altcode:
In 1998 Patel et al searched for Earth-Mars free-return trajectories
that leave Earth, fly by Mars, and return to Earth without any
deterministic maneuvers after Trans-Mars Injection. They found fast
trajectory opportunities occurring two times every 15 years with
a 1.4-year duration, significantly less than most Mars free return
trajectories, which take up to 3.5 years. This paper investigates these
fast trajectories. It also determines the launch and life support
feasibility of flying such a mission using hardware expected to be
available in time for an optimized fast trajectory opportunity in
January, 2018.

---------------------------------------------------------
Title: Radar-Enabled Recovery of the Sutter’s Mill Meteorite,
a Carbonaceous Chondrite Regolith Breccia
Authors: Jenniskens, Peter; Fries, Marc D.; Yin, Qing-Zhu; Zolensky,
Michael; Krot, Alexander N.; Sandford, Scott A.; Sears, Derek;
Beauford, Robert; Ebel, Denton S.; Friedrich, Jon M.; Nagashima,
Kazuhide; Wimpenny, Josh; Yamakawa, Akane; Nishiizumi, Kunihiko;
Hamajima, Yasunori; Caffee, Marc W.; Welten, Kees C.; Laubenstein,
Matthias; Davis, Andrew M.; Simon, Steven B.; Heck, Philipp R.;
Young, Edward D.; Kohl, Issaku E.; Thiemens, Mark H.; Nunn, Morgan H.;
Mikouchi, Takashi; Hagiya, Kenji; Ohsumi, Kazumasa; Cahill, Thomas A.;
Lawton, Jonathan A.; Barnes, David; Steele, Andrew; Rochette, Pierre;
Verosub, Kenneth L.; Gattacceca, Jérôme; Cooper, George; Glavin,
Daniel P.; Burton, Aaron S.; Dworkin, Jason P.; Elsila, Jamie E.;
Pizzarello, Sandra; Ogliore, Ryan; Schmitt-Kopplin, Phillipe; Harir,
Mourad; Hertkorn, Norbert; Verchovsky, Alexander; Grady, Monica; Nagao,
Keisuke; Okazaki, Ryuji; Takechi, Hiroyuki; Hiroi, Takahiro; Smith,
Ken; Silber, Elizabeth A.; Brown, Peter G.; Albers, Jim; Klotz, Doug;
Hankey, Mike; Matson, Robert; Fries, Jeffrey A.; Walker, Richard J.;
Puchtel, Igor; Lee, Cin-Ty A.; Erdman, Monica E.; Eppich, Gary R.;
Roeske, Sarah; Gabelica, Zelimir; Lerche, Michael; Nuevo, Michel;
Girten, Beverly; Worden, Simon P.
2012Sci...338.1583J Altcode:
Doppler weather radar imaging enabled the rapid recovery of the
Sutter’s Mill meteorite after a rare 4-kiloton of TNT-equivalent
asteroid impact over the foothills of the Sierra Nevada in northern
California. The recovered meteorites survived a record high-speed
entry of 28.6 kilometers per second from an orbit close to that of
Jupiter-family comets (Tisserand’s parameter = 2.8 ± 0.3). Sutter’s
Mill is a regolith breccia composed of CM (Mighei)-type carbonaceous
chondrite and highly reduced xenolithic materials. It exhibits
considerable diversity of mineralogy, petrography, and isotope and
organic chemistry, resulting from a complex formation history of the
parent body surface. That diversity is quickly masked by alteration
once in the terrestrial environment but will need to be considered
when samples returned by missions to C-class asteroids are interpreted.

---------------------------------------------------------
Title: Recovery of the Sutter's Mill Meteorite
Authors: Jenniskens, P.; Girten, B.; Sears, D.; Sandford, S.; Cooper,
G.; Ehrgott, A.; Koop, M.; Albers, J.; Fries, M.; Klotz, D.; Hankey,
M.; Schmidt, G.; Worden, P.
2012M&PSA..75.5376J Altcode:
On April 22, 2012, a small asteroid scattered carbonaceous
chondrites near Sutter's Mill. Peter Jenniskens recovered one fragment
pre-rain. NASA Ames Research Center's Lunar Science Institute followed
up with organized searches.

---------------------------------------------------------
Title: A Space-Based, Near-Sun Survey to Discover Atira and Aten
Orbital Class Near-Earth Objects
Authors: Hildebrand, A. R.; Gladman, B.; Tedesco, E. F.; Cardinal,
R. D.; Gural, P. S.; Granvik, M.; Larson, S. M.; Chodas, P. W.;
Greenstreet, S.; Carroll, K. A.; Brown, P. G.; Wiegert, P.; Worden,
S. P.; Wallace, B. J.
2012LPICo1667.6463H Altcode:
The NEOSSat spacecraft will efficiently discover Atira and Aten orbital
class near-Earth asteroids by searching arcs of sky across the ecliptic
plane to within 45 degrees of the Sun. Approximately 10 Atiras are
expected to be discovered per year.

---------------------------------------------------------
Title: LAGRANGE: LAser GRavitational-wave ANtenna at GEo-lunar
Lagrange points
Authors: Conklin, J. W.; Buchman, S.; Aguero, V.; Alfauwaz, A.;
Aljadaan, A.; Almajed, M.; Altwaijry, H.; Al-Saud, T.; Balakrishnan,
K.; Byer, R. L.; Bower, K.; Costello, B.; Cutler, G. D.; DeBra,
D. B.; Faied, D. M.; Foster, C.; Genova, A. L.; Hanson, J.; Hooper,
K.; Hultgren, E.; Jaroux, B.; Klavins, A.; Lantz, B.; Lipa, J. A.;
Palmer, A.; Plante, B.; Sanchez, H. S.; Saraf, S.; Schaechter, D.;
Sherrill, T.; Shu, K. -L.; Smith, E.; Tenerelli, D.; Vanbezooijen, R.;
Vasudevan, G.; Williams, S. D.; Worden, S. P.; Zhou, J.; Zoellner, A.
2011arXiv1111.5264C Altcode:
We describe a new space gravitational wave observatory design called
LAGRANGE that maintains all important LISA science at about half the
cost and with reduced technical risk. It consists of three drag-free
spacecraft in the most stable geocentric formation, the Earth-Moon L3,
L4, and L5 Lagrange points. Fixed antennas allow continuous contact
with the Earth, solving the problem of communications bandwidth
and latency. A 70 mm diameter AuPt sphere with a 35 mm gap to its
enclosure serves as a single inertial reference per spacecraft, which
is operated in "true" drag-free mode (no test mass forcing). This is
the core of the Modular Gravitational Reference Sensor whose other
advantages are: a simple caging design based on the DISCOS 1972
drag-free mission, an all optical read-out with pm fine and nm coarse
sensors, and the extensive technology heritage from the Honeywell
gyroscopes, and the DISCOS and Gravity Probe B drag-free sensors. An
Interferometric Measurement System, designed with reflective optics
and a highly stabilized frequency standard, performs the inter-test
mass ranging and requires a single optical bench with one laser per
spacecraft. Two 20 cm diameter telescopes per spacecraft, each with
in-field pointing, incorporate novel technology developed for advanced
optical systems by Lockheed Martin, who also designed the spacecraft
based on a multi-flight proven bus structure. Additional technological
advancements include the drag-free propulsion, thermal control, charge
management systems, and materials. LAGRANGE sub-systems are designed
to be scalable and modular, making them interchangeable with those
of LISA or other gravitational science missions. We plan to space
qualify critical technologies on small and nano satellite flights,
with the first launch (UV-LED Sat) in 2013.

---------------------------------------------------------
Title: Solar Cycle Fine Structure and Surface Rotation from Ca II
K-Line Time Series Data
Authors: Scargle, Jeff; Keil, Steve; Worden, Pete
2011sdmi.confE..77S Altcode:
Analysis of three and a half decades of data from the NSO/AFRL/Sac Peak
K-line monitoring program yields evidence for four components to the
variation: (a) the solar cycle, with considerable fine structure and
a quasi-periodicity of 122.4 days; (b) a stochastic process, faster
than (a) and largely independent of it, (c) a quasi-periodic signal
due to rotational modulation, and of course (d) observational errors
(shown to be quite small). Correlation and power spectrum analyses
elucidate periodic and aperiodic variation of these chromospheric
parameters. Time-frequency analysis is especially useful for
extracting information about differential rotation, and in particular
elucidates the connection between its behavior and fine structure of
the solar cycle on approximately one-year time scales. These results
further suggest that similar analyses will be useful at detecting and
characterizing differential rotation in stars from stellar light-curves
such as those being produced by NASA's Kepler observatory. Component (b)
consists of variations over a range of timescales, in the manner of a
"1/f" random process. A time-dependent Wilson-Bappu effect appears to
be present in the solar cycle variations (a), but not in the stochastic
process (b). The data can be found at the National Solar Observatory
web site http://nsosp.nso.edu/data/cak_mon.html, or by file transfer
protocol at ftp://ftp.nso.edu/idl/cak.parameters.

---------------------------------------------------------
Title: Gravity Probe B: Final Results of a Space Experiment to Test
General Relativity
Authors: Everitt, C. W. F.; Debra, D. B.; Parkinson, B. W.; Turneaure,
J. P.; Conklin, J. W.; Heifetz, M. I.; Keiser, G. M.; Silbergleit,
A. S.; Holmes, T.; Kolodziejczak, J.; Al-Meshari, M.; Mester, J. C.;
Muhlfelder, B.; Solomonik, V. G.; Stahl, K.; Worden, P. W., Jr.;
Bencze, W.; Buchman, S.; Clarke, B.; Al-Jadaan, A.; Al-Jibreen, H.; Li,
J.; Lipa, J. A.; Lockhart, J. M.; Al-Suwaidan, B.; Taber, M.; Wang, S.
2011PhRvL.106v1101E Altcode: 2011arXiv1105.3456E
Gravity Probe B, launched 20 April 2004, is a space experiment
testing two fundamental predictions of Einstein’s theory of general
relativity (GR), the geodetic and frame-dragging effects, by means of
cryogenic gyroscopes in Earth orbit. Data collection started 28 August
2004 and ended 14 August 2005. Analysis of the data from all four
gyroscopes results in a geodetic drift rate of -6601.8±18.3mas/yr
and a frame-dragging drift rate of -37.2±7.2mas/yr, to be compared
with the GR predictions of -6606.1mas/yr and -39.2mas/yr, respectively
(“mas” is milliarcsecond; 1mas=4.848×10-9rad).

---------------------------------------------------------
Title: Transiting Exoplanet Survey Satellite (TESS)
Authors: Ricker, George R.; Latham, D. W.; Vanderspek, R. K.; Ennico,
K. A.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau,
D.; Clampin, M.; Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot,
J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai,
N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.;
Schingler, R. H.; Seager, S.; Torres, G.; Udry, S.; Villasenor, J. N.;
Winn, J. N.; Worden, S. P.
2010AAS...21545006R Altcode: 2010BAAS...42..459R
TESS is a low-cost SMEX-class satellite mission. In a two-year all-sky
survey, TESS will observe more than 2,000,000 nearby stars, searching
for temporary drops in brightness caused by planetary transits. TESS is expected to identify more than 1000 transiting exoplanet
candidates, including a sample of about 100 Super Earths---small
rock-and-ice planets in the range 1 to 10 Earth masses---orbiting F,
G, K, and M dwarfs. TESS's "wide-shallow” survey complements the
"narrow-deep” CoRoT and Kepler surveys. TESS-discovered transiting
systems will be nearby (&lt; 50 pc), and typically 10-20 x brighter than
those discovered by CoRoT and Kepler. Thus, the resulting TESS Transit
Catalog will comprise all of the best transiting systems for follow-up
observations. TESS will identify Super Earths orbiting IR-bright stars,
within reach of JWST spectroscopic searches for planetary water and
carbon dioxide. TESS is a collaborative effort led by researchers
at the Massachusetts Institute of Technology, the Harvard-Smithsonian
Center for Astrophysics, and the NASA Ames Research Center. Additional
TESS scientific partners include Las Cumbres Observatory Global
Telescope, Lowell Observatory, the NASA Goddard Space Flight Center,
the Infrared Processing and Analysis Center at the California Institute
of Technology, the Geneva Observatory (Switzerland), the Tokyo Institute
of Technology (Japan), and Institut Supérieur de l'Aéronautique et
de l'Espace (France). TESS was funded by NASA for a Phase A study
from May 2008 - June 2009, but was not selected for flight. Additional
funding leading to a flight opportunity is being sought. Support has
also been provided by the Kavli Foundation, Google, and the Smithsonian
Institution. TESS could launch as early as 2013-2014.

---------------------------------------------------------
Title: Estimates of the Population of Exoplanets Discoverable by
the Transiting Exoplanet Survey Satellite (TESS)
Authors: Seager, Sara; Winn, J. N.; Ricker, G. R.; Latham, D. W.;
Vanderspek, R. K.; Ennico, K. A.; Bakos, G.; Brown, T. M.; Burgasser,
A. J.; Charbonneau, D.; Clampin, M.; Deming, L. D.; Doty, J. P.;
Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins,
J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.;
Martel, F.; Sasselov, D. D.; Schingler, R. H.; Torres, G.; Udry, S.;
Villasenor, J. N.; Worden, S. P.
2010AAS...21545004S Altcode: 2010BAAS...42R.458S
In a two year survey, the Transiting Exoplanet Survey Satellite
(TESS) will search the entire sky for planets orbiting nearby,
bright stars. In this paper, we calculate the number of transiting
planets that TESS will detect, as a function of the properties of the
planet and the properties of the host star. The ingredients in this
calculation are divided into five groups: The properties of the
planet: its radius r and orbital distance a. The properties of
the star: its luminosity L, mass M, radius R, and number density n in
our Galactic neighborhood. The TESS instrumental parameters: its
effective area, bandpass, and limiting photometric precision. The
TESS survey parameters: the characteristics of the input catalog (2.5
million V &lt; 13.5 dwarfs over the whole sky), observing duty cycle
(observing a given star 10.3% of the time), and duration of observations
for a given star (72 days). The abundance of planets around stars,
which may depend on r, a, and L The calculation is performed for
a three-dimensional grid of planet/star/orbit combinations, in which
the three parameters are the planet radius r, the stellar luminosity L,
and the orbital distance a. For the range of instrument and population
parameters and assumptions considered, we estimate that TESS will detect
1600-2700 planets in total, of which 100-300 should be small planets:
SuperEarths or Earths. Support for this work has been provided
by NASA, the Kavli Foundation, Google, and the Smithsonian Institution.

---------------------------------------------------------
Title: Gravity Probe B Data Analysis
Authors: Everitt, C. W. F.; Adams, M.; Bencze, W.; Buchman, S.;
Clarke, B.; Conklin, J. W.; DeBra, D. B.; Dolphin, M.; Heifetz, M.;
Hipkins, D.; Holmes, T.; Keiser, G. M.; Kolodziejczak, J.; Li, J.;
Lipa, J.; Lockhart, J. M.; Mester, J. C.; Muhlfelder, B.; Ohshima,
Y.; Parkinson, B. W.; Salomon, M.; Silbergleit, A.; Solomonik, V.;
Stahl, K.; Taber, M.; Turneaure, J. P.; Wang, S.; Worden, P. W., Jr.
2010png..book...53E Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Monte Carlo Simulations of Transit Light Curves for the
Transiting Exoplanet Survey Satellite (TESS)
Authors: Jernigan, J. G.; Villasenor, J. N.; Ricker, G. R.; Latham,
D. W.; Vanderspek, R. K.; Ennico, K. A.; Bakos, G.; Brown, T. M.;
Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L. D.;
Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.;
Jenkins, J. M.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel,
F.; Sasselov, D. D.; Schingler, R. H.; Seager, S.; Torres, G.; Udry,
S.; Winn, J. N.; Worden, S. P.
2010AAS...21545003J Altcode: 2010BAAS...42..458J
During the Phase A for TESS, simulations of planetary transits were
performed to confirm the instrument's ability to detect transits. The
simulations cover the full TESS discovery space in the planet
period-transit duration plane. Examples included a 36-day period planet,
two previously known systems (HAT-P-11 and CoRoT 7B), and one Earth
and one SuperEarth. In addition, a broad matrix of planetary periods
and transit depths were also simulated. We present simulated light
curves of transiting planets that are typical of those that TESS will
detect. Each light curve is computed via a Monte Carlo algorithm. The
timing of the optical emission includes the parameters of orbital
motion for the planet-star system. All simulations include estimates
of the noise from the following effects: spacecraft pointing jitter,
vignetting, optical PSF wings, background effects, CCD gain and bias
instability, sky background, and intrinsic stellar variability. The
stellar variability includes a scaled, full temporal power spectrum
of the Sun. Typical light curves of planet-star systems are simulated
for a 72 day duration with a 10 minute time resolution of each TESS
sample. These simulated light curves are analyzed to determine estimates
of the S/N for detection for each simulated system. Support for this
work has been provided by NASA, the Kavli Foundation, Google, and the
Smithsonian Institution.

---------------------------------------------------------
Title: High-Precision Imaging Photometers for the Transient Exoplanet
Survey Satellite
Authors: Kraft Vanderspek, Roland; Ricker, G. R.; Latham, D. W.;
Ennico, K.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau,
D.; Clampin, M.; Deming, L.; Doty, J. P.; Dunham, E. W.; Elliot,
J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.;
Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov,
D. D.; Schingler, R. H.; Seager, S.; Szentgyorgyi, A.; Torres, G.;
Udry, S.; Villasenor, J. N.; Winn, J. N.; Worden, S. P.
2010AAS...21545007K Altcode: 2010BAAS...42..459K
The Transient Exoplanet Survey Satellite (TESS) is designed to
search for transiting exoplanet systems around all stars with V &lt;
12. The TESS payload consists of a bank of six identical, wide-field,
high-precision imaging photometers. When deployed on the highly-stable
TESS satellite platform, these photometers can perform &lt;200 ppm
photometry for V=8 stars (∼100 ppm for V=6 stars) in a 10-minute
observation. We describe the components of the TESS imaging photometers:
the custom, wide-field optics; the large-area CCD arrays; and the
low-power, high precision CCD electronics. Support for TESS has been
provided by NASA, the Kavli Foundation, Google, and the Smithsonian
Institution.

---------------------------------------------------------
Title: Data Network for the TESS Mission
Authors: Martel, Francois; Villasenor, J. N.; Ricker, G. R.; Latham,
D. W.; Vanderspek, R. K.; Ennico, K. A.; Bakos, G.; Brown, T. M.;
Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L. D.; Doty,
J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins,
J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.;
Sasselov, D. D.; Schingler, R. H.; Seager, S.; Torres, G.; Udry, S.;
Winn, J. N.; Worden, S. P.
2010AAS...21545002M Altcode: 2010BAAS...42..458M
The Transiting Exoplanet Survey Satellite (TESS) is designed for an
all-sky photometric survey of bright stars, extending&amp;nbspover the
entire celestial sphere.&amp;nbspTESS will catalog planetary transits
of nearby stars that can be followed-up with ground observatories. The
satellite cameras will perform measurements of 2,500,000 stars with
brightness ranging from V=4.5 to V=13.5 within two years, and download
typically 4.7 G Bytes of data per day.&amp;nbspWe describe the TESS
operation plan and the communication and ground system designed to
download and process the TESS data. The dedicated ground system uses
a network of S-band ground stations spaced around the equator which
allows three communications passes per orbit, at data rates of 3.5
Mbit/sec, for up to 45 data downloads per day. Satellite operations
and data download are controlled remotely through the internet by
the TESS Mission Operation Center at NASA Ames Research Center, which
transfers the TESS observation data for processing and distribution to
the Science Operation Center managed by &amp;nbspMIT and Harvard-SAO
in Cambridge. Support for this work has been provided by NASA, the
Kavli Foundation, Google, and the Smithsonian Institution.

---------------------------------------------------------
Title: Transiting Exoplanet Survey Satellite (TESS) Community Observer
Program including the Science Enhancement Option Box (SEO Box) -
12 TB On-board Flash Memory for Serendipitous Science
Authors: Schingler, Robert; Villasenor, J. N.; Ricker, G. R.; Latham,
D. W.; Vanderspek, R. K.; Ennico, K. A.; Lewis, B. S.; Bakos, G.;
Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming,
L. D.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida,
S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.;
Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Seager, S.; Torres,
G.; Udry, S.; Winn, J. N.; Worden, S. P.
2010AAS...21545001S Altcode: 2010BAAS...42Q.458S
The Transiting Exoplanet Survey Satellite (TESS) will perform an
all-sky survey in a low-inclination, low-Earth orbit. TESS's 144
GB of raw data collected each orbit will be stacked, cleaned, cut,
compressed and downloaded. The Community Observer Program is a Science
Enhancement Option (SEO) that takes advantage of the low-radiation
environment, technology advances in flash memory, and the vast amount
of astronomical data collected by TESS. The Community Observer Program
requires the addition of a 12 TB "SEO Box” inside the TESS Bus. The
hardware can be built using low-cost Commercial Off-The-Shelf (COTS)
components and fits within TESS's margins while accommodating GSFC
gold rules. The SEO Box collects and stores a duplicate of the
TESS camera data at a "raw” stage ( 4.3 GB/orbit, after stacking and
cleaning) and makes them available for on-board processing. The sheer
amount of onboard storage provided by the SEO Box allows the stacking
and storing of several months of data, allowing the investigator
to probe deeper in time prior to a given event. Additionally, with
computation power and data in standard formats, investigators can
utilize data-mining techniques to investigate serendipitous phenomenon,
including pulsating stars, eclipsing binaries, supernovae or other
transient phenomena. The Community Observer Program enables ad-hoc
teams of citizen scientists to propose, test, refine and rank algorithms
for on-board analysis to support serendipitous science. Combining
"best practices” of online collaboration, with careful moderation
and community management, enables this `crowd sourced’ participatory
exploration with a minimal risk and impact on the core TESS Team. This
system provides a powerful and independent tool opening a wide range of
opportunity for science enhancement and secondary science. Support
for this work has been provided by NASA, the Kavli Foundation, Google,
and the Smithsonian Institution.

---------------------------------------------------------
Title: Improved Accuracy of the Gravity Probe B Science Results
Authors: Conklin, John; Adams, M.; Aljadaan, A.; Aljibreen, H.;
Almeshari, M.; Alsuwaidan, B.; Bencze, W.; Buchman, S.; Clarke,
B.; Debra, D. B.; Everitt, C. W. F.; Heifetz, M.; Holmes, T.;
Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lipa, J.; Lockhart,
J. M.; Muhlfelder, B.; Parkinson, B. W.; Salomon, M.; Silbergleit,
A.; Solomonik, V.; Stahl, K.; Taber, M.; Turneaure, J. P.; Worden,
P. W., Jr.
2010cosp...38.3734C Altcode: 2010cosp.meet.3734C
This paper presents the progress in the science data analysis for
the Gravity Probe B (GP-B) experiment. GP-B, sponsored by NASA
and launched in April of 2004, tests two fundamental predictions
of general relativity, the geodetic effect and the frame-dragging
effect. The GP-B spacecraft measures the non-Newtonian drift rates
of four ultra-precise cryogenic gyroscopes placed in a circular polar
Low Earth Orbit. Science data was collected from 28 August 2004 until
cryogen depletion on 29 September 2005. The data analysis is complicated
by two unexpected phenomena, a) a continually damping gyroscope polhode
affecting the calibration of the gyro readout scale factor, and b)
two larger than expected classes of Newtonian torque acting on the
gyroscopes. Experimental evidence strongly suggests that both effects
are caused by non-uniform electric potentials (i.e. the patch effect)
on the surfaces of the gyroscope rotor and its housing. At the end
of 2008, the data analysis team reported intermediate results showing
that the two complications are well understood and are separable from
the relativity signal. Since then we have developed the final GP-B data
analysis code, the "2-second Filter", which provides the most accurate
and precise determination of the non-Newtonian drifts attainable in the
presence of the two Newtonian torques and the fundamental instrument
noise. This limit is roughly 5

---------------------------------------------------------
Title: Gravity Probe B Data Analysis. Status and Potential for
Improved Accuracy of Scientific Results
Authors: Everitt, C. W. F.; Adams, M.; Bencze, W.; Buchman, S.;
Clarke, B.; Conklin, J. W.; Debra, D. B.; Dolphin, M.; Heifetz, M.;
Hipkins, D.; Holmes, T.; Keiser, G. M.; Kolodziejczak, J.; Li, J.;
Lipa, J.; Lockhart, J. M.; Mester, J. C.; Muhlfelder, B.; Ohshima,
Y.; Parkinson, B. W.; Salomon, M.; Silbergleit, A.; Solomonik, V.;
Stahl, K.; Taber, M.; Turneaure, J. P.; Wang, S.; Worden, P. W.
2009SSRv..148...53E Altcode:
This is the first of five connected papers detailing progress on the
Gravity Probe B (GP-B) Relativity Mission. GP-B, launched 20 April
2004, is a landmark physics experiment in space to test two fundamental
predictions of Einstein’s general relativity theory, the geodetic
and frame-dragging effects, by means of cryogenic gyroscopes in Earth
orbit. Data collection began 28 August 2004 and science operations
were completed 29 September 2005. The data analysis has proven deeper
than expected as a result of two mutually reinforcing complications
in gyroscope performance: (1) a changing polhode path affecting the
calibration of the gyroscope scale factor C g against the
aberration of starlight and (2) two larger than expected manifestations
of a Newtonian gyro torque due to patch potentials on the rotor and
housing. In earlier papers, we reported two methods, ‘geometric’
and ‘algebraic’, for identifying and removing the first Newtonian
effect (‘misalignment torque’), and also a preliminary method of
treating the second (‘roll-polhode resonance torque’). Central to
the progress in both torque modeling and C g determination
has been an extended effort on “Trapped Flux Mapping” commenced
in November 2006. A turning point came in August 2008 when it became
possible to include a detailed history of the resonance torques into
the computation. The East-West (frame-dragging) effect is now plainly
visible in the processed data. The current statistical uncertainty
from an analysis of 155 days of data is 5.4 marc-s/yr (∼14% of
the predicted effect), though it must be emphasized that this is a
preliminary result requiring rigorous investigation of systematics
by methods discussed in the accompanying paper by Muhlfelder et al. A
covariance analysis incorporating models of the patch effect torques
indicates that a 3-5% determination of frame-dragging is possible with
more complete, computationally intensive data analysis.

---------------------------------------------------------
Title: Polhode Motion, Trapped Flux, and the GP-B Science Data
Analysis
Authors: Silbergleit, A.; Conklin, J.; Debra, D.; Dolphin, M.; Keiser,
G.; Kozaczuk, J.; Santiago, D.; Salomon, M.; Worden, P.
2009SSRv..148..397S Altcode:
Magnetic field trapped in the Gravity Probe B (GP-B) gyroscope rotors
contributes to the scale factor of the science readout signal. This
contribution is modulated by the rotor’s polhode motion. In orbit,
polhode period was observed to change due to a small energy dissipation,
which significantly complicates data analysis. We present precise
values of spin phase, spin down rate, polhode phase and angle, and scale
factor variations obtained from the data by Trapped Flux Mapping. This
method finds the (unique) trapped field distribution and rotor motion by
fitting a theoretical model to the harmonics of high (gyroscope spin)
frequency signal. The results are crucial for accurately determining
the gyroscope relativistic drift rate from the science signal.

---------------------------------------------------------
Title: GP-B Systematic Error Determination
Authors: Muhlfelder, B.; Adams, M.; Clarke, B.; Keiser, G. M.;
Kolodziejczak, J.; Li, J.; Lockhart, J. M.; Worden, P.
2009SSRv..148..429M Altcode:
We have evaluated the systematic error in the GP-B experiment using
five different approaches and estimated the individual contributions
of many error sources. The systematic effects we consider include
those due to gyroscope torques, gyroscope readout, telescope readout,
and guide star proper motion. Effects with an estimated impact on the
experiment error larger than 1 mas/yr are discussed in detail. Examples
of analyses that bound other sources to less than 1 mas/yr are included
to show the range of techniques employed to perform this work. We
describe the remaining tasks to complete the systematic error analysis
and estimate the total experiment uncertainty.

---------------------------------------------------------
Title: Transiting Exoplanet Survey Satellite (TESS)
Authors: Ricker, George R.; Latham, D. W.; Vanderspek, R. K.; Ennico,
K. A.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau,
D.; Clampin, M.; Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot,
J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai,
N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.;
Schingler, R. H.; Seager, S.; Torres, G.; Udry, S.; Villasenor, J. S.;
Winn, J. N.; Worden, S. P.
2009AAS...21430605R Altcode:
The Transiting Exoplanet Survey Satellite (TESS) is a low
cost, SMEX-class planet finder. In a two year all-sky survey,
TESS will observe more than two million bright, nearby stars,
searching for temporary drops in brightness that are caused by
planetary transits. Such transits not only provide the means of
identifying the planet, but also provide knowledge of the planet's
diameter, mass density, surface gravity, temperature, and other key
properties. TESS is expected to detect more than 1000 transiting
exoplanet candidates. These detections will include a sample of
100 Super Earths -- small rock-and-ice planets with masses in the
range 1 to 10 Earth masses -- orbiting nearby stars with spectral
types spanning a broad range, including F, G, K, and M dwarfs. No
ground-based survey can achieve this feat. TESS's "wide-shallow" survey
complements the "narrow-deep" Corot and Kepler mission surveys. The
resulting TESS Transit Catalog of the nearest and brightest stars
in the sky will constitute a unique scientific legacy for followup
observations. TESS will identify Super Earths orbiting IR-bright stars,
ideal for JWST searches for planetary water and carbon dioxide. The TESS mission is a collaborative effort led by researchers at
the Massachusetts Institute of Technology, the Harvard-Smithsonian
Center for Astrophysics, and the NASA Ames Research Center. Additional
TESS partners include ATK Space Systems, the Las Cumbres Observatory
Global Telescope Network, Lowell Observatory, the NASA Goddard Space
Flight Center, the Infrared Processing and Analysis Center at the
California Institute of Technology, the University of California
(Berkeley and Santa Cruz), the SETI Institute, Espace Incorporated,
the Geneva Observatory (Switzerland), the Tokyo Institute of Technology
(Japan), and Institut Supérieur de l'Aéronautique et de l'Espace
(France). TESS is currently completing a NASA-funded Phase A study,
and is proposed for launch in December 2012.

---------------------------------------------------------
Title: ASIMA -- Asteroid Impact Analyzer: A Proposed Close-to-Home
Planetary Mission to Probe the Diversity of Comets and Asteroids
Authors: Jenniskens, P.; Dissly, R.; Boyd, I. D.; Revelle, D. O.;
Nuth, J. A.; Worden, S. P.
2009LPI....40.2305J Altcode:
The proposed Asteroid Impact Analyzer (ASIMA) is a Partner Mission
of Opportunity that will measure how the bulk carbon-to-metal ratio
varies among comets and asteroids.

---------------------------------------------------------
Title: The impact and recovery of asteroid 2008 TC3
Authors: Jenniskens, P.; Shaddad, M. H.; Numan, D.; Elsir, S.; Kudoda,
A. M.; Zolensky, M. E.; Le, L.; Robinson, G. A.; Friedrich, J. M.;
Rumble, D.; Steele, A.; Chesley, S. R.; Fitzsimmons, A.; Duddy, S.;
Hsieh, H. H.; Ramsay, G.; Brown, P. G.; Edwards, W. N.; Tagliaferri,
E.; Boslough, M. B.; Spalding, R. E.; Dantowitz, R.; Kozubal, M.;
Pravec, P.; Borovicka, J.; Charvat, Z.; Vaubaillon, J.; Kuiper, J.;
Albers, J.; Bishop, J. L.; Mancinelli, R. L.; Sandford, S. A.; Milam,
S. N.; Nuevo, M.; Worden, S. P.
2009Natur.458..485J Altcode:
In the absence of a firm link between individual meteorites and their
asteroidal parent bodies, asteroids are typically characterized only
by their light reflection properties, and grouped accordingly into
classes. On 6 October 2008, a small asteroid was discovered with
a flat reflectance spectrum in the 554-995nm wavelength range, and
designated 2008 TC3 (refs 4-6). It subsequently hit the
Earth. Because it exploded at 37km altitude, no macroscopic fragments
were expected to survive. Here we report that a dedicated search along
the approach trajectory recovered 47 meteorites, fragments of a single
body named Almahata Sitta, with a total mass of 3.95kg. Analysis of one
of these meteorites shows it to be an achondrite, a polymict ureilite,
anomalous in its class: ultra-fine-grained and porous, with large
carbonaceous grains. The combined asteroid and meteorite reflectance
spectra identify the asteroid as F class, now firmly linked to dark
carbon-rich anomalous ureilites, a material so fragile it was not
previously represented in meteorite collections.

---------------------------------------------------------
Title: The Transiting Exoplanet Survey Satellite (TESS)
Authors: Ricker, George R.; Latham, D. W.; Vanderspek, R. K.; Ennico,
K. A.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.;
Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman,
M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin,
G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Schingler,
R. H.; Seager, S.; Torres, G.; Udry, S.; Villasenor, J. S.; Winn,
J. N.; Worden, S. P.
2009AAS...21340301R Altcode: 2009BAAS...41..193R
The Transiting Exoplanet Survey Satellite (TESS) is a low cost,
SMEX-class planet finder. In a two year all-sky survey, TESS will
observe more than two million bright, nearby stars, searching for
temporary drops in brightness that are caused by planetary transits,
which occur when a planet's orbit carries it directly in front of its
parent star. Such transits not only provide the means of identifying
the planet, but also provide knowledge of the planet's diameter, mass
density, surface gravity, temperature, and other key properties. TESS is expected to catalog more than 1000 transiting exoplanet
candidates--20 times as many as are presently known, including a
sample of 'super Earths'. The TESS "wide-shallow" survey will be
complementary to the "narrow-deep" ones of the Corot and Kepler
missions: its sky coverage will exceed that of Corot by 1000 times,
and that of Kepler by 400 times. Because the TESS all-sky survey will
systematically examine every interesting bright star likely to harbor an
exoplanet, the resulting TESS Transit Catalog will constitute a unique
scientific legacy. High resolution, follow-up ground-based optical and
space-based IR spectroscopy of exoplanets demands bright targets. Thus,
TESS should identify those new exoplanets that are ideal for study
with the world's largest ground-based telescopes, as well as with
NASA's upcoming James Webb Space Telescope. The TESS mission is a
collaborative effort led by researchers at MIT, the Harvard-Smithsonian
Center for Astrophysics, and the NASA Ames Research Center. Additional
TESS partners include the NASA Goddard Space Flight Center, the Harvard
Origins of Life Initiative, Lowell Observatory, Caltech's IPAC, the
SETI Institute, Geneva Observatory in Switzerland, Tokyo Institute
of Technology, SUPAERO in France, ATK Space, Espace Inc, and the Las
Cumbres Observatory Global Telescope Network. TESS has been accepted
for Phase A study by NASA, and is proposed for launch in late 2012.

---------------------------------------------------------
Title: Astronomy Enabled by Ares V -- A Workshop
Authors: Lester, Daniel F.; Langhoff, S.; Worden, S. P.; Thronson,
H.; Correll, R.
2009AAS...21345008L Altcode: 2009BAAS...41R.343L
On April 26th and 27th, 2008, NASA Ames Research Center hosted a two-day
weekend workshop entitled "Astronomy Enabled by Ares V.” The primary
goal of the workshop was to begin the process of bringing the Ares
V designers together with senior representatives of the astronomical
community to discuss the feasibility of using the Ares V heavy-lift
launch vehicle to enable both new astronomical telescope architectures
and new science. When developed in the latter part of the upcoming
decade Ares V will be by far the most capable launch vehicle, with
mass and volume launch capability many times that now available. The
vehicle is understood to be the main workhorse in carrying humans and
cargo to the Moon and beyond and, as such, is a key lynchpin for NASA's
new space transportation architecture. Participants included experts
from academia, industry, and NASA, including representatives of the
Constellation architecture. Participants considered, in the context of
identified astronomy needs: (1) Are there telescope concepts or missions
capable of breakthrough science that are either enabled or significantly
enhanced by the capabilities of an Ares V? (2) What demands do large
telescopes place on the payload environment of the Ares V, such as
mass, volume, fairing shape, cleanliness, acoustics, etc.? (3) What
technology and environmental issues need to be addressed to facilitate
launching observatories on an Ares V? (4) Is there a trade-off between
mass and complexity that could reduce launch risk and, thereby, the
cost of building large telescopes? We report on the results of this
workshop, which included discussion on the operations model for such
large-investment astronomical facilities. Such an operations model
might well involve human and or robotic maintenance and servicing, in
order to fully capitalize on the science potential of such facilities.

---------------------------------------------------------
Title: The Large Benefits of Small Satellite Missions
Authors: Baker, Daniel N.; Worden, S. Pete; Buchman, S.; Byer, Robert;
DeBra, Dan; Mester, John
2009astro2010P..67B Altcode: 2009astro2010P..67W
No abstract at ADS

---------------------------------------------------------
Title: Step Prototype Development Status
Authors: Mehls, C.; Bayart, C.; Bower, J.; Clarke, B.; Cox, C.; Gill,
D.; Stricker, D.; Vora, N.; Wang, S.; Zhou, P.; Torii, R.; Worden,
P.; Debra, D.; Dittus, H.; Loeffler, F.
2008mgm..conf.2553M Altcode:
STEP, the Satellite Test of the Equivalence Principle [1], proposes
to test the Equivalence Principle to a part in 1018 by
comparing the free-fall acceleration of cylindrical shaped test masses
[2] in Earth orbit. Magnetic bearings constrain the test mass motion
to their axis of symmetry [3]. The displacement of the test masses is
measured using a DC SQUID and superconducting coils [4], enabling a
displacement sensitivity as small as 10-15 m. In combination
with a small spring stiffness a differential acceleration sensitivity
of 10-18 g is achievable. Residual satellite acceleration
is reduced to better than 10-14 g by compensating satellite
drag forces with thrust provided by helium gas. We report on recent
progress in the development of STEP prototype flight accelerometers,
in particular the development of the high precision quartz housing
for the engineering inner accelerometer and the testing of SQUID and
capacitive readout systems using 'brass board' accelerometer prototypes.

---------------------------------------------------------
Title: Constraining the Atira Orbital Class (IEO`s) Asteroid
Population with the Near Earth Object Surveillance Satellite
(NEOSSat) Mission
Authors: Hildebrand, Alan; Tedesco, E.; Cardinal, R.; Gladman, B.;
Matthews, J.; Wallace, B.; Larson, S.; Gural, P.; Chodas, P.; Granvik,
M.; Wiegert, P.; Brown, P.; Worden, S.; Carroll, K.
2008DPS....40.5207H Altcode: 2008BAAS...40..493H
The Atira orbital class of NEO's (by definition) always occurs
inside Earth's orbit, and can only be found at relatively low
solar elongations by ground-based searches. The latter surveys have
succeeded in discovering 9 Atiras to date, but the discovery rate can
be substantially augmented using a space-based telescope designed to
image near the Sun. The NEOSSat microsatellite is designed to search the
ecliptic plane at 45 to 55° solar elongation and ±40; degrees ecliptic
latitude; near-Sun surveying is considerably compromised by zodiacal
light brightness in visible wavelengths, but even lower elongations
could be profitably searched. The spacecraft is a derivative of the
Microvariablity and Oscillations of Stars (MOST) microsatellite
weighing 65 kg with a 15 cm aperture f5.88 Maksutov telescope,
and will be deployed in a Sun synchronous orbit. The spacecraft is
a dual use mission and will also be used to image high Earth orbit
artificial satellites. Under favourable circumstances the asteroid
search project will cover 1200 square degrees of sky per month with
limiting V magnitudes of 20. Planned survey cadence will be 4 images
over 125 minutes; this cadence is tied to the NEOSSat orbital period
of 100 minutes. A space-based telescope benefits from relatively
low backgrounds, "continuous” and predictable availability, and
the ability to use parallax to discriminate NEO's from the Main
Belt population by determining distances to all NEO discoveries;
a space-based sensor has the disadvantage of comparatively long slew
times between fields. NEOSSat will be able to discover approximately
one third of the Atira population &gt;1; km in diameter in a 3 year
survey (the spacecraft will detect Atiras to 18.5 H magnitude); 50%
of the &gt;1; km diameter Aten class population will be detected during
the same interval.

---------------------------------------------------------
Title: The Large Benefits of Small-Satellite Missions
Authors: Baker, Daniel N.; Worden, S. Pete
2008EOSTr..89..301B Altcode:
Small-spacecraft missions play a key and compelling role in
space-based scientific and engineering programs [Moretto and Robinson,
2008]. Compared with larger satellites, which can be in excess of 2000
kilograms, small satellites range from 750 kilograms-roughly the size of
a golf cart-to less than 1 kilogram, about the size of a softball. They
have been responsible for greatly reducing the time needed to obtain
science and technology results. The shorter development times for
smaller missions can reduce overall costs and can thus provide welcome
budgetary options for highly constrained space programs. In many cases,
we contend that 80% (or more) of program goals can be achieved for 20%
of the cost by using small-spacecraft solutions.

---------------------------------------------------------
Title: A Cryogenic Liquid-Mirror Telescope on the Moon to Study the
Early Universe
Authors: Angel, Roger; Worden, Simon P.; Borra, Ermanno F.; Eisenstein,
Daniel J.; Foing, Bernard; Hickson, Paul; Josset, Jean-Luc; Bui Ma, Ki;
Seddiki, Omar; Sivanandam, Suresh; Thibault, Simon; van Susante, Paul
2008ApJ...680.1582A Altcode: 2008arXiv0806.2241A
We have studied the feasibility and scientific potential of zenith
observing liquid-mirror telescopes having 20-100 m diameters located
on the Moon. They would carry out deep infrared surveys to study the
distant universe and follow up discoveries made with the 6 m James Webb
Space Telescope (JWST), with more detailed images and spectroscopic
studies. They could detect objects 100 times fainter than JWST,
observing the first high-redshift stars in the early universe and their
assembly into galaxies. We explored the scientific opportunities,
key technologies, and optimum location of such telescopes. We have
demonstrated critical technologies. For example, the primary mirror
would necessitate a high-reflectivity liquid that does not evaporate
in the lunar vacuum and remains liquid at less than 100 K. We have
made a crucial demonstration by successfully coating an ionic liquid
that has negligible vapor pressure. We also successfully experimented
with a liquid mirror spinning on a superconducting bearing, as will
be needed for the cryogenic, vacuum environment of the telescope. We
have investigated issues related to lunar locations, concluding
that locations within a few kilometers of a pole are ideal for deep
sky cover and long integration times. We have located ridges and
crater rims within 0.5° of the north pole that are illuminated for
at least some sun angles during lunar winter, providing power and
temperature control. We also have identified potential problems, like
lunar dust. Issues raised by our preliminary study demand additional
in-depth analyses. These issues must be fully examined as part of a
scientific debate that we hope to start with the present article.

---------------------------------------------------------
Title: Gravity Probe B data analysis status and potential for improved
accuracy of scientific results
Authors: Everitt, C. W. F.; Adams, M.; Bencze, W.; Buchman, S.; Clarke,
B.; Conklin, J.; DeBra, D. B.; Dolphin, M.; Heifetz, M.; Hipkins,
D.; Holmes, T.; Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lockhart,
J. M.; Muhlfelder, B.; Parkinson, B. W.; Salomon, M.; Silbergleit,
A.; Solomonik, V.; Stahl, K.; Turneaure, J. P.; Worden, P. W., Jr.
2008CQGra..25k4002E Altcode:
Gravity Probe B (GP-B) is a landmark physics experiment in space
designed to yield precise tests of two fundamental predictions of
Einstein's theory of general relativity, the geodetic and frame-dragging
effects, by means of cryogenic gyroscopes in Earth orbit. Launched on
20 April 2004, data collection began on 28 August 2004 and science
operations were completed on 29 September 2005 upon liquid helium
depletion. During the course of the experiment, two unexpected and
mutually-reinforcing complications were discovered: (1) larger than
expected 'misalignment' torques on the gyroscopes producing classical
drifts larger than the relativity effects under study and (2) a
damped polhode oscillation that complicated the calibration of the
instrument's scale factor against the aberration of starlight. Steady
progress through 2006 and 2007 established the methods for treating
both problems; in particular, an extended effort from January 2007 on
'trapped flux mapping' led in August 2007 to a dramatic breakthrough,
resulting in a factor of ~20 reduction in data scatter. This paper
reports results up to November 2007. Detailed investigation of a
central 85-day segment of the data has yielded robust measurements of
both relativity effects. Expansion to the complete science data set,
along with anticipated improvements in modeling and in the treatment
of systematic errors may be expected to yield a 3 6% determination of
the frame-dragging effect.

---------------------------------------------------------
Title: The Near Earth Object Surveillance Satellite (NEOSSat)
Mission Will Conduct an Efficient Space-Based Asteroid Survey at
Low Solar Elongations
Authors: Hildebrand, A. R.; Tedesco, E. F.; Carroll, K. A.; Cardinal,
R. D.; Matthews, J. M.; Gladman, B.; Kaiser, N. R.; Brown, P. G.;
Wiegert, P.; Larson, S. M.; Worden, S. P.; Wallace, B. J.; Chodas,
P. W.; Granvik, M.; Gural, P.
2008LPICo1405.8293H Altcode:
No abstract at ADS

---------------------------------------------------------
Title: UARC/NASA Near Earth Object Small Spacecraft Summer Program
Authors: Asphaug, E.; Delory, G. T.; Korycansky, D.; Marchis, F.;
de Pater, I.; Hines, J.; Worden, P.; 2008 S4P Summer Students
2008LPICo1405.8386A Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Small Spacecraft in Support of the Lunar Exploration Program
Authors: Worden, S. P.; Weston, A. R.
2007LPICo1371.3019W Altcode: 2007eelo.work.3019W
No abstract at ADS

---------------------------------------------------------
Title: Deposition of metal films on an ionic liquid as a basis for
a lunar telescope
Authors: Borra, Ermanno F.; Seddiki, Omar; Angel, Roger; Eisenstein,
Daniel; Hickson, Paul; Seddon, Kenneth R.; Worden, Simon P.
2007Natur.447..979B Altcode:
An optical/infrared telescope of 20-100m aperture located on the Moon
would be able to observe objects 100 to 1,000 times fainter than the
proposed next generation of space telescopes. The infrared region of
the spectrum is particularly important for observations of objects
at redshifts z&gt;7. The apparent simplicity and low mass of a liquid
mirror telescope, compared with a traditional pointable glass mirror,
suggest that the concept should be considered further. A previously
proposed liquid mirror telescope, based upon a spinning liquid metallic
alloy, is not appropriate for infrared applications, which will require
a liquid below 130K. Here we report the successful coating of an ionic
liquid with silver. The surface is smooth and the silver coating is
stable on a timescale of months. The underlying ionic liquid does
not evaporate in a vacuum and remains liquid down to a temperature of
175K. Given that there are ~106 simple and ~1018
ternary ionic liquids, it should be possible to synthesize liquids
with even lower melting temperatures.

---------------------------------------------------------
Title: The Near Earth Object Surveillance Satellite (NEOSSat)
Mission Enables an Efficient Space-Based Survey (NESS Project)
of Interior-to-Earth-Orbit (IEO) Asteroids
Authors: Hildebrand, A. R.; Tedesco, E. F.; Carroll, K. A.; Cardinal,
R. D.; Matthews, J. M.; Kuschnig, R.; Walker, G. A. H.; Gladman, B.;
Kaiser, N. R.; Brown, P. G.; Larson, S. M.; Worden, S. P.; Wallace,
B. J.; Chodas, P. W.; Muinonen, K.; Cheng, A.; Gural, P.
2007LPI....38.2372H Altcode:
The NEOSSat microsatellite will be used to discover and track NEOs
with an emphasis on interior-to-Earth-orbit objects.

---------------------------------------------------------
Title: STEP (satellite test of the equivalence principle)
Authors: Sumner, T. J.; Anderson, J.; Blaser, J. -P.; Cruise, A. M.;
Damour, T.; Dittus, H.; Everitt, C. W. F.; Foulon, B.; Jafry, Y.;
Kent, B. J.; Lockerbie, N.; Loeffler, F.; Mann, G.; Mester, J.; Pegrum,
C.; Reinhardt, R.; Sandford, M.; Scheicher, A.; Speake, C. C.; Torii,
R.; Theil, S.; Touboul, P.; Vitale, S.; Vodel, W.; Worden, P. W.
2007AdSpR..39..254S Altcode:
STEP is one of a number of missions now being developed to take
advantage of the quiet space environment to carry out very sensitive
gravitational experiments. Using pairs of concentric free-falling
proof-masses, STEP will be able to test the equivalence principle
(EP) to a sensitivity at least five orders of magnitude better than
currently achievable on ground. The EP is a founding principle of
general relativity and STEP is the most sensitive experiment of this
type planned so far, aiming at 1 part in 10 18.

---------------------------------------------------------
Title: Low-Cost Small Spacecraft for Multiple Asteroid Studies
Authors: Worden, S. P.; Correll, R. C.
2006LPICo1325...78W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A Lunar Liquid Mirror Telescope (LLMT) for deep-field infrared
observations near the lunar pole
Authors: Angel, Roger; Eisenstein, Dan; Sivanandam, Suresh; Worden,
Simon P.; Burge, Jim; Borra, Ermanno; Gosselin, Clément; Seddiki,
Omar; Hickson, Paul; Ma, Ki Bui; Foing, Bernard; Josset, Jean-Luc;
Thibault, Simon; Van Susante, Paul
2006SPIE.6265E..1UA Altcode: 2006SPIE.6265E..54A
We have studied the feasibility and scientific potential of a 20 - 100
m aperture astronomical telescope at the lunar pole, with its primary
mirror made of spinning liquid at less than 100K. Such a telescope,
equipped with imaging and multiplexed spectroscopic instruments for
a deep infrared survey, would be revolutionary in its power to study
the distant universe, including the formation of the first stars and
their assembly into galaxies. The LLMT could be used to follow up
discoveries made with the 6 m James Webb Space Telescope, with more
detailed images and spectroscopic studies, as well as to detect objects
100 times fainter, such as the first, high-red shift stars in the early
universe. Our preliminary analysis based on SMART-1 AMIE images shows
ridges and crater rims within 0.5° of the North Pole are illuminated
for at least some sun angles during lunar winter. Locations near these
points may prove to be ideal for the LLMT. Lunar dust deposited on
the optics or in a thin atmosphere could be problematic. An in-situ
site survey appears necessary to resolve the dust questions.

---------------------------------------------------------
Title: Access to Space: A Strategy for the Twenty-First Century
Authors: Worden, Simon; Sponable, Jess
2006AstPo...4...69W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: STEP Accelerometer Response under Non-Equilibrium Conditions
Authors: Wang, S.; Ambekar, P.; Bayart, C.; Torii, R.; Worden, P.;
Debra, D.
2006cosp...36.3462W Altcode: 2006cosp.meet.3462W
The STEP Satellite Test of the Equivalence Principle accelerometer
performance is derived under the assumption that the test mass is
properly constrained and positioned 5DOF in the housing cavity test mass
is in the operational sweet-spot It is extremely useful to check system
response when the mass is outside the sweet-spot Using a 1m long fiber
suspended test mass we have made past studies on magnetic suspension
forces Fy and Fz and have explored the housing cavity in 3DOF x y and z
translation limited by uncertainty in test mass tilt angle qy and qz To
address this limitation we have recently constructed a 2-axis cryogenic
tilt platform The laboratory version of position readout electronics
allow us to measure the test mass position at 4K to a precision of
1 nm and tilt angle to less than 1 arc sec in 100 seconds We will
present recent experimental data showing the dynamic response of the
capacitance measurement subsystem as a function of test mass position

---------------------------------------------------------
Title: STEP Baseline Design and Validation
Authors: Torii, R.; Kolodziejczak, J.; Worden, P.; Step Team
2006cosp...36.3595T Altcode: 2006cosp.meet.3595T
STEP Satellite Test of the Equivalence Principle proposes to test the
Equivalence Principle to a part in 10 18 by comparing the free-fall
acceleration of test masses in orbit about the Earth The baseline
design goal is to resolve a difference in acceleration of 4x10 -19 g
in approximately 10 5 s Demonstrating this level of sensitivity by
a test on the ground is not possible limited by seismic and other
disturbances An analysis of the acceleration measurement subsystem
shows more than adequate sensitivity and an extensive system analysis
in which external disturbances and the effect of other subsystems are
included in a self-consistent model has also shown that the baseline
design goal can be achieved Our approach to validate the baseline
design is to focus on verifying the assumptions used in analysis We
will discuss how this approach has been implemented in our recent
manufacture and test of prototype accelerometers and in our future
plans for prototype instrument testing

---------------------------------------------------------
Title: The Demise of US Spacepower: Not with a Bang but a Whimper
Authors: Correll, Randall; Worden, Simon
2005AstPo...3..233C Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Testable lightweight telescopes for space
Authors: Angel, Roger; Burge, Jim; Worden, S. P.
2005SPIE.5899..325A Altcode:
The next generation of larger space optics will need lightweight and
deployed mirror systems in order to control costs and fit within
current and planned launch vehicle fairings. These will require
active control based on wavefront sensing to establish and maintain
their optical quality. Such control has been the enabling factor
for the current generation of 8 m class ground-based telescopes,
whose mirrors are either single monoliths with detailed shape
control or have multiple rigid segments with control of relative
position. They use actuator densities of typically a few per square
meter. For active space systems it will be highly desirable to test
the full deployed spacecraft in a vacuum test with a scene simulator,
to validate before launch the optical performance of the complete
system with its closed loop control systems. To enable such testing,
the space mirror system must be designed from the start to work in a
1g as well as zero g environment. The orientation we envisage has the
spacecraft system pointed at the zenith, illuminated by a downward beam
collimated with reference to a full aperture liquid flat. We consider
here two space mirror systems. The first has rigid segments supported
by position actuators to control only rigid body motions. Since the
segments under test must hold their shape with an axial 1g load and
no passive flotation supports, they must be smaller than for ground
systems. If made of lightweighted silicon carbide or beryllium for
diffraction limited imaging in the optical, they would have to be ~
30 cm in diameter. A mirror systems made from such segments will
require about 40 actuators and wavefront sensor sub-apertures per
square meter. The second system is a lightweight 3.5x8 m monolith for
very high contrast imaging, as is envisaged for NASA's Terrestrial
Planet Finder. High accuracy control of Fourier components down to ~
0.2 m period is required, requiring a deformable mirror with about 4000
actuators. If the primary itself is the deformable element, and has a 1
cm thick glass meniscus facesheet weighing 600 kg, the gravity-induced
quilting during testing would be about 1 nm rms, low enough for ground
testing of the complete system at the desired 10-10 contrast level.

---------------------------------------------------------
Title: A Deep-Field Infrared Observatory Near the Lunar Pole
Authors: Borra, E. F.; Seddiki, O.; Angel, J. R. P.; Worden, S. P.;
Eisenstein, D.; Silvanandam, S.; Hickson, P.; Ma, K.
2005JRASC..99R.134B Altcode:
A study has been made of the feasibility and scientific potential
of a 20-to 100-m aperture astronomical telescope at the lunar pole,
with its primary mirror made of spinning liquid at &lt; 100 K. Such
a telescope, equipped with imaging and multiplexed spectroscopic
instruments for a deep-infrared survey, would be revolutionary in its
power to study the distant Universe, including the formation of the
first stars and their assembly into galaxies. Our study explored the
scientific opportunities, key technologies, and optimum location of
such a Lunar Liquid Mirror Telescope (LLMT). An optical design for a 20-
m telescope with diffraction limited imaging over a 15-arcminute field
has been developed. It would be used to follow up on discoveries made
with the 6-m James Webb Space Telescope, with more detailed images and
spectroscopic studies, as well as to detect objects 100 times fainter,
such as the first high-redshift star in the early Universe. Amodel was
made of a liquid mirror spinning on a superconducting bearing, as will
be needed for the cryogenic, vacuum environment of the LLMT. Reflective
silver coatings have been deposited for the first time on a liquid
surface, needed to make infrared mirrors at ~80 K. Issues relating to
polar locations have been explored. Dust on the optics or in a thin
atmosphere, though unlikely to be problematic at the poles, should be
investigated in-situ. Issues relating to polar locations have been
explored. Locations at or within a few km of a pole are preferred
for deep-sky cover, and allow for long integration times by simple
instrument rotation. This revolutionary mission concept could provide
a scientific focus to NASA's planned exploration of the Moon, just as
currently HST stands as a major achievement of its Shuttle Program.

---------------------------------------------------------
Title: Leadership for new US strategic directions
Authors: Worden, Simon P.; Correll, Randall R.
2005SpPol..21...21W Altcode:
Although faced with the new global challenges of terrorism and peer
competition, the USA has been slow to adapt its cold war forces,
and newer 'warfighter' strategy to meet them. Cyberspace and outer
space offer the means to do this, via 'responsive' microsatellites and
low-cost launchers, and broadband internet information and education
services. The US military leadership is, however, not well enough versed
in these technologies, with senior personnel largely lacking a space
or technical background and having little appetite for change. If the
USA is successfully to meet current challenges, it must first create a
leadership that is technologically capable and philosophically attuned
to change.

---------------------------------------------------------
Title: Advantages of Searching for Asteroids from Low Earth Orbit:
the NEOSSat Mission
Authors: Hildebrand, A. R.; Carroll, K. A.; Tedesco, E. F.; Faber,
D. R.; Cardinal, R. D.; Matthews, J. M.; Kuschnig, R.; Walker,
G. A. H.; Gladman, B.; Pazder, J.; Brown, P. G.; Larson, S. M.;
Worden, S. P.; Wallace, B. J.; Chodas, P. W.; Muinonen, K.; Cheng, A.
2004EM&P...95...33H Altcode: 2005EM&P...95...33H
Space-based observatories have several advantages over ground-based
observatories in searching for asteroids and comets. In particular,
the Aten and Interior to Earth’s Orbit (IEO) asteroid classes may be
efficiently sought at low solar elongations along the ecliptic plane. A
telescope in low Earth orbit has a sufficiently long orbital baseline to
determine the parallax for all Aten and IEO class asteroids discovered
with this observing strategy. The Near Earth Object Space Surveillance
Satellite (NEOSSat) mission will launch a microsatellite to exploit
this observing strategy complementing ground-based search programmes.

---------------------------------------------------------
Title: Step (satellite Test of the Equivalence Principle)
Authors: Sumner, T. J.; Everitt, C. W. F.; Mester, J.; Torii, R.;
Worden, P.; Lockerbie, N.; Pegrum, C.; Anderson, J.; Mann, G.; Blaser,
J. -P.; Cruise, A. M.; Speake, C. C.; Damour, T.; Vitale, S.; Dittus,
H.; Foulon, B.; Touboul, P.; Kent, B. J.; Sandford, M.; Jafry, Y.;
Reinhardt, R.; Loeffler, F.; Vodel, W.
2004apsp.conf..148S Altcode:
STEP is one of a number of missions now being developed to take
advantage of the quiet space environment to carry out very sensitive
gravitational experiments. Using pairs of concentric free-falling
proof-masses, STEP will be able to test the Equivalence Principle
(EP) to a sensitivity at least five orders of magnitude better than
currently achievable on ground. The EP is a founding principle of
general relativity and STEP is the most sensitive experiment of this
type planned so far, aiming at 1 part in 1018.

---------------------------------------------------------
Title: Testing STEP Accelerometers Using Fiber Suspended Test Mass
Authors: Wang, S.; Cordouan, J.; Torii, R.; Worden, P.
2004cosp...35.3175W Altcode: 2004cosp.meet.3175W
STEP (Satellite Test of the Equivalence Principle) proposes to
test the Equivalence Principle to one part in 1018 by
comparing the rate of fall of test mass pairs in Earth orbit. Test
mass acceleration is determined by displacement measurement under
known spring stiffness. The STEP accelerometer has one primary axis of
measurement (sensitive axis) defined very precisely by superconducting
magnetic bearings. First qualitative measurements of forces produced
by prototype flight bearings were performed in 2002. The bearing was
tested by trapping a fixed persistent current, and then measuring the
resulting static radial forces on a test mass (forces orthogonal to
the accelerometer sensitive axis). The test mass was suspended by a
meter long fiber with the cryogenic apparatus platform under 1-axis
tilt control. We will present recent test data and our plans for
a future major upgrade to improve performance and increase dynamic
testing capabilities.

---------------------------------------------------------
Title: The NASA-ESA MiniSTEP payload
Authors: Worden, P. W.; Torii, R.; Everitt, C. W. F.
2003AdSpR..32.1379W Altcode:
The Equivalence Principle, which states that gravitational mass and
inertial mass are different ways of measuring the same property, is
the experimental foundation for modern gravitational theory. Modern
theory cannot reconcile gravity with the other fundamental forces. One
possibility is that the present theory of gravity, general relativity,
is incomplete or incorrect. If this is the case, the Equivalence
Principle may be violated at some level beyond the one part in 10
12 that has been experimentally verified. The goal of the
Satellite Test of the Equivalence Principle (STEP) is to improve this
result to better than one part in 10 18. In STEP two or
more concentric, cylindrical test masses "fall" around the Earth in a
drag-free satellite. The masses are cooled to &lt; 2K and supported
by frictionless, superconducting, linear bearings. Ultra-sensitive
SQUID position detectors measure their relative motion. A confirmed
violation could provide key information toward the possible unification
of the four fundamental forces; conversely, a null result can rule
out competing theories or constrain new theories. MiniSTEP is the
least expensive mission proposed to date that still achieves STEP's
basic scientific goal. It compares four different materials in four
differential accelerometers. Cost saving is achieved by operating the
accelerometers sequentially, thereby avoiding duplicated equipment. The
drag-free satellite will be built around an existing superfluid helium
dewar and a small, semi-production spacecraft. A small commercial
launch vehicle will place the satellite in a 400 km, sun-synchronous,
polar, Earth orbit. Nominal mission lifetime is four months - but a
six to eight month life is expected.

---------------------------------------------------------
Title: The flux of small near-Earth objects colliding with the Earth
Authors: Brown, P.; Spalding, R. E.; ReVelle, D. O.; Tagliaferri,
E.; Worden, S. P.
2002Natur.420..294B Altcode:
Asteroids with diameters smaller than ~50-100m that collide with
the Earth usually do not hit the ground as a single body; rather,
they detonate in the atmosphere. These small objects can still cause
considerable damage, such as occurred near Tunguska, Siberia, in
1908. The flux of small bodies is poorly constrained, however, in part
because ground-based observational searches pursue strategies that lead
them preferentially to find larger objects. A Tunguska-class event-the
energy of which we take to be equivalent to 10 megatons of TNT-was
previously estimated to occur every 200-300 years, with the largest
annual airburst calculated to be ~20 kilotons (kton) TNT equivalent
(ref. 4). Here we report satellite records of bolide detonations
in the atmosphere over the past 8.5 years. We find that the flux of
objects in the 1-10-m size range has the same power-law distribution
as bodies with diameters &gt;50m. From this we estimate that the Earth
is hit on average annually by an object with ~5kton equivalent energy,
and that Tunguska-like events occur about once every 1,000 years.

---------------------------------------------------------
Title: Mitigation of near-earth object impacts
Authors: Worden, S.; Brown, P.
2002cosp...34E.440W Altcode: 2002cosp.meetE.440W
As our ability to survey and catalog potentially threatening
Near-Earth Objects (NEOs) grows we will inevitably find some that
are potentially threatening. Numerous authors have conjectured about
potential mitigation schemes. These schemes include destruction or
diversion via nuclear or chemical explosives if time is short. In
the case of much longer warning times low-thrust diversion schemes,
some taking advantage of natural effects such as radiation pressure
have been forwarded. Others advocate focusing our efforts on passive
schemes analogous to nuclear warfare civil defense. However, any
effective mitigation scheme should follow proven military operations
precepts. These include equal attention to decision making and command
and control organizations and technology. As we consider serious
approaches to NEO impact mitigation we must pay equal or greater
attention to how decisions will be made and mission control exercises
as we do to the more exciting "weapons."

---------------------------------------------------------
Title: The size of meteoroid constituent grains: Implications for
interstellar meteoroids
Authors: Hawkes, R. L.; Campbell, M. D.; Leblanc, A. G.; Parker, L.;
Brown, P.; Jones, J.; Worden, S. P.; Correll, R. R.; Woodworth, S. C.;
Fisher, A. A.; Gural, P.; Murray, I. S.; Connors, M.; Montague, T.;
Jewell, D.; Babcock, D. D.
2002dsso.conf...23H Altcode: 2002IAUCo.181...23H
No abstract at ADS

---------------------------------------------------------
Title: The STEP mission: principles and baseline design
Authors: Mester, J.; Torii, R.; Worden, P.; Lockerbie, N.; Vitale,
S.; Everitt, C. W. F.
2001CQGra..18.2475M Altcode:
The Satellite Test of the Equivalence Principle (STEP) will test the
equality of fall of objects in Earth orbit to an accuracy approaching
one part in 108 by measuring the difference in rate of
fall of test cylinders in cryogenic differential accelerometers in a
drag-free satellite. This paper describes the current baseline design
and principles used in the design of the STEP mission.

---------------------------------------------------------
Title: STEP error model development
Authors: Worden, P.; Mester, J.; Torii, R.
2001CQGra..18.2543W Altcode:
We describe the ongoing development of a comprehensive error model for
the satellite test of the equivalence principle, STEP. The goal is to
employ a model of the experiment and apparatus as a self-consistent
whole. The model uses a set of input parameters based on experiment
design and the measured characteristics of STEP sensor systems. The
output of the model evaluates specific disturbances to the test masses
in the general categories of thermal noise, gas pressure forces,
electrical forces, magnetic forces, gravitational forces, radiation
pressure and vibration. Use of the model to set experiment requirements
and to evaluate design trade-offs are briefly discussed.

---------------------------------------------------------
Title: The Near-Earth Space Surveillance (NESS) Mission: Discovery,
Tracking, and Characterization of Asteroids, Comets, and Artificial
Satellites with a Microsatellite
Authors: Hildebrand, A. R.; Carroll, K. A.; Balam, D. D.; Cardinal,
R. D.; Matthews, J. M.; Kuschnig, R.; Walker, G. A. H.; Brown, P. G.;
Tedesco, E. F.; Worden, S. P.; Burrell, D. A.; Chodas, P. W.; Larson,
S. M.; Spahr, T. B.; Wallace, B. J.
2001LPI....32.1790H Altcode:
The Near-Earth Space Surveillance (NESS) Mission, a microsatellite
dedicated to observing near-Earth (NEO) and interior-to-the-Earth
(IEO)asteroids and comets plus artificial satellites, is currently
being studied under contract to the Canadian Space Agency.

---------------------------------------------------------
Title: Image-intensified video results from the 1998 Leonid shower:
I. Atmospheric trajectories and physical structure
Authors: Campbell, M. D.; Brown, P. G.; Leblanc, A. G.; Hawkes, R. L.;
Jones, J.; Worden, S. P.; Correll, R. R.
2000M&PS...35.1259C Altcode:
Two station electro-optical observations of the 1998 Leonid shower
are presented. Precise heights and light curves were obtained for 79
Leonids which ranged in brightness (at maximum luminosity) from +0.3
to +6.1 astronomical magnitude. The mean photometric mass of the data
sample was 1.4x10-6 kg. The dependence of astronomical magnitude at
peak luminosity on photometric mass and zenith angle was consistent
with earlier studies of faint sporadic meteors. For example, a Leonid
meteoroid with a photometric mass of about 1.0x10-7 kg corresponds to
a peak meteor luminosity of about +4.5 astronomical magnitudes. The
mean beginning height of the Leonid meteors in this sample was 112.6
km and the mean ending height was 95.3 km. The highest beginning
height observed was 144.3 km. There is relatively little dependence
of either the first or last heights on mass, which is indicative
of meteoroids which have clustered into constituent grains prior
to the onset of intensive grain ablation. The height distribution,
combined with numerical modelling of the ablation of the meteoroids,
suggests that silicate-like materials are not the principle component
of Leonid meteoroids, and hints at the presence of a more volatile
component. Light curves of many Leonids were examined for evidence
of the physical structure of the associated meteoroids: like the 1997
Leonids, the narrow, nearly symmetric curves imply that the meteoroids
are not solid objects. The light curves are consistent with a dustball
structure.

---------------------------------------------------------
Title: Evidence for transverse spread in Leonid meteors
Authors: LeBlanc, A. G.; Murray, I. S.; Hawkes, R. L.; Worden, P.;
Campbell, M. D.; Brown, P.; Jenniskens, P.; Correll, R. R.; Montague,
T.; Babcock, D. D.
2000MNRAS.313L...9L Altcode:
We report here evidence for significant transverse spread of the
light production region in bright Leonid meteors. One Leonid meteor
has an apparent spread in the light production region of about 600m
perpendicular to the flight path for the meteor, that transverse spread
persisting for at least 0.3s. We have also detected short-duration,
jet-like features emanating from a bright Leonid meteor recorded in
1998. These jet-like features have maximum spatial dimensions up to
1.9km. While we cannot definitively rule out instrumental artefacts as
a cause for these jet-like features, they may be evidence of motion
contributing to the observed spatial spread in the light production
region.

---------------------------------------------------------
Title: The 1998 International Leonid Expedition.
Authors: Brown, P.; Campbell, M.; Jones, J.; Webster, A. R.; Hawkes,
R.; Leblanc, A.; Murray, I.; Ellis, K.; Correll, R.; Worden, S. P.;
Bedard, M.; Jewell, D.; Montague, T.; Thorne, J.; Tilton, B.; Gural,
P.; Babcock, D.; Worsfold, R.; Connors, M.; Hildebrand, A. R.; Molau,
S.; Rendtel, J.; Sponder, R.; Baayraa, T.; Batmunkh, D.; Bekhtur,
B.; Garradd, K. G.; McNaught, R. H.; Beech, M.
2000JRASC..94...24B Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Global Ground-Based Electro-Optical and Radar Observations
of the 1999 Leonid Shower: First Results
Authors: Brown, P.; Campbell, M. D.; Ellis, K. J.; Hawkes, R. L.;
Jones, J.; Gural, P.; Babcock, D.; Barnbaum, C.; Bartlett, R. K.;
Bedard, M.; Bedient, J.; Beech, M.; Brosch, N.; Clifton, S.;
Connors, M.; Cooke, B.; Goetz, P.; Gaines, J. K.; Gramer, L.; Gray,
J.; Hildebrand, A. R.; Jewell, D.; Jones, A.; Leake, M.; Leblanc,
A. G.; Looper, J. K.; Mcintosh, B. A.; Montague, T.; Morrow, M. J.;
Murray, I. S.; Nikolova, S.; Robichaud, J.; Spondor, R.; Talarico,
J.; Theijsmeijer, C.; Tilton, B.; Treu, M.; Vachon, C.; Webster,
A. R.; Weryk, R.; Worden, S. P.
2000lsr..book..167B Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Step Payload and Experiment
Authors: Worden, P.; Torii, R.; Mester, J. C.; Everitt, C. W. F.
2000fps..conf.1205W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The STEP Payload and Experiment
Authors: Worden, P.; Torii, R.; Mester, J. C.; Everitt, C. W. F.
2000AdSpR..25.1205W Altcode:
The foundation of modern gravitational theory is the Equivalence
Principle. General Relativity is incompatible with theories of other
fundamental forces such as QED, suggesting that it is incomplete. For
example, there may be additional forces coupled to baryon number or
spin. In this case the Equivalence Principle may be violated below
the experimentally verified level of one part in 1012. A
violation could provide crucial information for new theories. A
team of US and European scientists has assembled to do the Satellite
Test of the Equivalence Principle (STEP) with the goal of improving
this measurement to 1 part in 1018. In STEP two or more
test masses “fall” around the earth in a drag free satellite. A
difference in the rate of fall appears as a periodic difference in
their acceleration. The test masses are cooled to less than 2K and are
supported by frictionless superconducting bearings. Ultra-sensitive
SQUID position sensors measure their relative motion and their common
motion is removed by adjustments during acceleration maneuvers. Any
Equivalence Principle signal is separated from major disturbances by
rotation of the spacecraft. STEP is planned to be launched by 2004,
with nominal mission lifetime of 6 months

---------------------------------------------------------
Title: The Leonids 1998 results and implications for the future.
Authors: Hawkes, R.; Connors, M.; Hildebrand, A. R.; Ellis, K. J.;
Molau, S.; Rendtel, J.; Baayraa, T.; Batmunkh, D.; Bekhtur, B.;
Leblanc, A.; Murray, I.; Sponder, R.; Beech, M.; Gural, P.; Thorne,
J.; Bedard, M.; Correll, R.; Jewell, D.; Montague, T.; Tilton, B.;
Worden, S. P.; Brown, P.; Campbell, M.; Jones, J.; Webster, A. R.;
Babcock, D.; Worsfold, R.; Jenniskens, P.; Garradd, G.; McNaught, R. H.
1999JRASC..93Q.176H Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Global Ground-Based Electro-Optical and Radar Observations
of the 1999 Leonid Shower: First Results
Authors: Brown, P.; Campbell, M. D.; Ellis, K. J.; Hawkes, R. L.;
Jones, J.; Gural, P.; Babcock, D.; Barnbaum, C.; Bartlett, R. K.;
Bedard, M.; Bedient, J.; Beech, M.; Brosch, N.; Clifton, S.;
Connors, M.; Cooke, B.; Goetz, P.; Gaines, J. K.; Gramer, L.; Gray,
J.; Hildebrand, A. R.; Jewell, D.; Jones, A.; Leake, M.; LeBlanc,
A. G.; Looper, J. K.; McIntosh, B. A.; Montague, T.; Morrow, M. J.;
Murray, I. S.; Nikolova, S.; Robichaud, J.; Spondor, R.; Talarico,
J.; Theijsmeijer, C.; Tilton, B.; Treu, M.; Vachon, C.; Webster,
A. R.; Weryk, R.; Worden, S. P.
1998EM&P...82..167B Altcode: 2000EM&P...82..167B
No abstract at ADS

---------------------------------------------------------
Title: USAF Perspectives on Leonid Threat and Data Gathering Campaigns
Authors: Treu, Marvin H.; Worden, Simon P.; Bedard, Michael G.;
Bartlett, Randall K.
1998EM&P...82...27T Altcode: 2000EM&P...82...27T
The Air Force has long recognized the threat posed by the space
environment to military satellite systems including the potential for
disastrous effects resulting from a meteoroid impact. This concern
has steadily elevated with our nation's increasing reliance on space
assets for systems critical to national defense. The 1998/1999 Leonid
Meteor Storm Operational Monitoring Program was initiated to address
this threat. The goal of this Air Force-led, international cooperative
program was to provide near real-time Leonid meteor flux measurements
to satellite operators. The incorporation of these measurements with
model predictions provided an approximate 2-hour lead warning of the
peak storm activity, permitting satellite operators ample opportunity
to exercise hazard mitigation procedures. As a result, Department of
Defense (DoD) and other participating satellite operators may have
helped avoid spacecraft damage. The extent of any minor damage to
components impossible to detect by operators is difficult to ascertain
and may not manifest itself for a period of time. Modest micrometeoroid
precipitation may reduce spacecraft life expectancies as a consequence
of the physical erosion or sandblasting of exterior surfaces, and damage
sustained by electronic systems from concurrent high-energy plasma
discharges. Later effects could take the form of premature failure of
satellite sensors and other spacecraft components, leading to overall
shortening of satellite mission duration. The Air Force intends to
pursue further analysis of data and polling of satellite operators to
fully assess the Leonid '99 event. Future U.S. Air Force involvement
may include support for additional observations and analysis.

---------------------------------------------------------
Title: Differential accelerometer testing
Authors: Sapilewski, G.; Worden, P.; Bye, M.
1996CQGra..13A.165S Altcode:
Ground-based testing and qualification of the STEP differential
accelerometers is important for instrument development and overall
mission success. A facility for testing the various subsystems of
the flight accelerometer, including the superconducting magnetic
bearings, is under development at Stanford University. Achieving the
required sensitivity led to the development of an apparatus comprising
cryogenics, a multiple degree-of-freedom tipper table, an active control
system, electrostatic suspension and a capacitive sensing system.

---------------------------------------------------------
Title: Accelerometer development at Stanford
Authors: Worden, P. W.; Bye, M.
1996CQGra..13A.155W Altcode:
Preflight prototype differential accelerometers for STEP are being
developed at Stanford under NASA funding. Subsystem development in
progress includes work on thin-film superconducting circuits deposited
on cylinders, SQUID-based superconducting position measurement and
electrostatic positioning and charge control. A thorough programme
of testing and qualification of the subsystems is an essential part
of the experiment. We have built a flux microscope and magnetometer
probe to study magnetic flux motion, one of the limiting factors in
the accelerometers; a position sensor study facility; a tipper table
for testing and qualification of bearings in three degrees of freedom
and a `mechatronics' lab for the manufacture of critical circuits
on cylinders.

---------------------------------------------------------
Title: Detection of Meteoroid Impacts by Optical Sensors in Earth
Orbit
Authors: Tagliaferri, E.; Spalding, R.; Jacobs, C.; Worden, S. P.;
Erlich, A.
1994hdtc.conf..199T Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Technical challenges of Satellite Test of the Equivalence
Principle mission.
Authors: Mason, P. V.; Israelsson, U. E.; Petrac, D.; Jackson, H. W.;
Worden, P.; Parmley, R.
1993Cryo...33..390M Altcode:
The Satellite Test of the Equivalence Principle (STEP) experiment
is being proposed to improve our knowledge of the equivalence of
inertial and gravitational mass by a factor of 106,
yielding a crucial test of one of the fundamental postulates of
Einstein's theory of general relativity. The experiment will use six
differential superconducting accelerometers in a spacecraft in low
Earth orbit. The accelerometers will each contain two proof masses
of different densities. If the equivalence principle is violated,
the masses will oscillate with respect to each other at the orbital
frequency. The mission will last six months and is planned for launch
in 2000. The entire experiment must be cooled to 1.8K and must be
held to this level within 1mK per orbit. A crucial requirement is that
any disturbances in the orbital frequency must generate gravitational
variation signals much less than the expected signal. One source of
such disturbance is the motion of the liquid helium in the local gravity
gradient field, which rotates at orbital frequency with respect to the
spacecraft. An electrostatic confinement system has been proposed for
this purpose. This system will be described. A back-up system using
the superfluid fountain effect will also be discussed.

---------------------------------------------------------
Title: Satellite test of the equivalence principle.
Authors: Worden, P. W., Jr.
1993rges.conf...43W Altcode: 1993rges.rept...43W
The essential features of an orbiting equivalence principle
experiment (STEP) are described. In addition to a test of this
fundamental principle to one part in 1017, the instrument
makes possible an improved measurement of the gravitational constant,
improved geodetic measurements of the Earth, aeronomy measurements with
high sensitivity and time resolution, and an engineering evaluation
for further development of drag-free spacecraft.

---------------------------------------------------------
Title: Spectroscopic and Photometric Observations of a Five-Magnitude
Flare Event on UV CETI
Authors: Eason, Erik L. E.; Giampapa, M. S.; Radick, R. R.; Worden,
S. P.; Hege, E. K.
1992AJ....104.1161E Altcode:
Optical observations of a 5-mag flare in the U band on UV Ceti (dM5.6e)
at both spectral and temporal resolutions are presented. A strong
violet continuum which cannot be reproduced solely with a thermal
bremsstrahlung spectrum is seen. The energy emitted by the flare in the
U band is about 5.0 x 10 exp 31 ergs. The corresponding total flare
energy in white light is estimated to be 1.2 x 10 exp 32 ergs. This
estimate, combined with the 700-s duration of the U-band event, yields
an average white-light flare luminosity which is about 3 percent of
the quiescent stellar bolometric luminosity. Strong H-alpha wings
appeared after the impulsive phase. A discernible central reversal
is present in both the quiescent H-alpha profile and, significantly,
in the flare profile following the impulsive phase. It is suggested
that the site of H-alpha flare emission is not necessarily associated
with a compact, high pressure region. The flare-enhanced line emission
arises from large flare volumes that are, in turn, a distinguishing
feature of stellar flares of this magnitude.

---------------------------------------------------------
Title: Remote Sensing: The Inconsistency of U. S. Space Policy
Authors: Worden, Simon P.; Katz, Jordan S.
1992PrAA..144..369W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: On Self-Licking Ice Cream Cones
Authors: Worden, S. P.
1992ASPC...26..599W Altcode: 1992csss....7..599W
No abstract at ADS

---------------------------------------------------------
Title: STEP. A Satellite Test of the Equivalence Principle.
Authors: Reinhard, R.; Worden, P. W.; Everitt, C. W. F.
1991EN.....22..216R Altcode:
STEP aims to determine any difference in the rate of fall of test
masses in an Earth-orbiting satellite to one part in 1017
of the total gravitational acceleration - a 106 factor
improvement over existing measurements.

---------------------------------------------------------
Title: Gradiometry coexperiments to the gravity probe B and step
missions
Authors: Tapley, M.; Breakwell, J.; Everitt, C. W. F.; van Patten,
R.; Worden, P.
1991AdSpR..11f.179T Altcode: 1991AdSpR..11..179T
The Gravity Probe B spacecraft, designed to test predictions of
general relativity, will fly in the mid 1990's. It will carry four
electrostatically suspended gyroscopes in a cryogenic environment
and will have a drag-free control system to minimize disturbances
on the gyroscopes. The Stanford Test of Equivalence Principle (STEP)
spacecraft, to fly later, will carry a set of test masses under very
similar conditions. This paper explores the possibility of using
differential measurements of the GP-B gyroscope suspension forces and
the STEP test mass displacement readout to form single-axis gravity
gradiometers. We show that the noise in the suspension systems is
sufficiently small in the relevant frequency range, and that enough
information is collected to compensate for the spacecrafts' attitude
motion. Finally, using Breakwell's “flat-earth” approximation, we
compare these experiments to other geodesy experiments and predict the
contribution they can make to the knowledge of the Earth's geopotential.

---------------------------------------------------------
Title: a Satellite Test of the Equivalence Principle
Authors: Worden, P. W., Jr.
1989grg..conf..542W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Almost exactly Zero: the equivalence principle.
Authors: Worden, P. W., Jr.
1988nznf.conf..766W Altcode:
Contents: 1. Introduction: the equivalence principle; conceptual
development and historical background. 2. The orbital experiment. 3. The
ground-based experiment: general description; period matching and
position subtraction; magnetic bearing; position detectors; a 200 m
pendulum. 4. Status and conclusion.

---------------------------------------------------------
Title: Why Astronomers Should Love Sdi
Authors: Worden, S. P.
1987S&T....74..340W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Magnetic Field Measurements on the Sun and Implications for
Stellar Magnetic Field Observations
Authors: Sun, Wei-Hsin; Giampapa, Mark S.; Worden, Simon P.
1987ApJ...312..930S Altcode:
Results of solar magnetic field measurements in plages, sunspot umbrae,
and sunspot penumbrae using high spectral resolution, unpolarized
infrared H band spectral data are presented. A Fourier deconvolution
analysis scheme similar to that utilized for stellar magnetic field
measurements is adopted. As an example, a field strength of 3240 + or -
450 G is determined in a sunspot umbra combined with a value of 2000 +
or - 180 G in the associated penumbra. These values are compared with a
direct measurement of the spot umbra and penumbra field strengths based
on the observed separation of the Zeeman components of the magnetically
sensitive lines. Possible origins for the discrepancy between the
results inferred by these two different techniques are discussed. The
Fourier analysis results confirm the widespread occurrence of kilogauss
level fields in the solar photosphere. The implications of the solar
results for stellar magnetic field measurements are considered.

---------------------------------------------------------
Title: Coordinated Magnetic and Chromospheric/Coronal Synoptic
Observations
Authors: Worden, Simon P.
1984iue..prop.1906W Altcode:
We propose to obtain time-resolved, coordinated observations of magnetic
flux and the associated coronal emission as well as chromospheric and
transition region line emission for selected active chromospheric
stars. The unique data to be obtained in this program will provide
a crucial input to theories that describe the heating of stellar
chromospheres and coronae. In essence, the results to be acquired
through the observations will establish a preliminary empirical
relationship between stellar photospheric magnetic field strengths
and magnetic flux, stellar coronal field strength and emission, and
stellar outer atmospheric line emission. We are presently utilizing
demonstrated methods to directly detect magnetic fields on stellar
surfaces. We are also able to deduce coronal field strengths from
X-ray or radio observations. Magnetic results indicate the existence of
strong (a few kilogauss) fields that may cover up to 80% of the stellar
surface. Moreover, these fields are observed to rapidly (2-3 days) vary
in surface coverage, suggesting a single large magnetic spot complex
on only one hemisphere of the star. We therefore propose a coordinated
IUE ground-based synoptic program to obtain chromospheric-transition
region data (with IUE), and photospheric and coronal magnetic field and
flux measurements (ground-based observations) for several stars that
exhibit rapidly varying surface field coverages over their rotational
periods. Our IUE observing pattern will primarily consist of low
dispersion, SWP observations and high-dispersion, LWR exposures. These
data will be obtained simultaneously (or near simultaneously) with
ground-based optical, IR and radio observations. The ground-based
data will be used to infer magnetic field strengths and flux in
the photosphere and corona. We also require that the IUE shifts be
scheduled every third day to insure that we examine the entire stellar
surface over 10-15 day rotational periods. We require two separate
observing periods in order to access all objects in the target list
from ground-based observing sites.

---------------------------------------------------------
Title: A photometric study of the cataclysmic variable, LX Serpentis.
Authors: Eason, E. L. E.; Worden, S. P.; Klimke, A.; Africano, J. L.
1984PASP...96..372E Altcode:
A high-speed photometric study of the cataclysmic variable star
LX Serpentis has been performed, using a 1.2 m synoptic telescope
in white light. By means of a second-order least squares fitting
of the eclipse times, an orbital period of about 0.158 hr was
derived. The shapes of the eclipse light curves indicate that the
hot-spot brightness morphology can be irregular, and it can change
in a time scale of days. An analysis of the power-spectrum reveals
a low signal-to-noise ratio peak at about 0.007 Hz (about 140 sec),
but in general no evidence was found for periodic or quasi-periodic
oscillations in the power spectrum.

---------------------------------------------------------
Title: The response of chromospheric emission lines to flares on YZ
Canis Minoris.
Authors: Worden, S. P.; Schneeberger, T. J.; Giampapa, M. S.; Deluca,
E. E.; Cram, L. E.
1984ApJ...276..270W Altcode:
Six flares of the dMe star YZ CMi have been observed with simultaneous
photometry and high-dispersion, time-resolved spectroscopy.The spectra
have temporal resolutions of 3 minutes with spectral resolutions
of 0.24 Å. The largest observed flare had a U band amplitude of
1.5 mag. Hα and Hβ line profiles did not broaden during any of the
observed flares, although the line center intensity increased by over a
factor of 2 during some flares. After the initial increase in intensity,
the emission line strength decreases but remains at enhanced levels
for hours following U band flares. The Hα flare luminosity and total
energy are compared to corresponding properties of solar flares.

---------------------------------------------------------
Title: Variations in the solar calcium K line 1976-1982
Authors: Keil, S. L.; Worden, S. P.
1984ApJ...276..766K Altcode:
Chromospheric variability between 1976 and 1982 as evidenced in Ca
II K line observations obtained at Sacramento Peak Observatory is
reported. The data on solar variability are compared to similar data
collected at Kitt Peak by White and Livingston (1981). The measurement
of solar rotation as reflected in the K index was attempted. Partial
success was achieved in this second objective, based on limited
results in early 1977 and early 1981-1982. While there is good long
term (about 6 months) correlation between the K line and the number
of plages and sunspots during the rising phase of solar activity,
the short term correlation (about 1 week) is poor.

---------------------------------------------------------
Title: High-speed digital signal processing for speckle
interferometry.
Authors: Hege, E. K.; Cocke, W. J.; Strittmatter, P. A.; Worden,
S. P.; Booth, W. C.
1984SPIE..445..469H Altcode:
Speckle interferometry has now been shown capable of yielding
diffraction limited information on objects as faint as visual
magnitude 16. The instrumentation proposed will improve spatial
resolution at visible wavelengths to approximately 15 milliarc-seconds
(75×10-9radians, the best possible for any existing
telescope), reduce detector induced image distortion to less than 1%
and increase the throughput to essentially real-time complex Fourier
transform amplitude and phase integrations at the telescope.

---------------------------------------------------------
Title: Magnetic Field Measurements on the Sun and Synthesis of
Stellar Spectrum from Solar Data
Authors: Sun, W.; Giampapa, M. S.; Worden, S. P.
1983BAAS...15..952S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The photometric variability of solar-type stars. III. Results
from 1981-82, including parallel observations of thirty-six Hyades
stars.
Authors: Radick, R. R.; Mihalas, D.; Lockwood, G. W.; Thompson,
D. T.; Warnock, A., III; Hartmann, L. W.; Worden, S. P.; Henry, G. W.;
Sherlin, J. M.
1983PASP...95..621R Altcode:
A photometric survey of main-sequence stars in the Pleiades, Hyades,
and Malmquist Field, to investigate variability among solar-type
stars, had been continued at Cloudcroft Observatory for a second
season. Possibly six of 40 Pleiades stars, two (possibly six) of 49
Hyades stars and possibly four of 42 stars in the Malmquist Field
are found to be variable. Parallel observations of Hyades stars were
obtained also at Lowell Observatory. These measurements, which achieved
better precision, reveal significiant variations in eleven (possibly 16)
of 36 Hyades stars, all of spectral type F7 V-K2 V. Agreement between
the two surveys is acceptable. The two seasons of the Cloudcroft survey
show that changes in the mean annual brightness of the Hyades stars
accompany changes in the amplitude of their short-term variability,
in the sense that a star tends to become fainter as its variability
increases and vice versa. Color effects are absent.

---------------------------------------------------------
Title: The photometric variability of solar-type stars. II. Stars
selected from Wilson's chromospheric activity survey.
Authors: Radick, R. R.; Wilkerson, M. S.; Worden, S. P.; Africano,
J. L.; Klimke, A.; Ruden, S.; Rogers, W.; Armandroff, T. E.; Giampapa,
M. S.
1983PASP...95..300R Altcode:
The authors have observed eleven solar-type main-sequence stars to
search for continuum variability. Stars were selected from Wilson's
chromospheric activity survey, and were observed for periods of three
to six months with intermediate-band Stroemgren uvby photometry. The
authors find evidence that two of these eleven stars are variable
and that one other may be. Comparison with contemporaneous Ca II H +
K emission flux measurements shows that the amplitude of photometric
variability correlates strongly with both the mean emission flux
and the amplitude of its variation. Variations in continuum light and
emission flux tend to correlate in time, as well, with continuum minima
coinciding with emission maxima and vice-versa. The authors infer that
the surface activity of these stars tends to be confined to localized
activity centers that include both emission plages and dark spots,
similar to the active regions observed on the sun.

---------------------------------------------------------
Title: The magnetic field on the RS Canum Venaticorum star lambda
Andromeda.
Authors: Giampapa, M. S.; Golub, L.; Worden, S. P.
1983ApJ...268L.121G Altcode:
A program to detect and measure magnetic flux on the surfaces of
late-type stars is discussed. A technique is adopted to deconvolve
magnetically insensitive lines from similar, magnetically sensitive
lines to infer the degree of Zeeman splitting in the latter lines. These
measurements yield values for the magnetic field strength and filling
factor (flux). To illustrate the approach, observations of the RS
CVn star Lambda And are presented. At the epoch of observation, 1981
April 26, a field strength of 1290 + or - 320 gauss covering 48 + or -
7 percent of this star's surface is found. This measurement compares
with an estimate of coronal magnetic flux in the cooler component of
the stellar corona of 1110 gauss with a coronal volume filling factor
of 75 percent, based on X-ray data for Lambda And.

---------------------------------------------------------
Title: Using small aperture interferometry to detect planets in
nearby binary star systems
Authors: Currie, D. G.; McAlister, H. A.; Schneeberger, T. J.; Worden,
S. P.
1983STIN...8331551C Altcode:
If suitably accurate binary star orbits can be observed, the effects of
planets in the binary star system may be detectable in the reflex motion
of the component binary stars. We show that interferometric measurements
of binary star systems will provide this information. We discuss the
effects of the atmosphere on degrading images and how interferometry
will remove these effects to provide very accurate binary star positions
relative to the other components in the binary system. Two systems,
amplitude interferometry and speckle interferometry, can accomplish
this using existing telescopes and techniques. With these methods,
nearly accuracies of 0.00002 arc second are possible for binaries of 1
arc second separation and 10000 arc second for a 5 arc binary. These
accuracies are more than enough to detect planets in orbits like
Jupiter's out to over 20 pc. There are 188 observable systems within
20 pc, in most of which it is possible to have stable planetary orbits
similar to solar system orbits. With advanced data recording systems it
is possible to observe binary systems where the components are as faint
as +16 stellar magnitudes. A dedicated 2-meter interferometric telescope
to monitor binary stars could be built for about 1.4 million dollars.

---------------------------------------------------------
Title: Stellar and Planetary Photometry at Cloudcroft Observatory
Authors: Worden, S. P.
1983IAPPP...9..120W Altcode:
For the last four years there has been an extensive program at the
Cloudcroft 48 inch photometric observatory to study the question of
luminosity variability in the sun and solar-type stars. The author
gives a summary of this program's results and urges small photoelectric
observatory to consider assisting in this program.

---------------------------------------------------------
Title: Eclipse timings in U Geminorum.
Authors: Eason, E. L. E.; Africano, J. L.; Klimke, A.; Quigley, R. J.;
Rogers, W.; Worden, S. P.
1983PASP...95...58E Altcode:
Seventeen new timings of primary eclipse minimum for the dwarf nova,
U Gem, are reported. The orbital period of the binary system is seen as
quasi-periodic. Among the possible causes of the ephemeris variability
are nonconservative mass transfer, nonconservation of orbital angular
momentum, the relative motion of the hot spot within the system, apsidal
motion, and the existence of a third star. U Gem is found to exhibit
the following interesting features: flickering (indicating possible
spasmodic mass transfer); the probable existence of a disk, allowing
storage of considerable rotational angular momentum; occasional swelling
of the disk, suggesting variable momentum storage; and outbursts.

---------------------------------------------------------
Title: Methods and results for detecting magnetic fields on late-type
stars.
Authors: Giampapa, M. S.; Worden, S. P.
1983IAUS..102...29G Altcode:
A program to detect and measure magnetic flux on the surfaces of
late-type stars is discussed. A novel technique is adopted to deconvolve
magnetically insensitive lines from similar, magnetically sensitive
lines to infer the degree of Zeeman splitting in the latter lines. These
measurements yield values for the magnetic field strength and filling
factor (flux). To illustrate the approach multiple observations are
presented of the RS CVn star Lambda And. At the epoch of observation
26 April 1981 a field strength of 1290 + or - 50 gauss covering 48 +
or - 2 percent of this stars's surface is found. Observations at other
epochs clearly demonstrate magnetic flux variability on Lambda And.

---------------------------------------------------------
Title: Optical and ultraviolet stellar flare spectroscopy
Authors: Worden, S. P.
1983ASSL..102..207W Altcode: 1983ards.proc..207W; 1983IAUCo..71..207W
As for solar flares, one of the most physically revealing types of
data for M-dwarf flares are high-resolution, time-resolved spectra. Due
to the intrinsically faint nature of the M-dwarf stars, spectroscopic
data has tended to be of low spectral (approximately 5 A) and temporal
(approximately 5 min) resolution. However, with the development of
image intensified spectrographs and fast, efficient digital detectors,
the last several years have seen the successful acquisition of both high
time and spectral resolution M-dwarf flare spectra. Recent programs have
also been successfully conducted using the International Ultraviolet
Explorer satellite to obtain UV and EUV spectra of M-dwarf flares. These
data reveal that dwarf M star flares are remarkably similar to solar
flares in all aspects of their spectroscopic phenomenology.

---------------------------------------------------------
Title: Cryogenic Equivalence Principle Experiment: discussion and
present status.
Authors: Worden, P. W., Jr.
1983mgm..conf..771W Altcode:
The Weak Equivalence Principle is the hypothesis that the ratio of
passive gravitational mass to inertial mass is the same for all bodies
regardless of their composition. This principle has a fundamental
place in physics as the experimental basis for Einstein's Strong
Equivalence Principle, which is a postulate of General Relativity. This
paper describes the present state of the Stanford Orbital Equivalence
Principle Experiment.

---------------------------------------------------------
Title: The photometric variability of solar-type stars. I. Preliminary
results for the Pleiades, Hyades and the Malmquist field.
Authors: Radick, R. R.; Hartmann, L.; Mihalas, D.; Worden, S. P.;
Africano, J. L.; Klimke, A.; Tyson, E. T.
1982PASP...94..934R Altcode:
The young main sequence stars in the Pleiades and Hyades clusters, and
old disk stars in the Malmquist Field near the north galactic pole,
have been observed by precision photometry in order to determine
the prevalance of variability among solar type stars. Significant
variations have been found in at least five, and possibly ten, of 44
Hyades stars, and possibly one of the 41 stars in the Malmquist Field,
all of which are of spectral type F8 V-K2 V.

---------------------------------------------------------
Title: Outer atmospheres of cool stars. XII. A survey of IUE
ultraviolet emission line spectra of cool dwarf stars.
Authors: Linsky, J. L.; Bornmann, P. L.; Carpenter, K. G.; Wing,
R. F.; Giampapa, M. S.; Worden, S. P.; Hege, E. K.
1982ApJ...260..670L Altcode:
Quantitative information is obtained on the chromospheres and
transition regions of M dwarf stars, in order to determine how the outer
atmospheres of dMe stars differ from dM stars and how they compare with
the outer atmospheres of quiet and active G and K type dwarfs. IUE
spectra of six dMe and four dM stars, together with ground-based
photometry and spectroscopy of the Balmer and Ca II H and K lines,
show no evidence of flares. It is concluded, regarding the quiescent
behavior of these stars, that emission-line spectra resemble that of
the sun and contain emission lines formed in regions with 4000-20,000 K
temperatures that are presumably analogous to the solar chromosphere,
as well as regions with temperatures of 20,000-200,000 K that are
presumably analogous to the solar transition region. Emission-line
surface fluxes are proportional to the emission measure over the range
of temperatures at which the lines are formed.

---------------------------------------------------------
Title: Stellar model chromospheres. XIII. M dwarf stars.
Authors: Giampapa, M. S.; Worden, S. P.; Linsky, J. L.
1982ApJ...258..740G Altcode:
Single-component, homogeneous model chromospheres that are consistent
with high-resolution profiles of the Ca II K line calibrated in surface
flux units for three dMe and 2 dM stars observed at quiescent times
are constructed. The models reveal several systematic trends. Large
values of the ratio of T(min) to T(eff) are derived, indicating a large
amount of nonradiative heating present in the upper photospheres of M
dwarf stars. It is also found that the lower chromospheric temperature
gradient is similar for all the M dwarf stars. Since for the models here
the chromospheric K line emission strength is most sensitive to the
total amount of chromospheric material present within the approximate
temperature range T(min)-6000 K, increasing the emission strength is not
simply due to increasing chromospheric temperature gradients. It is also
found that both the electron density and electron temperature at one
thermalization length in the K line below the top of the chromospheres
are greater in the dMe stars than in the dM stars. The M dwarf models
here have microturbulent velocities between 1 and 2 km/sec, which are
much smaller than for solar chromosphere models.

---------------------------------------------------------
Title: Speckle interferometric observations of Pluto and Charon
Authors: Hege, E. K.; Hubbard, E. N.; Drummond, J. D.; Strittmatter,
P. A.; Worden, S. P.; Lauer, T.
1982Icar...50...72H Altcode:
We report speckle interferometric observations of Pluto and its
moon (1978 P1) Charon obtained on 5 June 1980 with a single 1.8-m
mirror of the Multiple Mirror Telescope. Our observations yield a
separation of 0″.31 (±0″.05) between Pluto and Charon at position
angle 285° (±7°) for JD 2444395.75. This result and other direct
observations indicate an adjustment of +4.0 hr to the orbital epoch of
R. S. Harrington and J. W. Christy [ Astron.J.86, 442-443 (1981)]. Our
observation, which represents the first resolution of the system near
minimum separation, also suggests that the inclination of the orbit to
the plane of the sky should be increased by 3°; this will delay the
onset of the predicted eclipsee season by one apparition to 1984 or
1985. Our data are consistent with Pluto diameter 0″.14 (±0″.02)
= 3000 (±400) km and Charon diameter 0″..05 (±0″.03) = 1100
(±600) km.

---------------------------------------------------------
Title: Solar Rotation and Variability Observed in the Ca II K Line
Authors: Keil, S. L.; Worden, S. P.
1982BAAS...14..623K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: High-speed photometry of the cepheid TT Aql.
Authors: Connolly, L. P.; Africano, J. L.; Klimke, A.; Worden, S. P.
1982PASP...94..182C Altcode:
High-speed differential photometry is presented for the classical
Cepheid TT Aql. There is good coverage over most phases of the light
curve. An irregularity in the light curve during the ascending branch
stand-still is possibly identified. The period for this Cepheid is
briefly discussed.

---------------------------------------------------------
Title: A heating mechanism for the chromospheres of M dwarf stars.
Authors: Giampapa, M. S.; Golub, L.; Rosner, R.; Vaiana, G. S.;
Linsky, J. L.; Worden, S. P.
1982SAOSR.392A..73G Altcode: 1982csss....2...73G
The atmospheric structure of the dwarf M-stars which is especially
important to the general field of stellar chromospheres and coronae
was investigated. The M-dwarf stars constitute a class of objects
for which the discrepancy between the predictions of the acoustic
wave chromospheric/coronal heating hypothesis and the observations is
most vivid. It is assumed that they represent a class of stars where
alternative atmospheric heating mechanisms, presumably magnetically
related, are most clearly manifested. Ascertainment of the validity
of a hypothesis to account for the origin of the chromospheric and
transition region line emission in M-dwarf stars is proposed.

---------------------------------------------------------
Title: An Air Force/NSF initiative to study the origins of solar
activity.
Authors: Worden, S. P.; Dunn, R. B.; Smith, M. A.; Zirker, J. B.
1982SAOSR.392B.221W Altcode: 1982csss....2..221W
No abstract at ADS

---------------------------------------------------------
Title: Coordinated X-ray, optical and radio observations of flaring
activityon YZ Canis Minoris.
Authors: Kahler, S.; Golub, L.; Harnden, F. R.; Liller, W.; Seward,
F.; Vaiana, G.; Lovell, B.; Davis, R. J.; Spencer, R. E.; Whitehouse,
D. R.; Feldman, P. A.; Viner, M. R.; Leslie, B.; Kahn, S. M.; Mason,
K. O.; Davis, M. M.; Crannell, C. J.; Hobbs, R. W.; Schneeberger,
T. J.; Worden, S. P.; Schommer, R. A.; Vogt, S. S.; Pettersen, B. R.;
Coleman, G. D.; Karpen, J. T.; Giampapa, M. S.; Hege, E. K.; Pazzani,
V.; Rodono, M.; Romeo, G.; Chugainov, P. F.
1982ApJ...252..239K Altcode:
The YZ Canis Minoris (Gliese 285), a late-type dwarf star with
Balmer emission (dM4.5e), is a member of the UV Ceti class of flare
stars. Obtaining good X-ray observations of a dMe star flare is
important not only for understanding the physics of flares but also for
testing current ideas regarding the similarity between stellar and solar
flares. The Einstein X-ray Observatory has made it possible to conduct
X-ray observations of dMe stars with unprecedented sensitivity. A
description is presented of the results of a program of ground-based
optical and radio observations of YZ CMi coordinated with those of
the Einstein Observatory. The observations were carried out as part
of a coordinated program on October 25, 26, and 27, 1979, when YZ CMi
was on the dawn side of the earth. Comprehensive observational data
were obtained of an event detected in all three wavelength regions on
October 25, 1979.

---------------------------------------------------------
Title: Speckle interferometry with the Multiple Mirror Telescope.
Authors: Hege, E. K.; McCarthy, D. D.; Strittmatter, P. A.; Worden,
S. P.; Lowe, F. J.
1982JOSA...72.1759H Altcode: 1982OSAJ...72.1759H
No abstract at ADS

---------------------------------------------------------
Title: A preflare diminution in the quiescent flux of EQ Pegasi.
Authors: Giampapa, M. S.; Africano, J. L.; Klimke, A.; Parks, J.;
Quigley, R. J.; Robinson, R. D.; Worden, S. P.
1982ApJ...252L..39G Altcode:
The occurrence of a remarkable flare event on EQ Peg is reported as
recorded by high speed photometry in the Johnson U band: a stellar
flare event is immediately preceded by a well-defined decline in
the quiescent flux of the star. The U band flux decays to a minimum
level that is 75% of the stellar quiescent flux, and the duration of
the so-called negative flare event is 2.7 minutes. A description of
the observation is presented and hypotheses are discussed that may
eventually account for this phenomenon.

---------------------------------------------------------
Title: The AFGL image reconstruction program 2 speckle interferometry
Authors: Worden, S. P.; Hege, E. K.; Hubbard, E. N.; Woolf, N. J.;
Strittmatter, P. A.
1981afhr.rept.....W Altcode:
Recent work indicates that large-telescope, optics-limited images are
recoverable for objects as faint as +15 stellar magnitudes using a
technique called speckle interferometry. This report presents a review
of speckle interferometry, including current status and results. Section
2 provides a background of the Fourier mathematics used in image
processing and optical systems. Section 3 describes how the atmosphere
degrades astronomical images and how speckle interferometry has been
used to recover high-resolution detail. Section 4 describes new work
to recover actual optics-limited images, and compares active optics
systems with speckle interferometry.

---------------------------------------------------------
Title: Speckle interferometry observations of the triple QSO PG
1115+08.
Authors: Hege, E. K.; Hubbard, E. N.; Strittmatter, P. A.; Worden,
S. P.
1981ApJ...248L...1H Altcode:
Speckle interferometric observations of the 16.2 mag component A of PG
1115 + 08 show that it is resolved into two components, separated by
0.54 arcsec in position angle 20 deg. The data suggest that the two
components are approximately equally bright and are unresolved at a
resolution of approximately 0.15 arcsec. These results are consistent
with those inferred from long exposure images.

---------------------------------------------------------
Title: High-resolution profiles of chromospheric lines in M dwarf
stars.
Authors: Worden, S. P.; Schneeberger, T. J.; Giampapa, M. S.
1981ApJS...46..159W Altcode:
Forty-six hydrogen and sodium line profiles are presented for 17
selected dwarf M and dwarf M emission line stars. These profiles,
derived from echelle spectrograms, typically have 0.25 A spectral
resolution. Most of the dMe stars show hydrogen emission lines with
central reversals. Central emission features in the cores of the Na D
lines are often observed, and the presence of these emission features
is strongly correlated with hydrogen line emission.

---------------------------------------------------------
Title: Stellar model chromospheres. XII. High-resolution, absolute
flux profiles of the CaII H and K lines in dMe and non-dMe stars.
Authors: Giampapa, M. S.; Worden, S. P.; Schneeberger, T. J.; Cram,
L. E.
1981ApJ...246..502G Altcode:
We present 142 mÅ resolution spectra of the cores and wings of the
Ca II H and K lines in three dMe and four comparison dwarf M stars,
obtained with the KPNO 4 m echelle spectrograph and blue image
tube. The narrow-band photometry of Willstrop and the Barnes and
Evans relations for stellar angular diameters convert the observed
relative flux to absolute surface flux units with an estimated
uncertainty of ± 15 %. We derive chromospheric radiative loss rates
in the H and K lines and discuss trends in these loss rates with
effective temperature. Monochromatic surface fluxes are tabulated for
different features in the H and K lines, and radiation temperatures
are derived from the mean surface fluxes at K1 and
H1, respectively. We find TR(H1) &gt;
TR(K1), consistent with partial redistribution
theory. The TR(K1)/Teff ratio
is higher in these M dwarfs than the giants studied in Paper X,
and it is anomalously high for the dMe flare star YZ CMi. If
TR(K1)/Teff is an empirical age
indicator, then the result for YZ CMi implies that flare activity
and youth are directly correlated, as has been suggested by other
investigators. Moreover, the result implies that a high degree of
nonradiative heating is present in the upper photospheres of dMe
stars. Measurements of line widths at H1 and K1
are presented together with FWHM data for the H and K lines. We find
that the scaling law proposed by Ayres generally agrees with the
observed trend exhibited by the K1 widths. We also discuss
chromospheric radiative loss rates in the Hɛ line compared with loss
rates in the H and K lines, and present corrected FWHM(K) widths and
compare them to the widths predicted by the Wilson-Bappu relation as
calibrated by Lutz.

---------------------------------------------------------
Title: Possible radio flaring activity on a late-type giant star,
alf Cet.
Authors: Boice, D. C.; Kuhn, J. R.; Robinson, R. D.; Worden, S. P.
1981ApJ...245L..71B Altcode:
A search is made for radio flare events on 15 late-type stars using the
Arecibo radio telescope at 430 MHz. About 50 hr of interference-free
data are obtained and one impulsive event is detected for the M2
III star Alpha Cet. The observed radio event is consistent with the
hypothesis that it originated in a solar-flare-type disturbance in
the stellar atmosphere.

---------------------------------------------------------
Title: Flare activity on T Tau stars.
Authors: Worden, S. P.; Schneeberger, T. J.; Kuhn, J. R.; Africano,
J. L.
1981ApJ...244..520W Altcode:
Observations of short-period photometric fluctuations in T Tauri
stars show flarelike events. These events are consistent with the
superposition of many solar-like flare events and have a power-spectrum
frequency dependence of ∼f-2. This dependence is the same
as that observed on UV Ceti stars. The flare events are very powerful,
and the expected proton flux from these events may explain early solar
system abundance anomalies without recourse to nearby supernovae. The
flare events are consistent with the observations of mass loss in
these stars.

---------------------------------------------------------
Title: Recent Interferometric Results
Authors: Worden, S.
1981siwn.conf..443W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Photometric Variability of Main Sequence Stars
Authors: Radick, R. R.; Hartmann, L. W.; Mihalas, D. M.; Worden, S. P.
1981BAAS...13R.832R Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Recent Results in Observing Solar Phenomena in Stars
Authors: Worden, S.
1981siwn.conf..201W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Detecting Planets in Binary Systems with Speckle Interferometry
Authors: Worden, S. P.
1981NASCP2156..177W Altcode: 1981litu.conf..177W
The potential of speckle interferometry in the astrometric detection
of stellar motions due to the presence of planetary bodies in binary
star systems is discussed. Sources of atmospheric image degradation
are considered, and the principles of speckle interferometry,
which acts to eliminate atmospheric effects by the correlation of
short-exposure photographs, are outlined. Instruments used in speckle
interferometry are discussed, and data reduction techniques, involving
Fourier transformations and the removal of residual seeing effects, are
indicated. Experience in the speckle interferometry of binary systems
is presented which has shown errors due to uncertainty in the data
to be + or - 0.3% in separation and + or - 0.2 deg in position angle
for each 50-frame data set. A set of possible binary star systems to
be included in a search for planetary systems is examined, and it is
shown that about half of these nearby systems should have stable orbits
for a Jovian planet, which should be detectable within the accuracies
possible for speckle interferometry.

---------------------------------------------------------
Title: The Mg II h and k lines in a sample of dMe and dM stars.
Authors: Giampapa, M. S.; Pornmann, P. L.; Ayres, T. R.; Linsky,
J. L.; Worden, S. P.
1981NASCP2171..279G Altcode: 1981uviu.nasa..279G; 1981NASCP3171..279G; 1980IUE80......279G
Both Mg II h and k line fluxes are presented for a sample of 4 dMe and
3 dM stars obtained with the IUE satellite in the long wavelength,
low dispersion mode. The observed fluxes are converted to stellar
surface flux units and the importance of chromospheric non radiative
heating in this sample of M dwarf stars is intercompared. In addition,
the net chromospheric radiative losses due to the Ca II H and K lines in
those stars in the sample for which calibrated Ca II H and K line data
exist are compared. Active region filling factors which likely give
rise to the observed optical and ultraviolet chromospheric emission
are estimated. The implications of the results for homogeneous, single
component stellar model chromospheres analyses are discussed.

---------------------------------------------------------
Title: An image reconstruction for Capella with the Steward
Observatoty.
Authors: Cocke, W. J.; Hege, E. K.; Hubbard, E. N.; Strittmatter,
P. A.; Worden, S. P.
1983LowOB...9..159C Altcode: 1983LowOB.167..159C; 1981LowOB...9..159C; 1983IAUCo..62..159C
Since their invention in 1970, speckle interferometric techniques
have evolved from simple optical processing of photographic images
to high-speed digital processing of quantum-limited video data. Basic
speckle interferometric techniques are discussed, taking into account
the implementation of two distinct data-recording/data-processing
modes. A description of image reconstruction techniques is also
provided. Two methods for image phase retrieval have been implemented,
including a phase unwrapping method developed by Cocke (1980) and the
phase accumulation method of Knox and Thompson (1974). On February
3, 1981, analogue mode speckle interferograms for Capella and the
unresolved star Gamma Ori were obtained with both the phase-unwrapping
and the Knox-Thompson method.

---------------------------------------------------------
Title: UV chromospheric and circumstellar diagnostic features among
F supergiant stars.
Authors: Stencel, R. E.; Worden, S. P.; Giampapa, M. S.
1981NASCP2171..311S Altcode: 1981NASCP3171..311S; 1980IUE80......311S; 1981uviu.nasa..311S
A survey of F supergiant stars to evaluate the extension of
chromospheric and circumstellar characteristics commonly observed
in the slightly cooler G, K, and M supergiant is discussed. An
ultraviolet survey was elected since UV features of Mg II and Fe II
might persist in revealing outer atmosphere phenomena even among F
supergiants. The encompassed spectral types F0 to G0, and luminosity
classes Ib, Ia, and Ia-0. In addition, the usefulness of the emission
line width-to-luminosity correlation for the G-M stars in both the Ca
II and Mg II lines is examined.

---------------------------------------------------------
Title: Recovery of intensity information from speckle data.
Authors: Hege, E. K.; Hubbard, E. N.; Cocke, W. J.; Strittmatter,
P. A.; Worden, S. P.; Radick, R. R.
1983LowOB...9..185H Altcode: 1983IAUCo..62..185H; 1981LowOB...9..185H; 1983LowOB.167..185H
The present investigation is concerned with effects of instrumental
response and photon statistics, the so-called noise bias, and procedures
for correcting these effects in order to recover binary star relative
intensity information from speckle interferometric data. The intensity
retrieval problem is considered along with details regarding the
noise bias problem, complications which ultimately limit the accuracy
with which binary star intensity ratios may be determined, and some
preliminary results. Attention is given to calibration uncertainties,
position angle uncertainties, the observing band-pass, and the major
contributions to magnitude difference uncertainties.

---------------------------------------------------------
Title: The angular diameters of supergiant stars from speckle
interferometry.
Authors: Welter, G. L.; Worden, S. P.
1980ApJ...242..673W Altcode:
The Lynds et al (1976) image reconstruction algorithm is applied to
speckle interferometric data for the supergiant stars alpha Ori,
alpha Cet, alpha Tau, rho Per, and alpha Her. Further restoration
is applied to the images of alpha Ori and omicron Cet. Estimations
of angular diameter as a function of wavelength and limb darkening
are made, confirming the observation by Bonneau and Labeyrie (1973)
that such stars appear smaller at long wavelengths. An upper limit is
placed on the degree of large-scale surface structure on alpha Ori.

---------------------------------------------------------
Title: The outher atmospheres of cool stars. VII. High resolution,
absolute flux profiles of the MG II H and K lines in stars of spectral
types F8 to M5.
Authors: Stencel, R. E.; Mullan, D. J.; Linsky, J. L.; Basri, G. S.;
Worden, S. P.
1980ApJS...44..383S Altcode:
We present high-resolution lUE spectra of the emission cores of the
Mg II resonance doublet at 280 nm in a selection of 54 stars covering
a range of spectral type from F8 to MS and of luminosity class from
supergiant (Ia) to subgiant (IV). These spectra were obtained with the
LWR echelle system onboard the IUE satellite, and have been calibrated
in absolute flux units using OAO 2 photometry of Eta UMa as a standard,
plus the Barnes and Evans relations for stellar angular diameters. The
uncertainty in flux is probably of order 20%. We discuss the qualitative
line profile groupings, as determined by Basri and Linsky, and derive
chromospheric radiative losses in the h and k lines; we discuss
these loss rates as functions of effective temperature and luminosity
class. We make further comparisons of these rates with rates derived
for the Ca II H and K lines by Linsky and his colleagues. Chromospheric
velocity fields and indicators of circumstellar envelopes are discussed
in terms of profile asymmetries and other diagnostics. Line width
measures and velocity shifts of the central reversals are tabulated,
among other quantities, and several correlations noted. Finally, we
discuss the relation of the Wilson K index and stellar coronae to Mg
II emission, and note the occurrence of Fe II emission lines in the
middle range of the UV of late-type stars.

---------------------------------------------------------
Title: The Chromospheres of M Dwarf Stars
Authors: Giampapa, M. S.; Worden, S. P.; Linsky, J. L.
1980BAAS...12..807G Altcode:
No abstract at ADS

---------------------------------------------------------
Title: High Speed Photometry of Stepanian's Star
Authors: Worden, S. P.; Eason, E. L. E.; Africano, J.; Klimke, A.
1980BAAS...12..851W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Photometric Observations of Active Chromosphere Stars
Authors: Wilkerson, M. S.; Rogers, W.; Ruden, S.; Africano, J. L.;
Klimke, A.; Worden, S. P.
1980BAAS...12Q.807W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Status of Cloudcroft Solar Variability Program
Authors: Worden, S. P.; Eason, E.; Africano, J.; Klimke, A.; Radick,
R.; Wilkerson, M. S.
1980BAAS...12..897W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Speckle Interferometric Observations of Pallas
Authors: Hege, E. K.; Cocke, W. J.; Hubbard, E.; Gresham, M.;
Strittmatter, P. A.; Worden, S. P.; Radick, R.
1980BAAS...12R.509H Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Large Scale Solar Velocity Features
Authors: Kuhn, J. R.; Worden, S. P.
1980BAAS...12..473K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The diameter of chi Cygni by speckle interferometry.
Authors: Christou, J.; Worden, S. P.
1980AJ.....85..302C Altcode:
The technique of speckle interferometry is applied to Chi Cygni, a
Mira-type variable, giving a mean diameter of (23.08 plus or minus
4.08) x 10 to the -3rd arcsec. Two methods of data reduction were
applied giving good agreement with each other. The result tends to
support the conclusion of Labeyrie et al. (1977) that Mira stars have
radii R not greater than 18 solar radii as opposed to the previously
assumed value of R 320 solar radii.

---------------------------------------------------------
Title: Observations of magnetic fields on two late-type dwarf stars.
Authors: Robinson, R. D.; Worden, S. P.; Harvey, J. W.
1980ApJ...236L.155R Altcode:
The detection of magnetic fields on the G8 V star Xi Boo A and on
the K0 B star 70 Oph A is reported. A method has been developed
and applied which provides estimates of the total field strength
and fraction of the visible stellar surface covered by fields. The
essence of this method is to perform the Fourier deconvolution of a
nonmagnetically sensitive line profile from a magnetically sensitive
one. This method is insensitive to magnetic field geometry and does not
depend on polarization measurements. Results indicate fields of 2550 +
or 390 gauss covering 20-45% Xi Boo A, and that fields of 1880 + or -
350 gauss may cover 10% of 70 Oph A. Comparison observations of solar
active regions show fields of 1800 + or - 550 gauss covering 10% of
the solar active regions, in line with previous work. Tests of solar
quiet regions and sunspots also support the validity of the stellar
measurements.

---------------------------------------------------------
Title: Observational Astronomy at the Cloudcroft Observatory
Authors: Schneeberger, Timothy J.; Worden, S. P.
1980srca.conf...67S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Sources of noise in solar limb definitions
Authors: Keil, S. L.; Worden, S. P.
1980LNP...125..219K Altcode: 1980nnsp.work..219K
A test series of spectroheliograms has been used to evaluate
the hypothesis that the rotation and evolution of solar surface
structure can function as a source of noise in solar limb definition
measurements. The study confirms the hypothesis, and results demonstrate
the amount of variation in solar limb position which is attributable
to evolutionary changes in solar surface structure.

---------------------------------------------------------
Title: Cloudcroft Observatory Today
Authors: Schneeberger, Timothy J.; Worden, S. P.; Africano, J. L.;
Tyson, E.
1980S&T....59..109S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: High angular resolution astronomical techniques. Speckle
interferometry and related methods.
Authors: Worden, S. P.
1980SPIE..243...66W Altcode:
A review of speckle interferometry techniques and hardware for
recovering image information degraded by turbulence (which reduces
angular resolution to about 1 arcsec) in the earth's atmosphere is
presented. Speckle interferometry, which relies on post processing
of short exposure images, provides two orders of magnitude increase
in angular resolution for studying object sizes and binary star
orbits. Lynds et al. (1976) showed that images of bright stars were
directly obtainable from speckle photos. For more general image
reconstruction, the power spectrum used to determine angular sizes
must be supplemented with Fourier phases. Knox and Thompson (1974)
developed statistical techniques to get the phase from speckle photos
directly; however, the techniques are highly noise sensitive and limited
to bright objects like the sun. A method developed by Fienup (1978) was
applied to derive phases for faint astronomical targets. The method is
insensitive to noise and shows that actual diffraction-limited images
can be reconstructed for objects fainter than +15 magnitudes.

---------------------------------------------------------
Title: New Photometric Observations of EX Hydrae
Authors: Africano, J. L.; Quigley, R.; Schneeberger, T. J.; Worden,
S. P.
1979BAAS...11..649A Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Detection of Magnetic Fields on Late-type Stars
Authors: Robinson, R. D.; Boice, D.; Worden, S. P.
1979BAAS...11..648R Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Flare Activity on T Tauri Stars
Authors: Schneeberger, T. J.; Worden, S. P.; Kuhn, F. R.; Africano,
J. L.
1979BAAS...11..628S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: High Resolution Spectra of Stellar Flares
Authors: Worden, S. P.; Schneeberger, T. J.; Deluca, E.; Giampapa, M.
1979BAAS...11..628W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Ca II H and K Lines in dMe and non-dMe Stars
Authors: Giampapa, M. S.; Worden, S. P.; Schneeberger, T. J.; Cram,
L. E.
1979BAAS...11..625G Altcode:
No abstract at ADS

---------------------------------------------------------
Title: High-resolution line profiles of T Tau stars.
Authors: Schneeberger, T. J.; Worden, S. P.; Wilkerson, M. S.
1979ApJS...41..369S Altcode:
Thirty-three relative intensity hydrogen and sodium line profiles
obtained from spectra of 10 T Tauri stars are presented. These profiles
were derived from echelle spectrograms having a typical resolution of
0.20 A. The T Tauri stars observed span the range of emission-intensity
classes listed in Herbig and Rao (1972). Seventy percent of the H alpha
profiles show blue-displaced absorption components with velocities up to
250 km/sec. Na D emission features are observed in all the stars with
emission-intensity classes higher than 2. The Na D lines in T Tauri
show intensity changes on a time scale of months. The H alpha-line
equivalent width in T Tauri can change by 40% in 3 days.

---------------------------------------------------------
Title: Stellar model chromospheres. X. High-resolution, absolute
flux profiles of the Ca II H and K lines in stars of spectral types
F0 - M2.
Authors: Linsky, J. L.; Worden, S. P.; McClintock, W.; Robertson, R. M.
1979ApJS...41...47L Altcode:
We present 120 mÅ resolution spectra of the cores and wings of the Ca
II H and K lines in 43 stars covering a wide range of spectral type
and luminosity class. These spectra were obtained with the KPNO 4 m
echelle spectrograph and blue image tube, and are calibrated in absolute
surface flux units using Willstrop's narrow-band photometry and the
Barnes and Evans relations for stellar angular diameters. We estimate
an uncertainty of ±15% in our flux scales. We derive chromospheric
radiative loss rates in the H and K lines, and discuss trends in
these loss rates with effective temperature for dwarfs, giants, and
supergiants. We compare these loss rates with similar rates for the
Mg II h and k lines, and discuss the doublet line ratios for H and
K. The monochromatic surface fluxes for different features in the H
and K lines are presented. From the surface fluxes at K1
we derive the radiation temperature TR(K1). The
TR(K1)/Teff ratio is lower in giants
than in dwarfs, as predicted by partial redistribution calculations,
and this ratio appears to be an empirical age indicator among
dwarfs. Asymmetries in the K line profile provide evidence for a
solar-type supergranulation flow pattern in F5-K5 dwarfs and perhaps
also in G and early K supergiants. Measurements of line widths at
H1, K1, and K2 are presented, together
with FWHM data for the H and K lines. We find rough agreement between
the measured K1 widths and the gravity and chromospheric heating
rate dependences in the scaling law proposed by Ayres. Finally, we
present data on emission lines in the wings of H and K, and discuss
chromospheric radiative loss rates in the HE line compared with loss
rates in the H and K lines.

---------------------------------------------------------
Title: Speckle interferometery. I. The Steward Observatory.
Authors: Hubbard, G.; Hege, K.; Reed, M. A.; Strittmatter, P. A.;
Woolf, N. J.; Worden, S. P.
1979AJ.....84.1437H Altcode:
The Steward Observatory speckle camera is described. The optical system
images light onto a four stage image tube which is then lens-coupled to
either a photographic camera or to a CID camera. The device has been
used in its photographic mode to study the extent of the isoplanatic
patch at the 2.3 m telescope. With 20 ms exposures, the correlation
between the speckle patterns of close binary systems has essentially
disappeared for separations exceeding 6 arcsec.

---------------------------------------------------------
Title: The lifetimes of sunspot moats.
Authors: Pardon, L.; Worden, S. P.; Schneeberger, T. J.
1979SoPh...63..247P Altcode:
Daily full disk magnetograms observed with the Kitt Peak 40 channel
magnetograph have been examined for the rise time, decay time and
lifetime of sunspot moats. Eighteen well defined moats result in rise
and decay times of 0.5d ± 1d, with a lifetime at maximum development
of 6d ± 3d. The moat appears approximately 3 days after the spot is
observed in our data.

---------------------------------------------------------
Title: The night sky conditions at the Sacramento Peak
Observatory. I. Sky brightness.
Authors: Schneeberger, T. J.; Worden, S. P.; Beckers, J. M.
1979PASP...91..530S Altcode:
The night sky brightness at Sacramento Peak Observatory has been
monitored over a period of nine months. The average zenith sky is 21.9
± 0.1 mυ arc sec-2. The night sky brightness
shows fluctuations of up to 25% during this period. The long record
of daytime sky-brightness observations shows a strong seasonal effect
with brightest skies occurring in the early summer months. This seasonal
effect is marginally present in the night sky brightness results. Light
pollution from the closest urban areas is also detailed.

---------------------------------------------------------
Title: Chromospheric emission lines in the red spectrum of AD
Leonis. II. Physical conditions in flares.
Authors: Schneeberger, T. J.; Linsky, J. L.; McClintock, W.; Worden,
S. P.
1979ApJ...231..148S Altcode:
Simultaneous photometry and time-resolved spectra of the dMe flare star
AD Leo has been used to deduce flare temperatures, electron densities,
and dimensions. Photometric results for two qualitatively different
flares yield estimates of the differences in physical properties
between these flares. Flares on AD Leo are hotter and denser than their
solar counterparts, and spike-like flares occupy smaller volumes than
longer-lived flares. An upper limit to the flare X-ray luminosity is
set atL &lt;4 x l028ergss-1. Subject headings: stars: chromospheres -
stars: emission-line - stars: flare - stars: individual

---------------------------------------------------------
Title: The effect of chromospheric activity on metallicity
measurements.
Authors: Giampapa, M. S.; Gilliam, L. B.; Worden, S. P.
1979ApJ...229.1143G Altcode:
The intermediate band uvby-beta photometric system is used to observe
solar active (plage) regions and quiescent regions in an effort
to determine the effect of chromospheric activity on photometric
metallicity measurements. It is found that the active regions appear
metal deficient with respect to the quiet sun by approximately 35%.

---------------------------------------------------------
Title: Short Time Scale Brightness Fluctuations in BP Tauri
Authors: Schneeberger, T. J.; Worden, S. P.; Africano, J. L.
1979IBVS.1582....1S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Stellar model chromospheres. IX. Chromospheric activity in
dwarf stars.
Authors: Kelch, W. L.; Linsky, J. L.; Worden, S. P.
1979ApJ...229..700K Altcode:
High-resolution Ca II K line profiles are used to model the upper
photospheres and lower chromospheres of eight main-sequence stars
ranging in spectral type from F0 to M0 and exhibiting different degrees
of chromospheric activity. The model chromospheres are studied as a
function of spectral type and activity for stars of similar spectral
type in order to obtain evidence of enhanced nonradiative heating in the
upper-photospheric models and in the ratio of minimum temperature at the
base of the chromosphere to effective temperature, a correlation between
activity and temperature in the lower chromospheres, and a correlation
of the width at the base of the K-line emission core and at the K2
features with activity. Chromospheric radiative losses are estimated
for the modelled stars and other previously analyzed main-sequence
stars. The results obtained strengthen the argument that dMe flare stars
exhibit fundamentally solar-type activity but on an increased scale.

---------------------------------------------------------
Title: Simultaneous X-ray, UV, Optical, and Radio Observations of
the Flare Star Proxima Centauri
Authors: Haisch, B. M.; Linsky, J. L.; Slee, O. B.; Worden, S. P.
1979BAAS...11..471H Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Short Time Scale Brightness Fluctuations in T Tauri Stars.
Authors: Schneeberger, T. J.; Worden, S. P.; Africano, J. L.
1979BAAS...11..439S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Evidence of long-period velocity fluctuations.
Authors: Kuhn, J. R.; Worden, S. P.
1979ApJ...228L.119K Altcode:
Evidence of a solar fluctuation with a period of 17 days is observed
in spectroscopic differential-rotation data by using a technique
developed to look at long time sequences of unevenly spaced data. Both
spectroscopic observations and sunspot drift-velocity measurements
indicate a possible periodicity between 184 and 364 days. The sunspot
data marginally show fluctuations with periods which are multiples of
4.2 days.

---------------------------------------------------------
Title: Period Variation of UX Ursae Majoris in 1979
Authors: Quigley, R.; Africano, J. L.; Schneeberger, T. J.; Worden,
S. P.
1979BAAS...11..445Q Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Sources of Noise in Solar Limb Definitions.
Authors: Worden, S. P.; Keil, S. L.
1979BAAS...11..399W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Photometric Eclipse Timings of RW TRIANGULI
Authors: Africano, J. L.; Quigley, R.; Scheeberger, T. J.; Worden,
S. P.
1979BAAS...11..433A Altcode:
No abstract at ADS

---------------------------------------------------------
Title: AH Cancri: a contact binary in M67.
Authors: Whelan, J. A. J.; Worden, S. P.; Rucinski, S. M.; Romanishin,
W.
1979MNRAS.186..729W Altcode:
The W UMa-type contact binary system AH Cnc, which is a member of
the old galactic cluster M67, has been studied spectroscopically and
photometrically. Estimates of masses, radii, effective temperature and
luminosity of AH Cnc have been derived from these data and from cluster
membership considerations. The results suggest that AH Cnc is a typical
evolved W-type W UMa contact system, although whether the system has
evolved as a contact system or has recently become so, could not be
determined. The properties of AH Cnc are similar to those of TX Cnc
in Praesepe. Information provided by the existence of a gap in the
Hertzsprung-Russell diagram for M67 has been coupled with the AH Cnc
results to provide further estimates of the chemical composition of M67.

---------------------------------------------------------
Title: Nucleosynthesis of 7Li in flares on UV Ceti stars.
Authors: Karpen, J. T.; Worden, S. P.
1979A&A....71...92K Altcode:
The possible production of Li-7 by nuclear reactions in UV Ceti flares
has been considered. By utilizing solar observations and theory, a
relationship is derived between flare energy and production rates for
Li-7; approximately 100 erg of total flare energy is found to denote
the formation of a Li-7 atom. Based on this value and best estimates
of UV Ceti-type flare rates, it is concluded that less than 10% of
the Li-7 observed in the intestellar medium may have been produced
by this mechanism. Formation of significant amounts of interstellar
deuterium by this method is ruled out.

---------------------------------------------------------
Title: A Contact Binary in M67
Authors: Whelan, J. A. J.; Worden, S. P.; Rucinski, S. M.; Romanishin,
W.
1979NZJS...22..449W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Angular diameter of the asteroids Vesta and Pallas determined
from speckle observations.
Authors: Worden, S. P.; Stein, M. K.
1979AJ.....84..140W Altcode:
The technique of speckle interferometric measurement of asteroids is
applied to Vesta and Pallas, yielding diameters of 550 i 23 and 673+55
km, respectively. The improved Vesta speckle diameter is in excellent
agreement with other measurements for Vesta. However, the derived
Pallas diameter is slightly larger than other measurements. This
is perhaps attributable to systematic errors arising as an object's
angular diameter nears the seeing disk size. It is also pointed out
that it is necessary to carefully normalize and center speckle frames
before applying the autocorrelation ,cross-correlation subtraction
method developed by Worden et al. [Icarus 32, 450 (1977)].

---------------------------------------------------------
Title: Interferometric determinations of asteroid diameters.
Authors: Worden, S. P.
1979aste.book..119W Altcode:
New interferometric techniques are discussed with reference
to asteroid studies. Speckle interferometry makes it possible
to recover some information down to large telescope diffraction
limits. A multiple-aperture amplitude interfermeter system allows
the full telescope aperture to be covered simultaneously and all
Fourier components sampled simultaneously. The new techniques make it
possible to directly determine diameters of asteroids from earth-based
observations. Results for some solar system objects are given. New
possibilities include image reconstruction for asteroids and the
detection of close asteroid pairs.

---------------------------------------------------------
Title: The Cloudcroft Observatory 48 inch telescope.
Authors: Africano, J. L.; Schneeberger, T. J.; Worden, S. P.
1979BAAS...11..392A Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Digital speckle interferometry to measure the angular diameters
of faint objects
Authors: Hubbard, G.; Reed, M.; Strittmatter, P.; Hege, K.; Worden,
S. P.
1979hars.proc...28H Altcode: 1979IAUCo..50...28H
A digital speckle camera for use on a 90-inch telescope has been
developed. This camera uses a CID detector to provide photon locations
in an image, or an analog image for brighter objects. This system has
been used to observe Saturn's satellites Rhea and Iapetus. A correlation
speckle technique is used to determine angular diameters of 1487 +
or - 40 km for Rhea and 1200 + or - 132 km for Iapetus.

---------------------------------------------------------
Title: MG II and FE II Resonance Line Studies in Extremely Luminous
F Stars
Authors: Worden, Simon P.
1979iue..prop..266W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Chromospheric emission lines in the red spectrum of AD
Leonis. I. The nonflare spectrum.
Authors: Giampapa, M. S.; Linsky, J. L.; Schneeberger, T. J.; Worden,
S. P.
1978ApJ...226..144G Altcode:
High-resolution red (5300-7300 A) spectra of the flare star AD Leonis
were obtained with the Kitt Peak 4 m echelle spectrograph system
at a spectral resolution of 0.22 A at Ha. A series of time-trailed
plates with 5 hours integration in total were averaged together
to obtain a representation of the star's nonflaring spectrum with
high signal-to-noise ratio. The He i A5876 triplet line and A6678
singlet line appear in emission with measured equivalent widths of
0.312 + 0.016 A and 0.058 + 0.029 A, respectively. The corresponding
triplet-to-singlet line flux ratio is 3.7, close to the ratio of the
level statistical weights. We argue that the He i lines are not produced
by recombination and cascade following photoionization by A &lt; 504
A coronal photons, but are instead collisionally excited. We suggest
that these lines are formed in a geometrically thin chromospheric layer
at 20,000-50,000 K with a column density of nel 6 x 1018 . The sodium
D emission lines (A5890, AS 896) are found to be stellar in origin,
with measured FWHM of 0.7 A for both lines, and the Ha line has a
FWHM of 1.4 A. No other chromospheric emission lines were found in
this spectral region. Subject headings: stars: chromospheres - stars:
emission-line - stars: flare - stars: individual

---------------------------------------------------------
Title: Image Reconstruction Using Speckle Interferometry
Authors: Worden, S. P.
1978BAAS...10..630W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: On Egregious Theories-The Tunguska Event
Authors: Wilkerson, M. S.; Worden, S. P.
1978QJRAS..19..282W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Evidence of Long Period Solar Velocity Fluctuations
Authors: Kuhn, J. R.; Worden, S. P.
1978BAAS...10..639K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A study of the contact binary system ER Cephei.
Authors: Worden, S. P.; Coleman, G. D.; Rucinski, S. M.; Whelan,
J. A. J.
1978MNRAS.184...33W Altcode:
Summary. Photoelectric V and B light curves of ER Cephei, a 1 6-mag
W Ursae Majoris-type binary system in NGC 188, are described. The
available data are not sufficient definitely to determine whether the
light curve of the system is of A type or W type, although this analysis
suggests the latter. Light-curve synthesis solutions are calculated
for both cases, together with their uncertainties. The results show
that ER Cep is similar to field contact binaries, is in marginal
contact, has a well-determined inclination angle, i = 79 j 30, and has
a poorly determined mass ratio, q = 0.55 +0.20. A brief discussion is
given of system parameters for ER Cep derived from cluster membership
considerations. The need for spectroscopic data and the importance of
ER Cep for cluster Hertzsprung-Russell diagram gap theory is stressed.

---------------------------------------------------------
Title: Speckle interferometry.
Authors: Worden, S.
1978NewSc..78..238W Altcode:
It is noted that atmospheric twinkling (or 'seeing') limits the
resolution obtainable from ground-based telescopes. The limit of
angular resolution is inversely proportional to the diameter of the
main light collector. Turbulence in the earth's atmosphere degrades this
angular resolution. In order to rectify this problem, multiple-aperture
interferometers, consisting of a large number of images superimposed
on each other, have been used. These 'speckled' images may be analyzed
with Fourier mathematics and Fourier processing. The methods have
been used for studying binary stars and for determining the sizes
of asteroids and the sun. A technique has also been developed for
reconstructing actual images of Betelgeuse, the red star in the shoulder
of the Orion constellation. It is based on computer processing data
on individual speckles in a series of images. In the future speckle
size determinations will be extended to quasars and exploding galactic
nuclei.

---------------------------------------------------------
Title: Speckle Interferometry at Steward Observatory.
Authors: Hubbard, E.; Strittmatter, P. A.; Woolf, N. J.; Hege, K.;
Worden, S. P.
1978BAAS...10..459H Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Effects of Stellar Chromospheric Activity on Metallicity
Measurements.
Authors: Giampapa, M. S.; Worden, S. P.
1978BAAS...10..458G Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Equivalence principle tests in Earth orbit.
Authors: Worden, P. W., Jr.
1978AcAau...5...27W Altcode:
An analysis of experiments which test the uniqueness of the ratio of
inertial and passive gravitational mass has been made. The analysis
shows that an improvement in sensitivity of at least six orders
of magnitude is possible in Earth orbit. The optimum experiment
compares the rate of fall of two independent test bodies in a cryogenic
environment aboard a drag-free satellite; this "free fall" experiment
is very much less sensitive to gravity gradient than is a torsion
balance. The dominant noise sources for such an experiment are expected
to be gravity gradients, tracking errors, and gas pressure effects;
thermal noise is not a limiting factor. A laboratory version of the
experiment is under test; preliminary results are described.

---------------------------------------------------------
Title: The helium triplet-to-singlet ratio in T Tauri stars.
Authors: Schneeberger, T. J.; Linsky, J. L.; Worden, S. P.
1978A&A....62..447S Altcode:
Summary. The He ilines at 5876 and 6678 are used to determine the
triplet-to-singlet ratio for T Tauri stars DF Tau and BP Tau. The
ratio is approximately 3. Line profiles and absolute intensities are
presented. Key words: T Tauri stars helium lines

---------------------------------------------------------
Title: Speckle Interferometry
Authors: Worden, S. P.
1978NewSc...4..238W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A Method for Processing Stellar Speckle Interferometry Data
Authors: Welter, G. L.; Worden, S. P.
1978JOSA...68.1271W Altcode: 1978OSAJ...68.1271W
No abstract at ADS

---------------------------------------------------------
Title: The Angular Diameter of Vesta from Speckle Interferometry
Authors: Worden, S. P.; Stein, M. K.; Schmidt, G. D.; Angel, J. R. P.
1977Icar...32..450W Altcode:
It is shown that the autocorrelation function of a telescope
diffraction-limited image is closely approximated by a subtraction
of the mean cross correlation of pairs of speckle photographs from
the mean autocorrelation of the same set of data. This fact is used
to derive the angular diameter of the asteroid Vesta from a series of
speckle interferometry data. The resultant apparent angular diameter of
0″.40 ± 0″.04 corresponds to an absolute diameter of 513 ± 51 km.

---------------------------------------------------------
Title: Large-scale winds driven by flare-star mass loss.
Authors: Coleman, G. D.; Worden, S. P.
1977ApJ...218..792C Altcode:
The effect of injecting substantial quantities of high-temperature
material into the interstellar medium from flare-star activity is
examined. Using models like those developed by Mathews and Baker for
calculating supernovae-driven elliptical galaxy winds, we consider the
effects of flare-star mass loss in elliptical galaxies and globular
clusters. It is found that, even in the absence of supernovae,
and with a substantially smaller flare-star mass input than may be
plausibly expected, steady outflowing winds will develop in these
objects. Such winds may explain the observed absence of substantial
quantities of interstellar material in globular clusters and elliptical
galaxies. Assuming the presence of elliptical galaxy winds in clusters
of galaxies, we consider the effects of such winds on intergalactic
medium dynamics. We find that a hot intergalactic medium is to be
expected and that instabilities resulting in collapse in the center
of clusters of galaxies may occur.

---------------------------------------------------------
Title: Spectroscopic orbit of CC Comae.
Authors: Rucinski, S. M.; Whelan, J. A. J.; Worden, S. P.
1977PASP...89..684R Altcode:
Radial velocity measurements of CC Corn, the shortest period W UMa-type
system, are resented. The results are combined with photometric results
to provide an estimate of the absolute elements. The system has total
luminosity 0.29 :1: 0.03 Lu and masses of 0.69 :1: 0.06 , and 0.36
:1: 0.03 @. Formal errors are quoted here, and the possibility of
much larger systematic errors is discussed in the text. The value of
the mass ratio derived spectroscopically (0.52 :1: 0.03) conflrrns
the value derived from photometry. The distance to CC Corn (83 :1:
4 pc) is discussed with reference to membership of the Coma cluster
(Mel 111). The importance of CC Corn for theoretical models of contact
binary systems is stressed. Key words: stars: individual-spectroscopic
elements-contact binaries

---------------------------------------------------------
Title: Chromospheric Emission Lines in the Quiescent Spectrum of
the Flare Star AD Leo
Authors: Giampapa, M. S.; Linsky, J. L.; Schneeberger, T. J.; Worden,
S. P.
1977BAAS....9..593G Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Modeling of Chromospheric Activity in F-M Dwarf Stars and
the Sun.
Authors: Kelch, W. L.; Linsky, J. L.; Worden, S. P.
1977BAAS....9..651K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Image restoration techniques applied to QSO images.
Authors: Wehinger, P. A.; Worden, S. P.; Wyckoff, S.
1977BAAS....9..608W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Image Restoration Techniques Applied to QSO Images
Authors: Wehinger, P. A.; Worden, S. P.; Wyckoff, S.
1977BAAS....9Q.608W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Simultaneous Photometry and Time Resolved Spectra of Flare
Star AD Leo
Authors: Schneeberger, T. J.; Worden, S. P.; Linsky, J. L.;
McClintock, W.
1977BAAS....9Q.593S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Further speckle interferometric studies of alpha Orionis.
Authors: Wilkerson, M. S.; Worden, S. P.
1977AJ.....82..642W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: INVITED PAPER - Solar and Stellar Speckle Interferometry.
Authors: Worden, S. P.
1977BAAS....9R.374W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: On the Origin of Oscillations in the Solar Limb Position.
Authors: Worden, S. P.; Simon, G. W.
1977BAAS....9..358W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Astronomical image reconstruction
Authors: Worden, S. P.
1977VA.....20..301W Altcode:
Atmospheric turbulence limits angular resolution of earth-based
telescopes to about one arc-second. A technique, speckle interferometry,
has been developed which uses very short exposure photographs to obtain
information approaching the limit of telescope angular resolution
permitted by the Rayleigh limit. Procedures for reconstructing images
free from atmospheric smearing by means of speckle interferometry and
related methods are discussed. Different approaches include: direct
Fourier deconvolution, considering speckles as images, generalized image
reconstruction, and active systems which require no post-detection
processing (for example, a system using a mirror with a deformable
surface, known as the 'rubber mirror'). Photographic speckle apparatus
is described and the limitations of the procedure are examined.

---------------------------------------------------------
Title: Direct observations of the heterogeneity of supergiant disks.
Authors: Harvey, J. W.; Lynds, C. R.; Worden, S. P.
1977oehs.conf..405H Altcode:
No abstract at ADS

---------------------------------------------------------
Title: On the origin of the 2h40m solar
oscillations.
Authors: Worden, S. P.; Simon, G. W.
1976ApJ...210L.163W Altcode:
The existence of a 2-hr 40-min global solar velocity oscillation has
recently been reported. The present letter examines the possibility that
this phenomenon represents the rotation of large-scale solar velocity
cells (supergranulation) through the field of view of the instrument
used to detect the oscillations. On the basis of high-resolution
full-disk velocity data, it is concluded that this mechanism can
produce apparent oscillations with periods near 2 hr 40 min.

---------------------------------------------------------
Title: Reconstructed images of Alpha Orionis using stellar speckle
interferometry.
Authors: Worden, S. P.; Lynds, C. R.; Harvey, J. W.
1976JOSA...66.1243W Altcode: 1976OSAJ...66.1243W
A recently developed technique to recover nearly diffraction-limited
images of supergiant stars such as Alpha Orionis (Betelgeuse)
from speckle interferometry data is discussed. This method relies
on the digital identification and coaddition of the brightest
individual speckles within a large number of short-exposure speckle
photographs. The resulting average speckle may be thought of as the
convolution of a point source speckle profile with the actual object
intensity pattern. By making use of this point angular diameters and
limb darkening coefficients are derived in addition to finding evidence
of possible surface structure on the star.

---------------------------------------------------------
Title: Looking at the surfaces of other stars
Authors: Worden, Simon P.
1976PhTea..14..514W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: High Spectral Resolution K Line Observations of Active
Chromosphere Stars.
Authors: Linsky, J. L.; Worden, S. P.
1976BAAS....8..519L Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Digital image reconstruction applied to Alpha Orionis.
Authors: Lynds, C. R.; Worden, S. P.; Harvey, J. W.
1976ApJ...207..174L Altcode:
Short-exposure photographs at high magnification have been obtained
for the M2 Ia-b supergiant alpha Ori with a 4-m telescope. Optical
passbands were chosen which isolate a temperature-sensitive TiO band
and, for comparison, a nearby section of continuum. The photographs
have been digitized and subjected to a deconvolution procedure which
gives reconstructed images of the surface of the star. The images
indicate a small difference in the angular dimensions of the star as
observed through the two different filters, and there is some evidence
supporting the presence of surface structure. The particular procedure
employed in the reconstruction of the images has only a limited range
of validity, but application of the procedure to photographs of the
unresolved star gamma Ori not only served the necessary function of
determining the final point-spread function but also yielded images
showing a diffraction pattern apparently related to the theoretical
Airy pattern of the telescope.

---------------------------------------------------------
Title: The emission lines in the vicinity of hydrogen-alpha in dMe
flare star spectra.
Authors: Worden, S. P.; Peterson, B. M.
1976ApJ...206L.145W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Mass Loss from Dwarf M Stars Through Stellar Flaring
Authors: Coleman, Gary D.; Worden, Simon P.
1976ApJ...205..475C Altcode:
It is shown that mass loss from dwarf M stars arising from flaring
and stellar winds may lead to a significant mass and energy input into
the interstellar medium. It is further demonstrated that the stellar
flares on these stars may be producing through nuclear reactions a
large fraction of the observed interstellar deuterium. The same mass
loss would also give rise to substantial galactic winds in galaxies
with small ambient interstellar gas components. These results show
that stellar flaring can account for many effects previously ascribed
to supernovae. Subject headings: interstellar: matter - stars: flare -
stars: late-type - stars: mass loss

---------------------------------------------------------
Title: On the Origin of 2h 40m Global Solar
Oscillations
Authors: Worden, S. P.
1976BAAS....8..310W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Digital analysis of speckle photographs: the angular diameter
of Arcturus.
Authors: Worden, S. P.
1976PASP...88...69W Altcode:
Digital reduction of speckle interferometry data for the K2 III
giant a Boo (Arcturus) has been done. Angular diameters of o':
019 i 0': 006 were obtained at 4200 A for a uniformly illuminated
disk, and 0,027 i 0,010 for a highly limb-darkened disk. Arcturus
is underresolved using the Kitt Peak National Observatory 4-meter
telescope. The digital-reduction scheme described here proved ideal
for studying such underresolved objects. A discussion of limitations
of this technique is also provided. Key words: speckle interferometry -
atmospheric seeing - resolution

---------------------------------------------------------
Title: A study of supergranulation using a diode array magnetograph.
Authors: Worden, S. P.; Simon, G. W.
1976SoPh...46...73W Altcode:
The evolution of the velocity and magnetic fields associated with
supergranulation has been investigated using the Sacramento Peak
Observatory Diode Array Magnetograph. The observations consist of time
sequences of simultaneous velocity, magnetic field, and chromospheric
network measurements. From these data it appears that the supergranular
velocity cells may have lifetimes in excess of the accepted value
of 24 hours. Magnetic field motions associated with supergranulation
were infrequent and seem to be accompanied by changes in the velocity
field. More prevalent were the slow dissipation and diffusion of
stationary flux points. Vertical velocity fields of 200 m s−1 appear
to be confined to downflows in magnetic field regions at supergranular
boundaries. These downflows are only observed using certain absorption
lines. Corresponding upflows in the center of supergranules of less
than 50 m s−1 may be present but cannot be confirmed.

---------------------------------------------------------
Title: Velocities Observed in Super-Granules
Authors: Worden, S. P.; Simon, G. W.
1976IAUS...71..121W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Cryogenic test of the equivalence principle.
Authors: Worden, P. W., Jr.
1976PhDT.......167W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Astronomical image reconstruction
Authors: Worden, S. P.
1975aifo.reptW....W Altcode:
Recently proposed methods for reconstructing large telescope
astronomical images free from atmospheric perturbation are reviewed
and discussed.

---------------------------------------------------------
Title: Infrared Observations of Supergranule Temperature Structure
Authors: Worden, S. P.
1975SoPh...45..521W Altcode:
One and two-dimensional observations were made at 1.64 μ,
the deepest observable level in the solar atmosphere; at 1.72 μ,
representing the chromosphere; and at 1.17 μ, representing the visible
photosphere. Structures distributed on a supergranular size scale (30000
km) are apparently present at all levels. These structures in the deep
photospheric level (1.64 μ) seem to be a 50K-500K temperature decrease
over surrounding photosphere confined to the magnetic field elements
with horizontal scales less than 4000 km at supergranular boundaries,
rather than a general temperature structure over the entire supergranule
cell appropriate to convective energy transport.

---------------------------------------------------------
Title: The limitations of astronomical image reconstruction
Authors: Worden, S. P.
1975Obs....95..291W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The angular diameter of Alpha Herculis A.
Authors: Worden, S. P.
1975ApJ...201L..69W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Flare Stars and Galactic Winds
Authors: Coleman, G. D.; Worden, S. P.
1975BAAS....7R.528C Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Flare stars and galactic winds.
Authors: Coleman, G. D.; Worden, S. P.
1975BAAS....7..538C Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Heights of Formation of Non-Magnetic Solar Lines Suitable
for Velocity Studies
Authors: Altrock, R. C.; November, L. J.; Simon, G. W.; Milkey, R. W.;
Worden, S. P.
1975SoPh...43...33A Altcode:
Heights of formation of lines that do not exhibit Zeeman splitting
are calculated using an LTE, partial non-LTE, and full non-LTE
approach. Non-magnetic (g=0) lines are valuable for velocity
investigations in quiet-Sun magnetic field regions, and a knowledge
of their formation heights is useful for obtaining three dimensional
velocity profiles in these regions.

---------------------------------------------------------
Title: The Character of 300-Second Oscillators.
Authors: November, L. J.; Simon, G. W.; Worden, S. P.
1975BAAS....7..407N Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Mass Loss from Stellar Flares.
Authors: Worden, S. P.; Coleman, G. D.
1975BAAS....7..398W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Composition and Composition Gradients in Disk Galaxies, I
Authors: Jensen, E. B.; Strom, S. E.; Worden, S. P.
1975BAAS....7..396J Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Solar supergranulation
Authors: Worden, Simon Peter
1975PhDT.......176W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Solar Supergranulation.
Authors: Worden, S. P.
1975PhDT.........2W Altcode:
A convective process originating some 10,000 km below the solar surface
was studied. Several observations designed to study the process
are examined. An alternate approach taken in understanding stellar
convection was the study of the dMe stars. A discussion of observational
results within the framework of solar and stellar convection
zone-magnetic interactions is provided. Simultaneous velocity, magnetic
field, and chromospheric emission network data were used to study the
lifetimes, the vertical velocity flow, and the transport of magnetic
fields associated with supergranulation. Horizontal magnetic field
motions take two forms: (1) an apparent slow breakup of existing flux
points; and (2) a rapid motion of flux following the emergence of new
magnetic field. The latter may be associated with the formation of a
new supergranule. Results are consistent with a generalized stellar
model in which strong magnetic fields are shown to be generated deep
within the star.

---------------------------------------------------------
Title: A Conjecture Regarding the dMe Stars
Authors: Worden, S. P.
1974PASP...86..595W Altcode:
The dMe stars are late-type main-sequence objects which exhibit
characteristics that can be explained as the result of solar-type
surface magnetic activity. The battery mechanism of Biermann (1950)
is used to explain the origin of the magnetic fields responsible for
the surface activity. Magnetic fields 10-100 times the strength of
solar magnetic fields can be produced in this manner. Such strong
fields are consistent with the observed dMe properties and should be
directly detectable.

---------------------------------------------------------
Title: Narrow-band photoelectric photometry of three dMe stars.
Authors: Jensen, E. B.; Worden, S. P.; Grasdalen, G. L.
1974PASP...86..601J Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Digital Image Reconstruction Applied to Betelgeuse.
Authors: Lynds, C. R.; Worden, S. P.; Harvey, J. W.
1974BAAS....6Q.459L Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A digital analysis of the polarization within the Serpens
nebula.
Authors: Worden, S. P.; Grasdalen, G. L.
1974A&A....34...37W Altcode:
Summary. Photographic linear polarization data was digitally analyzed
to determine the illuminating source for the Serpens Nebula (oc1950 =
18h27m24s5, a1950 = +0101 2'40"). The results were two-dimensionally
Fourier filtered to reduce noise. Some improvement in the data was
produced in this manner. The result of this procedure indicates that
the Serpens Nebula is a reflection nebula illuminated by an imbedded
star and not by a nearby infrared source as suggested by Strom et aL
(1974b). This illuminating star is probably a young zero age main
sequence star of spectral Type B 5-A 5. Key words: polarization-
reflection nebula digital analysis

---------------------------------------------------------
Title: W Ursae Majoris: mass-ratio discrepancy, third body and age.
Authors: Whelan, J.; Mochnacki, S. W.; Worden, S. P.
1974MNRAS.168...31W Altcode:
The discrepancy between the spectroscopically and photometrically
determined mass-ratios of W Ursae Majoris, and the observed
quasi-sinusoidal period variations may be understood if there is a
third body in the system which contributes about 4 per cent of the
light at maximum. The third body has a mass of about Mo and could be a
Hayashi star. The time scale for its contraction to the main-sequence
(5 x io8 yr) is of the same order as an estimate of the age of W Ursae
Majons (i- x io yr) deduced from the time since coincidence of W Ursae
Majoris and its proper motion companion BD + 55 1351. The inferred
age of W Ursae Majoris may be significant for contact binary evolution
theory. Several observational tests of the third-body hypothesis are
proposed. The possibility that the period changes are caused by mass
exchange, mass loss or apsidal motion cannot be ruled out and these
mechanisms are compared with the third-body hypothesis.

---------------------------------------------------------
Title: The effects of the 35-day X-ray cycle on the light curve of
HZ Herculis.
Authors: Grandi, S. A.; Hintzen, P. M. N. O.; Jensen, E. B.; Rydgren,
A. E.; Scott, J. S.; Stickney, P. M.; Whelan, J. A. J.; Worden, S. P.
1974ApJ...190..365G Altcode:
We report extensive photoelectric UB V photometry of the variable
star HZ Her, originally undertaken to discover possible correlations
between variations in its 1.7-day light curve and the 35-day cycle
of the X-ray source Her X-1. Correlations recently reported by other
groups are confirmed. These, as well as other features observed, are
provisionally analyzed using a model consisting of a primary star
filling its Roche lobe and being illuminated by X-rays. The X-rays
are emitted in a beam fixed in a rotating, precessing, neutron-star
secondary. Additional light is being contributed by material being
transferred from the primary to the secondary. Subject headings:
binaries - stars, individual - X-ray sources

---------------------------------------------------------
Title: A Digital Analysis of the Color Structure Within Messier 51
Authors: Worden, Simon P.
1974PASP...86...92W Altcode:
Blue and visual photographic plates of Messier 51 have been digitally
analyzed to give computer produced (B- V) maps of M51. The technique
used to accomplish this is described and this material is compared with
the preliminary Westerbork 21-cm neutral hydrogen data. The indication
of a ring of blue stars in the nucleus of M 51 is reported. Key words:
Messier 51 - (B- V) maps - 21-cm contours

---------------------------------------------------------
Title: The gyroscope experiment. - III: Tests of the equivalence of
gravitational and inertial mass based on cryogenic techniques
Authors: Worden, P. W., Jr.; Everitt, C. W. F.
1974exgr.conf..381W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The implications of the W Ursae Majoris type contact binary
in M67.
Authors: Worden, S. P.; Whelan, J.
1973PASP...85..540W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Photoelectric UBV Photometry of HZ Herculis.
Authors: Grandi, S. A.; Hintzen, P.; Jensen, E. B.; Rydgren, E.;
Scott, J. S.; Stickney, P. M.; Whelan, J. A. J.; Worden, S. P.
1973BAAS....5Q.440G Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Optical Pulsations of HZ Herculis
Authors: Cocke, W. J.; Hintzen, P.; Scott, J. S.; Worden, S. P.
1973NPhS..244Q.137C Altcode: 1973Natur.244Q.137C
ON April 15.3 (UT), we attempted to detect optical variations in HZ
Herculis corresponding to its 1.2 s X-ray pulsation period. No such
variations were observed to a limiting magnitude of 23.5 (modulation
0.01%).

---------------------------------------------------------
Title: TX CANCRI : the golden wonder.
Authors: Whelan, J. A. J.; Worden, S. P.; Mochnacki, S. W.
1973ApJ...183..133W Altcode:
Spectroscopic, photometric, and polarimetric observations of TX
Cancri, a W UMa-type binary system in Praesepe, are reported. The
parameters (masses, radii, luminosities) of the components of the
system are determined. If the system is evolved, then it must have lost
a substantial amount of mass to reach its present state. We argue that
TX Cnc is unevolved, and an age-zero contact-binary model for the system
is constructed. Problems in the interpretation of the parameters of the
system and the age-zero model are discussed. Subject headings: eclipsing
binaries - open clusters - stars, individual - W Ursae Majoris stars

---------------------------------------------------------
Title: The He+ λ 4686 line in the low chromosphere
Authors: Worden, S. P.; Beckers, J. M.; Hirayama, T.
1973SoPh...28...27W Altcode:
We report an unsuccessful search for the He+ λ 4686 line
in the low chromosphere. However, at the location of this line we
detect a number of other chromospheric emission lines. This leads
us to the conclusion that the He+ λ 4686 identification
made in the past, as well as other identifications, are probably in
error. Additionally the region of the neutral helium λ4713 line is
also studied.

---------------------------------------------------------
Title: W Ursae Majoris: the parameters of a contact binary.
Authors: Worden, S. P.; Whelan, J.
1973MNRAS.163..391W Altcode:
Spectroscopic radial velocity observations of W Ursae Majoris, the
prototype contact binary, are reported. The parameters (masses, radii,
luminosities) of the system have been determined and are given in Table
V. There is a real discrepancy between the spectroscopically determined
mass-ratio of W Ursae Majoris and the photometrically determined one. BD
+55 1351 and W Ursae Majoris share the same space motion which provides
an estimate of the distance to the system. A theoretical main-sequence
contact binary model is constructed which reproduces the observations.

---------------------------------------------------------
Title: The Mass-Ratio of W UMa.
Authors: Worden, S. P.; Whelan, J.
1973BAAS....5R..42W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: HZ Herculis.
Authors: Cocke, W. J.; Hintzen, P.; Scott, J. S.; Worden, S. P.
1973IAUC.2543R...1C Altcode:
No abstract at ADS

---------------------------------------------------------
Title: TX Cancri.
Authors: Whelan, J.; Worden, S. P.; Mochnacki, S. W.
1972BAAS....4Q.330W Altcode:
No abstract at ADS

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Title: Note on the Energy Scale of the Michigan OSO III Ion Chamber
Authors: Teske, Richard G.; Hodge, Philip E.; Worden, Simon P.
1972SoPh...22..235T Altcode:
The energy scale of the Michigan OSO III soft X-ray ion chamber has been
assessed by using realistic theoretical X-ray spectra. Multiplicative
factors by which the data may be corrected are proposed. The factors
are only slightly temperature-dependent. A test of the proposed energy
scale indicates it is still somewhat uncertain.

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Title: Re-evaluation of the Energy Scale of the Michigan OSO III
Ion Chamber Soft X-Ray Photometer.
Authors: Teske, R. G.; Hodge, P. W.; Worden, S. P.
1971BAAS....3R.439T Altcode:
No abstract at ADS