Author name code: haisch
ADS astronomy entries on 2022-09-14
author:"Haisch, Bernard M."
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Title: The Cosmos Portal and the IYA2009 Project
Authors: Haisch, Bernard M.; Sims, M.; Lindblom, J.
Bibcode: 2009AAS...21440001H
Altcode:
In 2007 the non-profit Digital Universe Foundation (DUF) launched the
Earth Portal (earthportal.org) as a comprehensive resource for timely,
objective, science-based information about the environment. There are
currently over 1000 scholars from 60 countries engaged in this rapidly
growing web-based collaboration. The Cosmos Portal is the second major
DUF initiative (cosmosportal.org). In support of the IYA2009 effort, the
Cosmos Portal is recruiting astronomy professionals to make use of easy
online tools to publish articles, blogs, news items, image galleries,
class notes, lectures, powerpoint presentations, links to other high
quality websites or other educational material. A major difference
between the Digital Universe and Wikipedia is that educational material
is produced by identified experts, not anonymous contributors with
unknown qualifications. The Digital Universe is a 501(c)(3) public
charity whose goal is to evolve into a worldwide online community
(a social network) whose centerpiece is an ever growing Asimov-Sagan
Encyclopedia Galactica created by experts. We encourage you to write
an encylopedia article or start a portal on your favorite topic or
join an existing topic as an expert contributor.
Title: The Cosmos Portal and the IYA2009 Project
Authors: Haisch, Bernard M.; Sims, M.; Lindblom, J.
Bibcode: 2009AAS...21346508H
Altcode: 2009BAAS...41..413H
In 2007 the non-profit Digital Universe Foundation (DUF) launched
the Earth Portal as a comprehensive resource for timely, objective,
science-based information about the environment. There are currently
over 1000 scholars from 60 countries engaged in this rapidly growing
web-based collaboration. The Cosmos Portal is the second major DUF
initiative (digitaluniverse.net/cosmos). In support of the IYA2009
effort, the Cosmos Portal is recruiting astronomy professionals to
make use of easy online tools to publish articles, blogs, news items,
image galleries, class notes, lectures, powerpoint presentations,
links to other high quality websites or other educational material. In
parallel we intend to bring hundreds of amateur astronomy organizations
and thousands of amateur astronomers and telescope makers together in
a community of portals (digitaluniverse.net/cosmoscommunity). This
will allow vibrant online collaboration and information sharing. We
encourage you to start a portal on your favorite topic or join an
existing topic as a contributor.
Title: Astronomy in the Digital Universe
Authors: Haisch, Bernard M.; Lindblom, J.; Terzian, Y.
Bibcode: 2006AAS...209.9402H
Altcode: 2006BAAS...38.1031H
The Digital Universe is an Internet project whose mission is to provide
free, accurate, unbiased information covering all aspects of human
knowledge, and to inspire humans to learn, make use of, and expand this
knowledge. It is planned to be a decades long effort, inspired by the
Encyclopedia Galactica concept popularized by Carl Sagan, and is being
developed by the non-profit Digital Universe Foundation. A worldwide
network of experts is responsible for selecting content featured
within the Digital Universe. The first publicly available content
is the Encyclopedia of Earth, a Boston University project headed by
Prof. Cutler Cleveland, which will be part of the Earth Portal. The
second major content area will be an analogous Encyclopedia of the
Cosmos to be part of the Cosmos Portal. It is anticipated that this will
evolve into a major resource for astronomy education. Authors and topic
editors are now being recruited for the Encyclopedia of the Cosmos.
Title: Review of Experimental Concepts for Studying the Quantum
Vacuum Field
Authors: Davis, E. W.; Teofilo, V. L.; Haisch, B.; Puthoff, H. E.;
Nickisch, L. J.; Rueda, A.; Cole, D. C.
Bibcode: 2006AIPC..813.1390D
Altcode:
We review concepts that provide an experimental framework for exploring
the possibility and limitations of accessing energy from the space
vacuum environment. Quantum electrodynamics (QED) and stochastic
electrodynamics (SED) are the theoretical approaches guiding this
experimental investigation. This investigation explores the question
of whether the quantum vacuum field contains useful energy that can be
exploited for applications under the action of a catalyst, or cavity
structure, so that energy conservation is not violated. This is similar
to the same technical problem at about the same level of technology
as that faced by early nuclear energy pioneers who searched for, and
successfully discovered, the unique material structure that caused
the release of nuclear energy via the neutron chain reaction.
Title: Gravity and the quantum vacuum inertia hypothesis
Authors: Rueda, A.; Haisch, B.
Bibcode: 2005AnP...517..479R
Altcode: 2005gr.qc.....4061R; 2005AnP....14..479R
In previous work it has been shown that the electromagnetic quantum
vacuum, or electromagnetic zero-point field, makes a contribution to
the inertial reaction force on an accelerated object. We show that
the result for inertial mass can be extended to passive gravitational
mass. As a consequence the weak equivalence principle, which equates
inertial to passive gravitational mass, appears to be explainable. This
in turn leads to a straightforward derivation of the classical Newtonian
gravitational force. We call the inertia and gravitation connection
with the vacuum fields the quantum vacuum inertia hypothesis. To date
only the electromagnetic field has been considered. It remains to
extend the hypothesis to the effects of the vacuum fields of the other
interactions. We propose an idealized experiment involving a cavity
resonator which, in principle, would test the hypothesis for the simple
case in which only electromagnetic interactions are involved. This
test also suggests a basis for the free parameter $\eta(\nu)$ which we
have previously defined to parametrize the interaction between charge
and the electromagnetic zero-point field contributing to the inertial
mass of a particle or object.
Title: The Virtual Cosmos Project: Astronomical Data access for
General Public via the National Virtual Observatory
Authors: Craig, N.; Mendez, B. J.; Hanisch, R. J.; Christian, C. A.;
Summers, F.; Haisch, B.; Lindblom, J.
Bibcode: 2005AAS...206.0509C
Altcode: 2005BAAS...37..435C
We will describe the development of protocols to make Astronomy
press-release quality images from HST and other sources publicly
available through compatibility with the National Virtual Observatory
(NVO). We will present the designs for a public portal to these
resources, based on a robust evaluation of our intended audience. The
availability of press-release quality materials via the NVO through
a simplified interface will greatly enhance the utility of these
materials for the public. Behind any portal to NVO data there is a
standard registry and data structures that allow collections of data
(such as the press release images) to be located and acquired. We will
describe our design of the necessary protocols and metadata being used
within the NVO framework for this project. We base our meta-tags on
the considerable existing work done in the science community as well
as the NASA education community. These refined metadata are applied
to new HST press-release images as they are produced and registered
with the NVO. We will describe methods for retrofitting pre-existing
imagery with the metadata standards. The rich media, 3D navigation and
visualization capabilities of the browser created by ManyOne Network
Inc. are particularly well suited to the presentation of astronomical
information and ever more detailed models of the local neighborhood,
the Milky Way, etc. We will discuss the 3D navigation and visualization
capabilities of the browser with particular focus on the Milky Way
Galaxy. Development of an online encyclopedia to accompany the ManyOne
portals as part of the Virtual Cosmos will also be described. Support
from NASA's AISR Program is gratefully acknowledged.
Title: Inflation-Theory Implications for Extraterrestrial Visitation
Authors: Deardoff, J.; Haisch, B.; Maccabee, B.; Puthoff, H. E.
Bibcode: 2005JBIS...58...43D
Altcode:
It has recently been argued that anthropic reasoning applied to
inflation theory reinforces the prediction that we should find ourselves
part of a large, galaxy-sized civilisation, thus strengthening Fermi's
paradox concerning `Where are they?' Furthermore, superstring and
M-brane theory allow for the possibility of parallel universes, some of
which in principle could be habitable. In addition, discussion of such
exotic transport concepts as `traversable wormholes' now appears in the
rigorous physics literature. As a result, the `We are alone' solution
to Fermi's paradox, based on the constraints of earlier 20th century
viewpoints, appears today to be inconsistent with new developments
in our best current physics and astrophysics theories. Therefore we
reexamine and reevaluate the present assumption that extraterrestrials
or their probes are not in the vicinity of Earth, and argue instead that
some evidence of their presence might be found in certain high-quality
UFO reports. This study follows up on previous arguments that (1)
interstellar travel for advanced civilizations is not a priori ruled
out by physical principles and therefore may be practicable, and (2)
such advanced civilisations may value the search for knowledge from
uncontaminated species more than direct, interspecies communication,
thereby accounting for apparent covertness regarding their presence.
Title: The Digital Universe Coalition: Building a Prototype NVO
E/PO Portal
Authors: Mendez, B.; Craig, N.; Haisch, B.; Lindblom, J.; Hanisch,
R.; Summers, F.; Abbott, B.
Bibcode: 2004AAS...204.7805M
Altcode: 2004BAAS...36..810M
The National Virtual Observatory (NVO) holds tremendous potential for
Education and Public Outreach (E/PO) opportunities. The possibilities
for E/PO with the NVO, which promises to make widely available the
great majority of the world's astronomical data, are too numerous for
any one E/PO effort to ever hope to develop. Therefore, it is critical
that the NVO E/PO program develop an infrastructure and tools flexible
enough that any E/PO program can make use of it. In response to the
recommendations of the NVO science definition team, UC Berkeley's SEGway
program conducted needs assessment surveys of potential non-traditional
(i.e. non-scientist) NVO user communities. The SEGway team wished to
use the results of these surveys to design a demonstration website
that could show some of the potential capabilities of NVO E/PO. SEGway
established an informal partnership with STScI, AMNH/Hayden Planetarium,
and ManyOne Network to explore how to assemble the infrastructure
and tools for NVO E/PO and to construct a demonstration portal that
makes use of NVO resources. We called this partnership The Digital
Universe Coalition. This prototype displays AMNH/Hayden's Digital
Universe star catalog of approximately 100,000 stars, based largely
on HIPPARCOS parallaxes, in a virtual three-dimensional space. Three
types of user-interactive data display and/or navigation are possible:
an Earth-based view of the sky with the option of displaying
constellations; a spaceship-based view moving through space; and a
"god's-eye" view of the local neighborhood from an external vantage
point. One key feature of this demo is the linking of user-selectable
locations in the sky to the online Digitized Sky Survey data sets. A
second feature is a set of links for educational content on a handful of
selected objects. Both of these capabilities will be extended further
as we plan to begin development of a much more robust and complete
E/PO portal for the NVO.
Title: Update on an Electromagnetic Basis for Inertia, Gravitation,
the Principle of Equivalence, Spin and Particle Mass Ratios
Authors: Haisch, Bernard; Rueda, Alfonso; Nickisch, L. J.; Mollere,
Jules
Bibcode: 2003AIPC..654..922H
Altcode: 2002gr.qc.....9016H
A possible connection between the electromagnetic quantum vacuum and
inertia was first published by Haisch, Rueda and Puthoff (1994). If
correct, this would imply that mass may be an electromagnetic
phenomenon and thus in principle subject to modification, with possible
technological implications for propulsion. A multiyear NASA-funded study
at the Lockheed Martin Advanced Technology Center further developed
this concept, resulting in an independent theoretical validation of
the fundamental approach (Rueda and Haisch, 1998ab). Distortion of the
quantum vacuum in accelerated reference frames results in a force that
appears to account for inertia. We have now shown that the same effect
occurs in a region of curved spacetime, thus elucidating the origin
of the principle of equivalence (Rueda, Haisch and Tung, 2001). A
further connection with general relativity has been drawn by Nickisch
and Mollere (2002): zero-point fluctuations give rise to spacetime
micro-curvature effects yielding a complementary perspective on the
origin of inertia. Numerical simulations of this effect demonstrate
the manner in which a massless fundamental particle, e.g. an electron,
acquires inertial properties; this also shows the apparent origin of
particle spin along lines originally proposed by Schroedinger. Finally,
we suggest that the heavier leptons (muon and tau) may be explainable
as spatial-harmonic resonances of the (fundamental) electron. They
would carry the same overall charge, but with the charge now having
spatially lobed structure, each lobe of which would respond to higher
frequency components of the electromagnetic quantum vacuum, thereby
increasing the inertia and thus manifesting a heavier mass.
Title: The Inertia Reaction Force and Its Vacuum Origin
Authors: Rueda, Alfonso; Haisch, Bernard
Bibcode: 2003grco.book..447R
Altcode:
By means of a covariant approach we show that there must be a
contribution to the inertial mass and to the inertial reaction force
on an accelerated massive object by the zero-point electromagnetic
field. This development does not require any detailed model of
the accelerated object other than the knowledge that it interacts
electromagnetically. It is shown that inertia can indeed be construed
as an opposition of the vacuum fields to any change to the uniform
state of motion of an object. Interesting insights originating from
this result are discussed. It is argued why the proposed existence
of a Higgs field in no way contradicts or is at odds with the above
statements. The Higgs field is responsible for assigning mass to
elementary particles. It is argued that still the underlying reason for
the opposition to acceleration that massive objects present requires
an explanation. The explanation proposed here fulfills that requirement.
Title: A Lot of Observations of the Coronae of AR Lac
Authors: Pease, D.; Drake, J. J.; Kashyap, V.; Ratzlaff, P. W.; Saar,
S.; Haisch, B.; Dobrzycki, A.; Adams, N. R.; Wolk, S. J.
Bibcode: 2002ASPC..277..551P
Altcode: 2002sccx.conf..551P
No abstract at ADS
Title: The Inertia Reaction Force and its Vacuum Origin
Authors: Rueda, Alfonso; Haisch, Bernard
Bibcode: 2002gchr.conf..447R
Altcode:
No abstract at ADS
Title: Gravity and the Quantum Vacuum Inertia
Hypothesis. I. Formalized Groundwork for Extension to Gravity
Authors: Rueda, Alfonso; Haisch, Bernard; Tung, Roh
Bibcode: 2001gr.qc.....8026R
Altcode:
It has been shown [1,2] that the electromagnetic quantum vacuum makes
a contribution to the inertial mass, $m_i$, in the sense that at least
part of the inertial force of opposition to acceleration, or inertia
reaction force, springs from the electromagnetic quantum vacuum. As
experienced in a Rindler constant acceleration frame the electromagnetic
quantum vacuum mainfests an energy-momentum flux which we call the
Rindler flux (RF). The RF, and its relative, Unruh-Davies radiation,
both stem from event-horizon effects in accelerating reference
frames. The force of radiation pressure produced by the RF proves to be
proportional to the acceleration of the reference frame, which leads to
the hypothesis that at least part of the inertia of an object should
be due to the interaction of its quarks and electrons with the RF. We
demonstrate that this quantum vacuum inertia hypothesis is consistent
with general relativity (GR) and that it answers a fundamental question
left open within GR, viz. is there a physical mechanism that generates
the reaction force known as weight when a specific non-geodesic motion
is imposed on an object? The quantum vacuum inertia hypothesis provides
such a mechanism, since by assuming the Einstein principle of local
Lorentz-invariance (LLI), we can immediately show that the same RF
arises due to curved spacetime geometry as for acceleration in flat
spactime. Thus the previously derived expression for the inertial mass
contribution from the electromagnetic quantum vacuum field is exactly
equal to the corresponding contribution to the gravitational mass,
$m_g$. Therefore, within the electromagnetic quantum vacuum viewpoint
proposed in [1,2], the Newtonian weak equivalence principle, $m_i=m_g$,
ensues in a straightforward manner.
Title: Geometrodynamics, Inertia and the Quantum Vacuum
Authors: Haisch, Bernard; Rueda, Alfonso
Bibcode: 2001gr.qc.....6075H
Altcode:
Why does {\bf F} equal m{\bf a} in Newton's equation of motion? How
does a gravitational field produce a force? Why are inertial mass
and gravitational mass the same? It appears that all three of
these seemingly axiomatic foundational questions have an answer
involving an identical physical process: interaction between the
electromagnetic quantum vacuum and the fundamental charged particles
(quarks and electrons) constituting matter. All three of these effects
and equalities can be traced back to the appearance of a specific
asymmetry in the otherwise uniform and isotropic electromagnetic
quantum vacuum. This asymmetry gives rise to a non-zero Poynting vector
from the perspective of an accelerating object. We call the resulting
energy-momentum flux the {\it Rindler flux}. The key insight is that
the asymmetry in an accelerating reference frame in flat spacetime
is identical to that in a stationary reference frame (one that is
not falling) in curved spacetime. Therefore the same Rindler flux
that creates inertial reaction forces also creates weight. All of
this is consistent with the conceptualizaton and formalism of general
relativity. What this view adds to physics is insight into a specific
physical process creating identical inertial and gravitational forces
from which springs the weak principle of equivalence. What this view
hints at in terms of advanced propulsion technology is the possibility
that by locally modifying either the electromagnetic quantum vacuum
and/or its interaction with matter, inertial and gravitational forces
could be modified.
Title: Inertial mass and the quantum vacuum fields
Authors: Haisch, Bernard; Rueda, Alfonso; Dobyns, York
Bibcode: 2001AnP...513..393H
Altcode: 2001AnP....10..393H; 2000gr.qc.....9036H
Even when the Higgs particle is finally detected, it will continue
to be a legitimate question to ask whether the inertia of matter as
a reaction force opposing acceleration is an intrinsic or extrinsic
property of matter. General relativity specifies which geodesic path a
free particle will follow, but geometrodynamics has no mechanism for
generating a reaction force for deviation from geodesic motion. We
discuss a different approach involving the electromagnetic zero-point
field (ZPF) of the quantum vacuum. It has been found that certain
asymmetries arise in the ZPF as perceived from an accelerating reference
frame. In such a frame the Poynting vector and momentum flux of the ZPF
become non-zero. Scattering of this quantum radiation by the quarks and
electrons in matter can result in an acceleration-dependent reaction
force. Both the ordinary and the relativistic forms of Newton's second
law, the equation of motion, can be derived from the electrodynamics
of such ZPF-particle interactions. Conjectural arguments are given
why this interaction should take place in a resonance at the Compton
frequency, and how this could simultaneously provide a physical basis
for the de Broglie wavelength of a moving particle. This affords a
suggestive perspective on a deep connection between electrodynamics,
the origin of inertia and the quantum wave nature of matter.
Title: How to Abhor the Void While Loving the Quantum Vacuum
Authors: Haisch, Bernard; Rueda, Alfonso
Bibcode: 2000Mercu..29e..32H
Altcode:
Getting to another star in a human lifetime right now seems impossible,
but intriguing physics offers us some fantastic possibilities to
consider.
Title: Prospects for an Interstellar Mission: Hard Technology Limits
but Surprising Physics Possibilities
Authors: Haisch, Bernard; Rueda, Alfonso
Bibcode: 2000Mercu..29d..26H
Altcode:
How can we reach another star in a timely fashion? Extrapolating our
best current technology into the future is like trying to somehow
soup-up Magellan's sailing ship to circumnavigate the globe in ninety
minutes.
Title: On the relation between a zero-point-field-induced inertial
effect and the Einstein-de Broglie formula
Authors: Haisch, Bernard; Rueda, Alfonso
Bibcode: 2000PhLA..268..224H
Altcode: 1999gr.qc.....6084H
It has been proposed that the scattering of electromagnetic zero-point
radiation by accelerating objects results in a reaction force
that may account, at least in part, for inertia [1-3]. This arises
because of asymmetries in the electromagnetic zero-point field (ZPF)
or electromagnetic quantum vacuum as perceived from an accelerating
reference frame. In such a frame, the Poynting vector and momentum
flux of the ZPF become non-zero. If one assumes that scattering of
the ZPF radiation takes place at the level of quarks and electrons
constituting matter, then it is possible for both Newton's equation of
motion, f=ma, and its relativistic covariant generalization, F=dP/dτ,
to be obtained as a consequence of the non-zero ZPF momentum flux. We
now conjecture that this scattering must take place at the Compton
frequency of a particle, and that this interpretation of mass leads
directly to the de Broglie relation characterizing the wave nature of
that particle in motion, λB=h/p. This suggests a perspective
on a connection between electrodynamics and the quantum wave nature
of matter. Attempts to extend this perspective to other aspects of
the vacuum are left for future consideration.
Title: The Case for Inertia as a Vacuum Effect: A Reply to Woodward
and Mahood
Authors: Dobyns, York; Rueda, Alfonso; Haisch, Bernard
Bibcode: 2000gr.qc.....2069D
Altcode:
The possibility of an extrinsic origin for inertial reaction forces has
recently seen increased attention in the physical literature. Among
theories of extrinsic inertia, the two considered by the current
work are (1) the hypothesis that inertia is a result of gravitational
interactions, and (2) the hypothesis that inertial reaction forces arise
from the interaction of material particles with local fluctuations
of the quantum vacuum. A recent article supporting the former and
criticizing the latter is shown to contain substantial errors.
Title: Physical Requirements for Flares in Stars
Authors: Haisch, B.
Bibcode: 2000ASPC..214..304H
Altcode: 2000bpet.conf..304H; 2000IAUCo.175..304H
No abstract at ADS
Title: Solar-Stellar Connection
Authors: Haisch, B. M.
Bibcode: 1999mfs..conf..481H
Altcode:
Stellar Coronae and Acoustic Heating The Dividing Line the
Rotation-Activity Relation: Calibrating the Dynamo Age Versus Activity:
The Evolution of the Sun Stellar Activity Cycles Mapping Stellar
Surfaces Flares on Other Stars What is the Range of Stellar Power
Ratios? Conclusion
Title: Active Regions
Authors: Holman, G. D.; Cheng, C. -C.; Gurman, J. B.; Haisch, B. M.;
Poland, A. I.; Porter, J. G.; Saba, J. L. R.; Schmieder, B.; Strong,
K. T.
Bibcode: 1999mfs..conf...41H
Altcode:
Magnetic Field Strength and Strucutre Results Prior to SMM First Results
with SMM Subsequent Results: 1983-1987 The Coronal Magnetic Structures
Observing Campaign Coronal Magnetic Field Studies after SMM Dynamics
and Heating of the Solar Corona FCS Line-Broadening Measurements
Large Nonthermal Velocities Spatial Variations Correlation Studies FCS
Line-Broadening Data Interpreting the FCS Line Broadening Constraints
on Mass Motions Link to Heating Discussion Coronal Heating, Magnetic
Fields, and Flares UVSP Obervations of Active Regions Transition Region
Brightenings: UV Microflares Sunspots Magnetic Field and Height of the
Transition Region Sunspot Plumes Sunspot Flows Horizontal Flows Vertical
Flows Nonthermal Line Broadening Umbral Oscillations A Look Backward,
a Look Forward Prominences and Filaments Prominence Environment and
Structure Steady Flows in Prominence Material Activity in Prominences
Postflare Loops and Surges Conclusion
Title: A Geosynchronous 2.4-meter UV/Optical Astrophysical Observatory
Authors: Haisch, B.; Robb, P.; Strong, K.; Shemansky, D.
Bibcode: 1999ASPC..164..279H
Altcode: 1999uosa.conf..279H
No abstract at ADS
Title: Design for a low-cost, 2.4-meter, geosynchronous UV Observatory
Authors: Haisch, B.; Robb, P.; Strong, K.; Shemansky, D.
Bibcode: 1998AAS...192.8003H
Altcode: 1998BAAS...30..935H
Studies were initiated in 1995 at the Lockheed Martin Advanced
Technology Center in Palo Alto to explore both the application of new
technologies and the economical utilization of commercial products to
the design of a new generation of scientific research satellites. A
2.4-meter Solar System Observatory (SSO) has been designed to carry
out as its primary mission imaging and spectroscopy of comets and
of the outer planets from geosynchronous orbit. Such a Hubble-class
telescope with a science payload consisting of four UV/EUV spectrographs
(wavelength range 550-3200 Angstroms , spectral resolution up to 20000)
and a high-resolution imager having 0.06 arcsec spatial resolution
can now be built and launched within the budget of a NASA Discovery
Mission. Following a one-year science program under the direction of the
principal investigator, the SSO would transition to a guest observer
facility. Although optimized for cometary and planetary measurements
in the UV/EUV, SSO would have outstanding capability for a variety
of astrophysical measurements in the UV. SSO would also serve as a
prototype for other similar low-cost space observatories that could
be optimized for stellar, extragalactic and other applications.
Title: A Telescope Design for Direct Imaging of Extrasolar Planets
Authors: Robb, P.; Bandermann, L.; Haisch, B.; Strong, K.
Bibcode: 1998AAS...192.8004R
Altcode: 1998BAAS...30..935R
We report on the design of a 2.0-meter orbiting telescope capable of
detection by direct imaging of Jupiter-class planets around solar-type
stars at a distance of up to 10 parsecs. The telescope would operate
in the visible spectrum, using reflected light to maximize angular
resolution. An off-axis Gregorian telescope with field and Lyot
stops has been designed using low-scatter mirror surfaces and optical
apodization to control diffraction. Calculations indicate that the
system will reliably detect Jupiter- and Saturn-class planets around
solar-type stars at angular separations as small as 0.5 arcsec. Such
a single-telescope system would fit within the constraints of a
Discovery or MIDEX NASA program, and would serve as a pathfinder for
large space-based interferometric systems.
Title: The Zero-Point Field and Inertia
Authors: Haisch, B.; Rueda, A.
Bibcode: 1998clmp.conf..171H
Altcode: 1999gr.qc.....8057H
A brief overview is presented of the basis of the electromagnetic
zero-point field in quantum physics and its representation in stochastic
electrodynamics. Two approaches have led to the proposal that the
inertia of matter may be explained as an electromagnetic reaction
force. The first is based on the modeling of quarks and electrons
as Planck oscillators and the method of Einstein and Hopf to treat
the interaction of the zero-point field with such oscillators. The
second approach is based on analysis of the Poynting vector of the
zero-point field in accelerated reference frames. It is possible to
derive both Newton's equation of motion, F=ma, and its relativistic
co-variant form from Maxwell's equations as applied to the zero-point
field of the quantum vacuum. This appears to account, at least in part,
for the inertia of matter.
Title: Electromagnetic Vacuum and Inertial Mass
Authors: Rueda, A.; Haisch, B.
Bibcode: 1998clmp.conf..179R
Altcode:
No abstract at ADS
Title: A Close Look at the Coronal Density of Procyon
Authors: Schmitt, J. H. M. M.; Drake, J. J.; Haisch, B. M.; Stern,
R. A.
Bibcode: 1996ApJ...467..841S
Altcode:
We derive the coronal density of the nearby star Procyon, using an
observation with the short- and medium-wavelength spectrometers on board
the Extreme-Ultraviolet Explorer satellite (EUVE). Specifically, we have
identified density-sensitive ratios in lines due to iron in ionization
stages Fe X to Fe XIV, which have been detected in our EUVE spectra. We
present these observations and analyze these line ratios, paying careful
attention to line blends or contamination from other extreme-ultraviolet
(EUV) lines. We show that all the available density-sensitive
iron line diagnostics are consistent with the interpretation that
the overall coronal output of Procyon is dominated by regions with a
coronal density very much resembling densities typically found in active
regions on the Sun. We estimate that the corona of Procyon is dominated
by material at a temperature Tcor ∼ 106.2 K,
with no significant amount of material above T ∼ 106.8
K; the characteristic density is ne ∼ 3 x 109
cm-3 the emission measure is EM ∼ 4.5 × 1050
cm-3. We infer a (visible) volume of Vtot ∼ 5
x 1031 cm-3 assuming the X-ray emission to arise
from plasma magnetically confined in loops, we deduce that such loops
have an average height of h ∼ 2 x 109 cm and cover about
20% of the stellar surface. Because of the high coronal density and
the lack of emission measure substantially below T ∼ 106
K, we conclude also that it is unlikely that there exists a cooler,
acoustically heated subcorona.
Title: Flare energetics: analysis of a large flare on YZ Canis
Minoris observed simultaneously in the ultraviolet, optical and radio.
Authors: van den Oord, G. H. J.; Doyle, J. G.; Rodono, M.; Gary,
D. E.; Henry, G. W.; Byrne, P. B.; Linsky, J. L.; Haisch, B. M.;
Pagano, I.; Leto, G.
Bibcode: 1996A&A...310..908V
Altcode:
The results of coordinated observations of the dMe star YZ CMi
at optical, UV and radio wavelengths during 3-7 February 1983 are
presented. YZ CMi showed repeated optical flaring with the largest
flare having a magnitude of 3.8 in the U-band. This flare coincided
with an IUE exposure which permits a comparison of the emission measure
curves of YZ CMi in its flaring and quiescent state. During the flare a
downward shift of the transition zone is observed while the radiative
losses in the range 10^4^-10^7^K strongly increase. The optical flare
is accompanied with a radio flare at 6cm, while at 20cm no emission
is detected. The flare is interpreted in terms of optically thick
synchrotron emission. We present a combined interpretation of the
optical/radio flare and show that the flare can be interpreted within
the context of solar two-ribbon/white-light flares. Special attention
is paid to the bombardment of dMe atmospheres by particle beams. We
show that the characteristic temperature of the heated atmosphere is
almost independent of the beam flux and lies within the range of solar
white-light flare temperatures. We also show that it is unlikely that
stellar flares emit black-body spectra. The fraction of accelerated
particles, as follows from our combined optical/radio interpretation
is in good agreement with the fraction determined by two-ribbon flare
reconnection models.
Title: The Extreme-Ultraviolet Spectrum of the Nearby K Dwarf
ɛ Eridani
Authors: Schmitt, J. H. M. M.; Drake, J. J.; Stern, R. A.; Haisch,
B. M.
Bibcode: 1996ApJ...457..882S
Altcode:
We present and discuss the extreme-ultraviolet spectrum of the
nearby K2 dwarf ɛ Eri obtained with the spectrometers onboard the
Extreme-Ultraviolet Explorer satellite (EUVE). In the EUVE spectrum of
ɛ Eri we detect emission lines attributable to iron in the ionization
stages Fe IX to Fe XXI, thus covering a rather large temperature range
from less than 106 K to 107 K. While the lines
in the lowest and highest ionization stages are relatively weak, the
strongest lines detected are from Fe XV and Fe XVI, from which we infer
a peak in the differential emission measure distribution at coronal
temperatures of log Tc ∼ 6.4; significant emission measure
is, however, also present at both higher and lower temperatures. This
is in contrast to both lower activity stars whose EUV spectra are
dominated by cooler Fe lines in the range 170-180 Å as well as the
more active stars whose EUV spectra are dominated by hotter Fe lines
in the range 110-135 Å. Finally, a density determination using line
ratios of Fe XIII and Fe XIV results in coronal densities for ɛ Eri
which are similar to solar active region densities.
Title: Stellar X-ray Flares
Authors: Haisch, B.
Bibcode: 1996mpsa.conf..235H
Altcode: 1996IAUCo.153..235H
No abstract at ADS
Title: A U.S.--Russian Industrial Partnership to Develop a Low-Cost
IUE-2
Authors: Haisch, B.; Robb, P.; Strong, K.; Stern, R.; Schrijver,
C. J.; Lemen, J.
Bibcode: 1995AAS...187.7204H
Altcode: 1995BAAS...27.1388H
In 18 years as a NASA observatory IUE has generated more than 10(5)
spectra and 3000 articles, hosted over 2000 guest observers and launched
more than 200 doctoral dissertations. On 1 October 1995 science
operations were transferred entirely to ESA. IUE has been a central
facility in many multiwavelength programs. It has also supported
HST by carrying out projects that require more dedicated time than
HST can accomodate, including the ability to carry out uninterrupted
observations. Ready access to the UV spectrum has become a routine part
of modern astronomical capability, especially with respect to surveying
classes of objects and monitoring for variability and cycles. A
feasibility study has been initiated in the Solar and Astrophysics
Laboratory and the Optical Sciences Laboratory to examine an upgraded
IUE-2 to be developed in partnership with the Vavilov State Optical
Institute of St. Petersburg, Russia. The Vavilov Institute is the
premier space optics facility in the former Soviet Union. The recent
``swords into plowshares'' industrial partnership with Vavilov and
cost-effective capabilities involving commercial boosters such as LLV-2
and a version of the Commercial Remote Sensing Satellite (CRSS) bus
open innovative new opportunities for developing scientific facilities
in space. We are also investigating the economics of a shared launch on
the large capacity Proton rocket now operated jointly at the Baikonur
complex in Kazakhstan by Lockheed Martin, Khrunichev Enterprises and
NPO Energia. The centerpiece of IUE-2 would be a lightweight, advanced
techology silicon carbide mirror up to 1.2 m in diameter coupled to
modern imaging detectors. The Vavilov Institute has developed a robust
ceramic material of remarkable specific rigidity and thermal stability
that shows no distortion or hysteresis when thermally cycled between
cryogenic and room temperatures. Mirrors are routinely polished
to 0.03 waves in the visible. Spectroscopic capabilities would be
similar to the current IUE. The CRSS spacecraft provides 10 GBytes
of onboard data storage. In the interest of cost-savings, a highly
eccentric Exosat-like elliptical orbit is under consideration to
provide uninterrupted viewing times of at least 12 hours. This study,
now underway, will examine innovative ways in which a science-driven
program can be successfully developed and provided to NASA as a
purchased commercial product. Inputs are solicited, especially from
IUE guest observers and potentially interested IUE-2 users.
Title: Stellar M-Flares Observed by ASCA on Proxima Centauri
Authors: Haisch, B.; Antunes, M.; Schmitt, J. H. M. M.
Bibcode: 1995SPD....26.1307H
Altcode: 1995BAAS...27..988H
No abstract at ADS
Title: The Elemental Composition of the Corona of Procyon: Evidence
for the Absence of the FIP Effect
Authors: Drake, Jeremy J.; Laming, J. Martin; Widing, Kenneth G.;
Schmitt, Jurgen H. M. M.; Haisch, Bernard; Bowyer, Stuart
Bibcode: 1995Sci...267.1470D
Altcode:
The chemical composition of the solar corona is not the same as that
of the underlying photosphere. In the corona, elements with a first
ionization potential (FIP) of <= 10 electron volts (for example,
iron, magnesium, silicon, and calcium) are overabundant relative
to those with an FIP of >= 10 electron volts (for example,
oxygen, neon, and sulfur) by factors of 3 to 10 with respect to the
photosphere. The origin of this FIP effect is unknown. The launch
of the Extreme Ultraviolet Explorer Satellite (EUVE) opened up the
spectroscopic capability required to determine elemental abundances
in the coronae of other stars. Spectroscopic observations of the
corona of the nearby F5 IV star Procyon obtained with EUVE have
yielded estimates of the relative abundances of high- and low-FIP
species. The results provide evidence that Procyon, unlike the sun,
does not exhibit the FIP effect. Whether the sun or Procyon is more
typical of the general late-type stellar population is of fundamental
interest to the physics of stellar outer atmospheres and has a bearing
on the origin of cosmic rays.
Title: ASCA observations of X-ray flares on Proxima Centauri
Authors: Antunes, Alex; Haisch, B.; Schmitt, J. H. M. M.
Bibcode: 1995AAS...186.2102A
Altcode: 1995BAAS...27..838A
We present the ASCA observation of several flare events on Proxima
Centauri during March 18-20 1994. Although the quiescent count rate of
0.23 cts/sec was too low to unambiguously spot line features, flares
were clearly distinguished with a higher count rate of approximately
0.9 cts/sec. These are the first stellar flares observed to overlap
with ordinary solar flares of class M on the GOES scale (Haisch,
Antunes and Schmitt, 1995, Science, in press). We compared the
quiescent data with the flare data, and fit the X-ray emission using
two-temperature and differential emission measure plasma models. Unlike
several coronal sources (for example, Algol, AR Lac), the models did
not require sub-solar abundances. However, abundance determinations
in the absence of clearly distinguishable lines were uncertain. The
current results support the premise that the coronal X-ray emission
is a result of the superposition of many flares.
Title: The RIASS Coronathon: Joint X-Ray and Ultraviolet Observations
of Normal F--K Stars
Authors: Ayres, Thomas R.; Fleming, T. A.; Simon, T.; Haisch, B. M.;
Brown, A.; Lenz, D.; Wamsteker, W.; de Martino, D.; Gonzalez, C.;
Bonnell, J.; Mas-Hesse, J. M.; Rosso, C.; Schmitt, J. H. M. M.;
Truemper, J.; Voges, W.; Pye, J.; Dempsey, R. C.; Linsky, J. L.;
Guinan, E. F.; Harper, G. M.; Jordan, C.; Montesinos, B. M.; Pagano,
I.; Rodono, M.
Bibcode: 1995ApJS...96..223A
Altcode:
Between 1990 August and 1991 January the ROSAT/IUE All Sky Survey
(RIASS) coordinated pointings by the International Ultraviolet Explorer
(IUE) with the continuous X-ray/EUV mapping by the Roentgensatellit
(ROSAT). The campaign provided an unprecedented multiwavelength
view of a wide variety of cosmic sources. We report findings for
F-K stars, a large proportion of the RIASS targets. Forty-eight of
our 91 'Coronathon' candidates were observed by the IUE during the
campaign. For stars missed by the IUE, we supplemented the ROSAT survey
fluxes with archival UV spectra and/or follow-on observations.
Title: Stellar x-ray flares
Authors: Haisch, B.; Uchida, Y.; Kosugi, T.; Hudson, H. S.
Bibcode: 1995lock.reptR....H
Altcode:
What is the importance of stellar X-ray flares to astrophysics, or
even more, to the world at large? In the case of the Sun, changes in
solar activity at the two temporal extremes can have quite significant
consequences. Longterm changes in solar activity, such as the Maunder
Minimum, can apparently lead to non-negligible alterations of the
earth's climate. The extreme short term changes are solar flares, the
most energetic of which can cause communications disruptions, power
outages and ionizing radiation levels amounting to medical X-ray dosages
on long commercial flights and even potentially lethal exposures for
unshielded astronauts. Why does the Sun exhibit such behaviour? Even
if we had a detailed knowledge of the relevant physical processes on
the Sun - which we may be on the way to having in hand as evidenced
by these Proceedings- our understanding would remain incomplete in
regard to fundamental causation so long as we could not say whether the
Sun is, in this respect, unique among the stars. This current paper
discusses the stellar x-ray flare detections and astronomical models
(quasi-static cooling model and two-ribbon model) that are used to
observe the x-ray emission.
Title: ASCA Observations of Solar-like M-flares on Proxima Centauri
Authors: Haisch, B.; Antunes, A.; Schmitt, J. H. M. M.
Bibcode: 1994AAS...185.4505H
Altcode: 1994BAAS...26.1380H
Stellar flares have been observed in the X-ray for twenty years, but
the events must be much larger --- by as much as a factor of 10(4)
--- than even the most energetic on the Sun in order to be detected
across the enormous distances. While stellar ``superflares'' are of
considerable interest, it is equally important to ascertain whether and
with what frequency commonplace solar-like events occur on stars. This
is an important test of the working hypothesis that we are dealing with
scaled-up versions of the same physical phenomenon. The new Japanese
ASCA satellite has now succeeded in this, observing very typical
M-class solar-like flares on the next nearest star, Proxima Centauri.
Title: A Spectroscopic Measurement of the Coronal Density of Procyon
Authors: Schmitt, J. H. M. M.; Haisch, B. M.; Drake, J. J.
Bibcode: 1994Sci...265.1420S
Altcode:
One of the open key issues in the astrophysics of stellar coronae is the
determination of their spatial structure and density. From almost all
previous measurements, one can infer merely the presence of a corona,
which for the most energetic stellar coronae may exceed the solar x-ray
output by as much as five orders of magnitude, but no information can be
obtained on the densities and hence volumes and sizes of the hot x-ray
emitting material. A direct spectroscopic measurement of the coronal
density was obtained for the star Procyon with the spectrometer on
board the Extreme Ultraviolet Explorer satellite; the ratio of two
Fe XIV lines at 211.32 and 264.79 angstroms was used to determine
a density of ~4 x 10^9 to 7 x 10^9 electrons per cubic centimeter,
which is a factor of 2 to 3 higher than typical solar active region
densities. From this value, we estimate that ~6 percent of the stellar
surface is covered with ~7 x 10^4 coronal loops.
Title: The First Measurement of Stellar Coronal Abundances: The
Absence of the FIP Effect in the Corona of Procyon
Authors: Drake, J. J.; Laming, J. M.; Widing, K. G.; Schmitt,
J. H. M. M.; Haisch, B.; Bowyer, S.
Bibcode: 1994AAS...184.0522D
Altcode: 1994BAAS...26..866D
The unique spectroscopic capabilities of the Extreme Ultraviolet
Explorer satellite (EUVE), with wavelength coverage from 70--760
Angstroms at a resolution of ~ 1 Angstroms, permit for the first time
the scrutiny in the extreme ultraviolet wavelength regime of individual
spectral lines emitted by the coronae of stars other than the Sun. We
have performed a detailed analysis of the first EUVE spectroscopic
observation of the nearby F5 IV star Procyon and have identified
lines of the elements O, Ne, Mg, Si, S, Fe, and Ni. The emission
measure distribution, derived from line intensities measured from the
EUVE spectra and based on the most recent atomic data, has yielded
estimates of the relative abundances of these elements in the corona
of Procyon. The results indicate a total absence of a fractionation of
elements by first ionization potential (FIP), contrary to such as is
observed in the solar corona (the ``FIP Effect''). These results are
discussed, and the potential for future EUVE spectroscopic investigation
into the new field of stellar coronal abundances is highlighted. This
work has been supported by NASA contract NAS5-30180.
Title: EUVE Spectroscopy of XI UMa; sigma Gem; and Chi {1} ORI
Authors: Mewe, R.; Schrijver, C. J.; Kaastra, J. S.; Alkemade,
F. J. M.; Haisch, B. M.
Bibcode: 1994ASPC...64...41M
Altcode: 1994csss....8...41M
No abstract at ADS
Title: Observing a partly cloudy universe.
Authors: Bowyer, S.; Malina, R.; Haisch, B.
Bibcode: 1994S&T....88f..36B
Altcode:
No abstract at ADS
Title: The High-Energy View of the Nearby Star Procyon
Authors: Schmitt, J. H. M. M.; Haisch, B. M.; Drake, J. J.
Bibcode: 1994HEAD...26...13S
Altcode:
No abstract at ADS
Title: Impulsive Soft X-ray Bursts on the Flare Star UV Ceti
Authors: Haisch, B.; Schmitt, J. H. M. M.; Barwig, H.
Bibcode: 1993AAS...18312303H
Altcode: 1993BAAS...25R1475H
We report on a new and unexpected impulsive phenomenon during two
stellar flares simultaneously observed in soft X-rays by the ROSAT
Observatory and using ground-based, high-speed optical photometry at
the Wendelstein Observatory in Bavaria, Germany. SXR bursts follow
the U- and B-band events by approximately 30 s. We concentrate on
the correlation of the optical and initial SXR bursts. Statistical
analysis verifies the significance of these events. They may offer
an unexpected window on the impulsive phase of stellar flares. This
would be especially timely since the ASCA Observatory has just begun
its mission and should be capable of observing stellar flares in some
detail. While the precise physical implications of our observations
remain unclear, we argue that our data show the signature of X-ray
emission from the impulsive phase of a stellar flare rather than that
of a microflare or a compact loop flare. The curious time relationship
between the optical and SXR bursts may lend support to a gas-dynamic
model proposed by Katsova and Livshits.
Title: Implications of Initial Results from the EUVE Observatory
for the FUSE EUV Spectrometer and a Possible EUVE Extended Mission
Authors: Malina, R. F.; Finley, D.; Warren, J.; Fruscione, A.;
Edelstein, J.; Haisch, B.
Bibcode: 1993AAS...183.1716M
Altcode: 1993BAAS...25.1320M
We summarize the initial scientific results from the Extreme
Ultraviolet Explorer (EUVE) observatory all-sky survey and Guest
Observer Programs. The initial results include the first EUVE catalog
(Bowyer et al. 1993) which reports characteristics of 410 extreme
ultraviolet (EUV) sources and the spectroscopic observations by
guest observers of large numbers of classes of different kinds of EUV
sources. We assess the implication of these initial results on the
scientific objectives of the EUV spectrometer on NASA's Far Ultraviolet
Spectroscopic Explorer (FUSE). The FUSE EUV spectrometer will have an
order of magnitude more collecting area than the EUVE spectrometer and a
resolving power several times higher. Current NASA planning anticipates
a turn off of the EUVE observatory following the third year of the
EUVE Guest Observer Program in 1996. A proposal is currently being
prepared for NASA, in collaboration with the EUVE Users Committee,
for an extension of the EUVE mission. Based on the EUVE results, we
raise issues which must be taken into account in designing a science
program for a possible extension of the EUVE mission such as the
total number of EUV sources observable spectroscopically by EUVE. We
distinguish between the science return from an EUVE extended mission
and from the EUV spectrometer on FUSE given the different capabilities
of the two instruments. We discuss in detail the types of scientific
investigations that can be expected for cool stars, white dwarfs,
extragalactic objects and cataclysmic variables. The work reported
here was funded by NASA Contract NAS5--29298.
Title: The Extreme Ultraviolet Explorer mission: overview and
initial results.
Authors: Haisch, B.; Bowyer, S.; Malina, R. F.
Bibcode: 1993JBIS...46R.331H
Altcode:
The successful launch of the NASA Extreme Ultraviolet Explorer on
June 7, 1992, is the culmination of nearly 30 years of effort at the
University of California at Berkeley to open up the field of extreme
ultraviolet astronomy. The authors present a brief introduction to
this field and an overview of the satellite instrumentation.
Title: The Extreme Ultraviolet Explorer mission - Overview and
initial results
Authors: Haisch, B.; Bowyer, S.; Malina, R. F.
Bibcode: 1993JBIS...46Q.331H
Altcode:
The history of extreme ultraviolet (EUV) astronomy is briefly
reviewed, and an overview of the Extreme Ultraviolet Explorer
mission, launched into a near-earth (550 km) orbit on June 7, 1992,
is presented. First, the principal objective of the mission are
summarized. The instrumentation and operation of the mission are
then described, with particular attention given to the sky survey
instruments, the deep survey instrument, and the spectrometers. The
discussion also covers the current view of the interstellar medium,
early results from the mission, and future prospects for EUV astronomy.
Title: The EUV Coronal Spectrum of chi (1) ORI (HR 2047, G0 V)
Authors: Haisch, B.; Drake, J.; Schmitt, J. H. M. M.
Bibcode: 1993AAS...182.4115H
Altcode: 1993BAAS...25..862H
We have carried out an 80 ks extreme ultraviolet observation of the
active solar-like star chi (1) Ori using the Extreme Ultraviolet
Explorer (EUVE) spectrograph. Based on its chromospheric activity
level, this star appears to be quite young (see Haisch and Basri,
1985, Ap. J. Suppl., 58, 179). Its X-ray luminosity as measured by
the Einstein IPC (log L_x = 28.8) and the ROSAT PSPC (log L_x = 29.1)
makes it a factor of ten more active than the Sun at solar maximum. We
present the first EUV spectrum of an active solar-like star.
Title: ROSAT observations of the stellar coronal dividing line.
Authors: Haisch, B.; Schmitt, J. H. M. M.
Bibcode: 1993uxrs.conf..547H
Altcode: 1993uxsa.conf..547H
The authors present an update on the results of the ROSAT X-ray All-Sky
Survey observations of stellar sources presented by Haisch, Schmitt
and Rosso (1991). In that paper the presence of a coronal dividing
line in the H-R diagram at approximately spectral type K3 II to K3
IV was established by the clear difference in distribution of the 65
ROSAT detections vs. the 868 non-detections of BSC stars in the 70
percent-complete survey. The remaining 30 percent of the survey has
now been processed resulting in 31 additional detections of stellar
coronae, all of which lie to the left of the dividing line.
Title: The Stellar Coronal Dividing Line
Authors: Haisch, B.; Schmitt, J. H. M. M.
Bibcode: 1992AAS...181.2308H
Altcode: 1992BAAS...24.1159H
No abstract at ADS
Title: Coordinated Ginga, IUE, and VLA Observations of Stellar
Activity in sigma 2 Coronae Borealis
Authors: Stern, R. A.; Uchida, Y.; Walter, F.; Vilhu, O.; Hannikainen,
D.; Brown, A.; Veale, A.; Haisch, B. M.
Bibcode: 1992ApJ...391..760S
Altcode:
Observations of the active cool star binary system Sigma(2) Corona
Borealis with the Large Area Counters on the Ginga X-ray satellite
over 2.5 d, or about two orbital periods, are reported. Throughout
the observations, Sigma(2) CrB exhibited X-ray variability on time
scales ranging from tens of minutes to hours. The X-ray light curve
shows evidence of flaring during the course of the observations. The
summed X-ray pulse height spectrum from flaring events compared
with similar spectra from quiescent periods indicates an increase in
coronal temperature. Periodogram analysis of the entire X-ray light
curve shows a possible periodicity at about 0.40-0.44 d, with no strong
signal at the orbital period or 1/2 of the orbital period. Coordinated
multiwavelength observations of IUE and the VLA indicate both UV and
microwave flaring during one X-ray outburst. The quiescent microwave
spectrum is not consistent with a thermal gyrosynchrotron process;
nonthermal gyrosynchrotron radiation is argued to be the most likely
emission process.
Title: IUE/ROSAT Observations of Proxim Centauri Flares
Authors: Haisch, Bernard
Bibcode: 1992iue..prop.4332H
Altcode:
No abstract at ADS
Title: Coronal Heating and the Dividing Line (With 2 Figures)
Authors: Haisch, B.
Bibcode: 1991mcch.conf..225H
Altcode:
No abstract at ADS
Title: Recent Advances in Extreme Ultraviolet Astronomy with
Multilayers
Authors: Haisch, B. M.; Whittemore, T. E.; Rottman, G. J.
Bibcode: 1991eua..coll..368H
Altcode:
No abstract at ADS
Title: Rotational modulation and flares on RS Canum Venaticorum and
BY Draconis-type stars. XV. Observations of Proxima Centauri and
solar calibration data.
Authors: Haisch, B. M.; Butler, C. J.; Foing, B.; Rodono, M.; Giampapa,
M. S.
Bibcode: 1990A&A...232..387H
Altcode:
Results are reported from simultaneous Exosat and IUE observations
of flaring in Proxima Cen on March 2, 1985. The data are presented in
extensive tables and sample spectra and discussed in detail. The peak
emission of the soft-X-ray flare is found to be about 3 x 10 to the 27th
erg/sec, with energy about 3 x 10 to the 30th erg and an associated
increase in Mg II flux to 17,000-67,000 erg/sq cm sec, or about an
order of magnitude lower than the solar value. The presence of flare-
and microflare-related processes heating the corona is inferred.
Title: Rotational modulation and flares on RS Canum Venaticorum and
BY Draconis-type stars. XIV. Phasen eclipse and flare observations
of YY Geminorum by EXOSAT and IUE.
Authors: Haisch, B. M.; Schmitt, J. H. M. M.; Rodono, M.; Gibson, D. M.
Bibcode: 1990A&A...230..419H
Altcode:
The eclipsing spectroscopic binary YY Geminorum has been observed
at optical, ultraviolet, and X-ray wavelengths for rotational
modulation, eclipse variability, and flaring. The epoch T(phi = 0) =
JD 2425698.3561, and the phase P = 0.81428224 d. The quiescent level
of Mg II emission is remarkably steady during the three-year observing
interval, with F(Mg II) roughly 3.6 x 10 to the -12th erg/sq cm/s. Both
stars appear to have identical Mg II surface fluxes, with F roughly
1.8 x 10 to the 6th erg/sq cm/s. Both stars appear to be covered
with evenly distributed Mg II emitting regions consistent with the
proposition of Doyle (1987) that saturation of the Mg II lines occurs
for stars having P less than 4 d, implying that such stars are entirely
covered by plage. The transition region lines show significantly more
rotational modulation and/or secular variability than Mg II. Both Mg II
and the transition region lines show preflare and postflare enhancement.
Title: Co-Ordinated GINGA IUE and VLA Observations of Flaring Activity
in SIGMA-2 CRB
Authors: Stern, R. A.; Haisch, B. M.; Uchida, Y.; Walter, F.; Veale,
A.; Brown, A.; Vilhu, O.; Hannikainen, D.
Bibcode: 1990ASPC....9..227S
Altcode: 1990csss....6..227S
The RS CVn system sigma-squared CrB was observed by the Ginga
X-ray satellite for a period of 2.5 days, or approximately 2 binary
orbits. Sigma-squared CrB exhibited almost continuous X-ray variability
on time scales ranging from minutes to days, including several
'flare-like' episodes with increased coronal temperature. The average
count rate was 4.2 +/- 1.2 cts/s (1.7-11.0 keV) corresponding to L(x)
of about 10 to the 29.6th erg/s (2-10 keV). Coordinated observations
with IUE and the VLA indicate microwave and ultraviolet flaring
associated with one X-ray flare.
Title: The X-Ray Emission of Late Type Evolved Stars
Authors: Maggio, A.; Vaiana, G. S.; Haisch, B. M.; Stern, R. A.;
Harnden, F. R., Jr.; Rosner, R.
Bibcode: 1990ixra.conf..233M
Altcode:
No abstract at ADS
Title: Einstein Observatory Magnitude-limited X-Ray Survey of
Late-Type Giant and Supergiant Stars
Authors: Maggio, A.; Vaiana, G. S.; Haisch, B. M.; Stern, R. A.;
Bookbinder, J.; Harnden, F. R., Jr.; Rosner, R.
Bibcode: 1990ApJ...348..253M
Altcode:
Results are presented of an extensive X-ray survey of 380 giant and
supergiant stars of spectral types from F to M, carried out with
the Einstein Observatory. It was found that the observed F giants
or subgiants (slightly evolved stars with a mass M less than about 2
solar masses) are X-ray emitters at the same level of main-sequence
stars of similar spectral type. The G giants show a range of emissions
more than 3 orders of magnitude wide; some single G giants exist with
X-ray luminosities comparable to RS CVn systems, while some nearby
large G giants have upper limits on the X-ray emission below typical
solar values. The K giants have an observed X-ray emission level
significantly lower than F and F giants. None of the 29 M giants were
detected, except for one spectroscopic binary.
Title: GINGA Observations of a Long Duration X-Ray Flare in the
Algol System
Authors: Stern, R. A.; Haisch, B. M.; Nagase, F.; Uchida, Y.;
Tsuneta, S.
Bibcode: 1990ASPC....9..224S
Altcode: 1990csss....6..224S
Algol was observed by the Ginga X-ray satellite for about 2 days in
January 1989, including both the primary and most of the secondary
optical eclipses. No evidence for X-ray eclipses was seen. A large
flare lasting over 12 h was detected prior to and during secondary
eclipse. The flare began with a peak temperature of about 69 MK,
gradually decaying to about 36 MK. Variable Fe line emission at 6.7
keV ws observed. The Fe line equivalent width is in clear disagreement
with theoretical predictions for an optically thin plasma.
Title: Ginga Observations of a Long-Duration X-ray Flare in Algol
Authors: Stern, R. A.; Haisch, B. M.; Nagase, F.; Uchida, Y.;
Tsuneta, S.
Bibcode: 1989BAAS...21.1205S
Altcode:
No abstract at ADS
Title: A relation between Balmer and soft X-ray emission in flares
Authors: Haisch, B. M.
Bibcode: 1989A&A...219..317H
Altcode:
Data are presented on 370 solar flares simultaneously observed and
classified in H-alpha and in the GOES (1-8 A) soft X-ray band. SMM
observations corroborate the association of the GOES and the H-alpha
events in all cases. These flares are used to examine the correlation
proposed recently by Butler, Rodono and Foing (1988).
Title: Simultaneous multi-wavelength observations of an intense
flare on AD Leonis.
Authors: Rodono', M.; Houdebine, E. R.; Catalano, S.; Foing, B.;
Butler, C. J.; Scaltriti, F.; Cutispoto, G.; Gary, D. E.; Gibson,
D. M.; Haisch, B. M.
Bibcode: 1989sasf.confP..53R
Altcode: 1989IAUCo.104P..53R; 1988sasf.conf...53R
The authors report on the first successful coordinated observations
of stellar flares carried out on March 28, 1984 simultaneously over
a wide range of wavelengths, from UV to microwaves, using the IUE
satellite, three ESO telescopes at La Silla (Chile) and the VLA at
Socorro (NM, USA).
Title: Solar and stellar flares
Authors: Haisch, B. M.; Rodono, M.
Bibcode: 1989SoPh..121.....H
Altcode: 1989IAUCo.104.....H
Various papers on solar physics are presented. Individual topics
addressed include: electron beam as origin of white-light solar flares,
solar flare diagnostic, multiwavelength observations of stellar flares,
impulsive phase of solar flares, electron acceleration in solar
flares, models of flaring loops, stellar flare spectral diagnostics,
preflare activity, radio emission from stellar flares, mass motions
associated with solar flares, importance of solar white-light flares,
hydrodynamic models of solar and stellar flares, long-duration solar
and stellar flares, magnetic equilibria and instabilities, stellar
flare statistics, role of eruption in solar flares, gradual phase
in solar flares, polarimetry of stellar active regions and flares,
particle acceleration in solar flares, and cyclotron lines in the
spectra of solar flares and solar active regions.
Title: The X-ray Emission of Late-Type Giant and Supergiant Stars:
Results of the Einstein Observatory Magnitude-Limited X-ray Survey
Authors: Maggio, A.; Vaiana, G. S.; Haisch, B. M.; Stern, R. A.;
Harnden, F. R.; Rosner, R.
Bibcode: 1988feta.conf...12M
Altcode:
No abstract at ADS
Title: EUV and XUV Observations of the Solar Corona made in
Conjunction with the Total Solar Eclipse of 1988 March 17/18
Authors: Rottman, G. J.; Hassler, D. M.; Jones, M. D.; Orrall, F. Q.;
Haisch, B. M.; Whittemore, T. E.
Bibcode: 1988BAAS...20..703R
Altcode:
No abstract at ADS
Title: Soft X-ray images of the solar corona using normal incidence
optics.
Authors: Bruner, M. E.; Haisch, B. M.; Brown, W. A.; Acton, L. W.;
Underwood, J. H.
Bibcode: 1988JPhys..49..115B
Altcode: 1988IAUCo.102..115B
A solar coronal loop system has been photographed in soft X-rays using
a normal incidence telescope based on multilayer mirror technology. The
image was recorded during a rocket flight on 1985 October 25, and was
dominated by emission lines arising from the Si XII spectrum. The
rocket also carried a high resolution soft X-ray spectrograph that
confirmed the presence of Si XII line radiation in the source.
Title: A multilayer X-ray mirror for solar photometric imaging flown
on a sounding rocket.
Authors: Haisch, B. M.; Whittemore, T. E.; Joki, E. G.; Brookover,
W. J.; Rottman, G. J.
Bibcode: 1988SPIE..982...38H
Altcode: 1988xia..conf...38H
The authors discuss the flight of a multilayer-coated mirror on a
sounding rocket experiment on March 17, 1988, which was used to obtain
photometric images of the Sun just prior to solar eclipse. Eight
full-disk images of the Sun were obtained by this XUV imager. The
images are of excellent quality and are being anlyzed together with
coordinated ground-based, eclipse coronagraph observations and radio
maps taken at the VLA and Greenbank.
Title: Coordinated Multiband Space and Groundbased Observations of
Surface Structures and Flares on Late Type Stars
Authors: Foing, B.; Butler, C. J.; Haisch, B. M.; Linsky, J. L.;
Rodono, M.
Bibcode: 1988copa.conf..197F
Altcode:
The authors discuss the need to coordinate future synoptic observations
at all accessible wavelengths for these objects which are highly
variable on all timescales from seconds to years.
Title: X-Ray Photographs of a Solar Active Region with a Multilayer
Telescope at Normal Incidence
Authors: Underwood, J. H.; Bruner, M. E.; Haisch, B. M.; Brown, W. A.;
Acton, L. W.
Bibcode: 1987Sci...238...61U
Altcode:
An astronomical photograph was obtained with a multilayer x-ray
telescope. A 4-centimeter tungsten-carbon multilayer mirror was flown
as part of an experimental solar rocket payload, and successful
images were taken of the sun at normal incidence at a wavelength
of 44 angstroms. Coronal Si-XII emission from an active region was
recorded on film; as expected, the structure is very similar to that
observed at O-VIII wavelengths by the Solar Maximum Mission flat crystal
spectrometer at the same time. The small, simple optical system used
in this experiment appears to have achieved a resolution of 5 to 10
arc seconds.
Title: Rotational modulation and flares on RS CVn and BY Dra-type
stars. V. EXOSAT and IUE observations of a flare on EQ Pegasi.
Authors: Haisch, B. M.; Butler, C. J.; Doyle, J. G.; Rodono, M.
Bibcode: 1987A&A...181...96H
Altcode:
Time-trailed UV spectra and a soft X-ray lightcurve were obtained
during a flare on the binary dMe star EQ Peg AB. On the basis of solar
flare Mg II surface fluxes and an about 70-percent enhancement in
the disk-integrated flux during the flare on EQ Peg, it is estimated
that the chromospheric flare covered about 1.5 percent of the stellar
surface. The size scale is estimated to be comparable to that of a solar
two-ribbon flare. This unusual flare is noted to exhibit a low-energy
soft X-ray rise phase which is longer than that of most flares; it
is longer than the decay phase and peaks much later than the medium
energy light curve. Evidence of variable Fe II emission and variable
continuum emission in select UV bands during the flare is noted.
Title: Very high resolution UV and X-ray spectroscopy and imagery
of solar active regions
Authors: Bruner, M.; Brown, W. A.; Haisch, B. M.
Bibcode: 1987lock.rept.....B
Altcode:
A scientific investigation of the physics of the solar atmosphere,
which uses the techniques of high resolution soft X-ray spectroscopy
and high resolution UV imagery, is described. The experiments were
conducted during a series of three sounding rocket flights. All three
flights yielded excellent images in the UV range, showing unprecedented
spatial resolution. The second flight recorded the X-ray spectrum of a
solar flare, and the third that of an active region. A normal incidence
multi-layer mirror was used during the third flight to make the first
astronomical X-ray observations using this new technique.
Title: Simultaneous X-ray and optical monitoring of the flare star
YZ CMi.
Authors: Doyle, J. G.; Butler, C. J.; Haisch, B. M.; Rodono, M.
Bibcode: 1986MNRAS.223P...1D
Altcode:
Broad-band photometric observations of YZ CMi show a 1.2 mag U-band
flare, however, simultaneous X-ray observations from EXOSAT show no
detectable increase. It is suggested that the event could have occurred
low down in a part of the chromosphere, which may not have been coupled
to the transition region and corona via magnetic fields. However,
a more plausible explanation may have been absorption of the X-rays
by an over-lying dense prominence. Several short-lived enhancements
(micro-flares) were detected in both the Johnson U-band and the Balmer
emission lines.
Title: Variability in Active Region Coronal Loops
Authors: Haisch, B. M.
Bibcode: 1986BAAS...18Q.901H
Altcode:
No abstract at ADS
Title: The Local Distribution of Interstellar Matter Derived from
(B-V) Colors of Bright Stars
Authors: Davidson, G. T.; Claflin, E. S.; Haisch, B. M.
Bibcode: 1986BAAS...18.1036D
Altcode:
No abstract at ADS
Title: On the Dividing Line for Stellar Coronae
Authors: Antiochos, S. K.; Haisch, B. M.; Stern, R. A.
Bibcode: 1986ApJ...307L..55A
Altcode:
The authors describe a possible explanation for the observation that
late-type stars falling in a certain region of the H-R diagram exhibit
no X-ray emission and, hence, appear not to have coronae. The basic
idea of the authors' model is that due to the low surface gravity
that characterizes the stars without X-ray emission, a hot (T >
106K) corona is thermally unstable and spontaneously
cools down to chromospheric temperatures. The key parameter that
determines the outer atmospheric structure is shown to be the ratio
of the gravitational scale height of plasma at T = 105K to
the maximum height of closed magnetic field lines in the corona.
Title: Coordinated Exosat and spectroscopic observations of flare
stars and coronal heating
Authors: Butler, C. J.; Rodono, M.; Foing, B. H.; Haisch, B. M.
Bibcode: 1986Natur.321..679B
Altcode:
The X-ray flux of dMe stars is thought to arise from two distinct
mechanisms, one involving a continuous `quiescent' emission from a
high-temperature plasma and the other involving the dramatic flare
events which have long been known to occur on these stars. We present
here some results of simultaneous monitoring of the two flare stars, UV
Ceti and EQ Peg, with Exosat and ground-based optical spectroscopy. We
observe short-timescale variability in the 0.1-2-keV emission from both
these objects and, in the case of UV Ceti, find a strong correlation
between the soft X-ray and Hγ fluctuations. The implication is that
much of the low-level X-ray flux previously considered `quiescent'
probably originates from small flare events.
Title: Non-Potential Features Observed in the Magnetic Field of an
Active Region
Authors: Gary, G. A.; Moore, R. L.; Hagyard, M. J.; Haisch, B. M.
Bibcode: 1986BAAS...18..709G
Altcode:
No abstract at ADS
Title: Coronae on Stars
Authors: Haisch, B. M.
Bibcode: 1986IrAJ...17..200H
Altcode:
Three lines of evidence are noted to point to a flare heating source for
stellar coronae: a strong correlation between time-averaged flare energy
release and coronal X-ray luminosity, the high temperature flare-like
component of the spectral signature of coronal X-ray emission, and the
observed short time scale variability that indicates continuous flare
activity. It is presently suggested that flares may represent only
the extreme high energy tail of a continuous distribution of coronal
energy release events.
Title: Coordinated IUE and ground-based observations of stellar
flares: YZ CMi, Proxima Cen and AD Leo.
Authors: Foing, B. H.; Rodono, M.; Cutispoto, G.; Catalano, S.; Linsky,
J. L.; Gibson, D. M.; Brown, A.; Haisch, B. M.; Butler, C. J.; Byrne,
P. B.; Andrews, A. D.; Doyle, J. G.; Gary, D. E.; Henry, G. W.; Russo,
G.; Vittone, A.; Scaltriti, F.
Bibcode: 1986RMxAA..12..213F
Altcode:
Coordinated observations of stellar flares were obtained with lUE
and several ground-based facilities in March 1984.The simultaneous
observations allowed it to cover a wide range of wavelengths from ii5nm
to 6cm.We intend to study the effect ofthe observed flares at different
atmospheric heights in order to estimate the energy budget,the time
scales and the cooling processes.Our observations includetime-resolved
IUE spectroscopy at SWP(115-195nm) and LWP(190-320nm),optical
spectroscopy at the ESO 3.6m+IDS (355-440nm),high resolution
spectroscopy at the ESO 1.4m CAT+CES(653-659nm),narrow band H alpha
and wide band optical photometry, infrared photometry at 2.2microns
and microwave observations at 2,6 and 20 cm We present for some
flare events,among the results,the first detection of infrared flux
decrease -or "negative flare"-in coincidence with the flux increase
at the other wavelengths:the broadening and changes of the Balmer H
lines,He and high excitation lines;the appearance of higher members
of the Balmer serie;the enhancements of Mg II doublet and Fe II blend
(260nm);and the flare detection at 2cm and 6cm
Title: A Comparison of Photospheric Electric Current and Ultraviolet
and X-Ray Emission in a Solar Active Region
Authors: Haisch, B. M.; Bruner, M. E.; Hagyard, M. J.; Bonnet, R. M.
Bibcode: 1986ApJ...300..428H
Altcode:
This paper presents an extensive set of coordinated observations
of a solar active region, taking into account spectroheliograms
obtained with the aid of the Solar Maximum Mission (SMM) Ultraviolet
Spectrometer Polarimeter (UVSP) instrument, SMM soft X-ray polychromator
(XRP) raster maps, and high spatial resolution ultraviolet images of
the sun in Lyman-alpha and in the 1600 A continuum. These data span
together the upper solar atmosphere from the temperature minimum to
the corona. The data are compared to maps of the inferred photospheric
electric current derived from the Marshall Space Flight Center (MSFC)
vector magnetograph observations. Some empirical correlation is found
between regions of inferred electric current density and the brightest
features in the ultraviolet continuum and to a lesser extent those
seen in Lyman-alpha within an active region.
Title: Flares: the solar-stellar perspective and opportunities.
Authors: Haisch, B. M.
Bibcode: 1986RALR...85..224H
Altcode:
The author outlines eight specific areas in which fundamental concepts
of flare physics will almost certainly be tested and refined via
a solar-stellar approach. 1. Electron beam versus superthermal
heating of the lower flare atmosphere. 2. The chromospheric and
photospheric response: white-light flaring. 3. Microflaring and the
heating of coronae and the driving of winds. 4. Flare rates and power
spectra. 5. Mass motions. 6. Elemental abundance anomalies during
flares. 7. Periodicities: links to the interior structure of the Sun
and stars. 8. Flaring on other than dMe stars.
Title: X-Ray Resonance Scattering in a Spherically Symmetric
Coronal Model
Authors: Haisch, B. M.; Claflin, E. S.
Bibcode: 1985SoPh...99..101H
Altcode:
In the solar corona the opacities of some of the prominent X-ray
emission lines are on the order of τ ≈ 1 over typical coronal
path lengths. We present and discuss a particular solution of
the radiative transfer problem involving an extended, spherically
symmetric coronal shell radiating isotropic, homogeneous emission
in which single-scattering also takes place. Within the context of
this simplified model we find that scattered radiation is an important
contribution to the total emergent resonance line flux and that for the
He-like family of resonance (r), intercombination (i), and forbidden
(f) lines, the ratio G=(f + i)/r would decrease as a function of
optical depth for disk-center emission in an extended spherically
symmetric corona.
Title: IUE spectra of GO V-G5 V solar-type stars.
Authors: Haisch, B. M.; Basri, G.
Bibcode: 1985ApJS...58..179H
Altcode:
An atlas of IUE short-wavelength spectra for a set of 14 bright G0
V-G5 V stars are presented, and it is shown that these manifest a
range of qualitatively different chromospheric and transition region
spectra and significant differences in radiative flux originating at
the temperature minimum level. A comprehensive survey of observational
data and physical parameters of these stars has been performed, and
tabular summaries of the data are presented. It is concluded that
the UV continuum longward of about 1600 A is a diagnostic of the
temperature minimum. A considerable range of minimum temperature for
stars of similar effective temperature and spectral type is found. The
temperature minimum of the sun is highly structured on spatial scales
of about one arcsec.
Title: Peculiar emission lines in the spectrum of the flare star YZ
Canis Minoris.
Authors: Haisch, B. M.; Glampapa, M. S.
Bibcode: 1985PASP...97..340H
Altcode:
During a series of spectral scans in search of flares on the dMe
star YZ CMi the authors observed prominent chromospheric emission
lines of Hγ λ4340, Hδ λ4100, Ca II H λ3968 blended with Hɛ
λ3970, Ca II K λ3934, and Hζ λ3889. During one five-minute scan
the authors recorded the following peculiar transient phenomena:
(1) the appearance of an exceptionally strong line at ≡λ4007; (2)
the simultaneous appearance of another prominent feature at ≡λ4276;
and (3) a change in the ratio of (Ca II H+Hɛ)/Ca II K. The authors
discuss the possible origin of this unusual transient spectrum.
Title: An analysis of scattered light in low dispersion IUE spectra.
Authors: Basri, G.; Clarke, J. T.; Haisch, B. M.
Bibcode: 1985A&A...144..161B
Altcode:
A detailed numerical simulation of light scattering from the
low-resolution grating in the short wavelength spectrograph of the
IUE Observatory was developed, in order to quantitatively analyze the
effects of scattering on both continuum and line emission spectra. It
is found that: (1) the redistribution of light by grating scattering
did not appreciably alter either the shape or the absolute flux level
of continuum spectra for A-F stars; (2) late-type stellar continua
showed a tendency to flatten when observed in scattered light toward
the shorter wavelengths; and (3) the effect of grating scattering
on emission lines is to decrease measured line intensities by an
increasing percentage toward the shorter wavelengths. The spectra
obtained from scattering experiments for solar-type and late type
stars are reproduced in graphic form.
Title: Coordinated Multiband Observations of Stellar Flares
Authors: Rodono, M.; Foing, B. H.; Linsky, J. L.; Butler, J. C.;
Haisch, B. M.; Gary, D. E.; Gibson, D. M.
Bibcode: 1985Msngr..39....9R
Altcode:
The March 28, 1984 flare of AD Leo is characterized on the basis of
observations obtained over the spectral range from 200 nm to 20 cm using
the IUE, the VLA, and four ESO telescopes as part of a coordinated
multiband international campaign. The data are presented graphically
and discussed, with consideration of faint negative K-band events
observed simultaneously with the optical flare; an H-alpha precursor
with longer energy-release relaxation than in the U continuum; and
remarkably enhanced UV continuum, Mg II doublet, and 260-nm Fe II
blend during the last secondary optical peak.
Title: Soft X-ray polychromator for the Solar Maximum Mission
Authors: Haisch, B. M.; Levay, M.; Stern, R. A.; Strong, K. T.;
Wolfson, C. J.; Acton, L. W.
Bibcode: 1984lock.rept.....H
Altcode:
The XRP was designed to measure the following temporal and spatial
properties of the active and flaring Sun: electron temperature,
departures from steady state, ion kinetic temperatures, and electron
density. The Bent Crystal Spectrometer (BCS) is capable of measuring
the broadening and blue shifts often observed in the impulsive phase of
flares. The six simultaneous line fluxes indicative of six different
temperatures of formation observable by the Flat Crystal Spectrometer
(FCS) allows the derivation of the differential emission measure of
the plasma at each raster point. During the operational periods of the
XRP hundreds of flares of C-level (GOES classification) were observed
and brighter in both the FCS and BCS, including 5 X-flares. Associated
theoretical work in atomic physics, stimulated in part by the promise
of XRP measurements, has benefitted from the experimental data on
solar plasmas which the XRP has provided in abundance.
Title: X-ray, Ultraviolet, Optical and Magnetic Structure in and
near an Active Region
Authors: Haisch, B. M.; Tarbell, T. D.; Bruner, M. E.; Acton, L. W.;
Bonnet, R. M.; Hagyard, M. J.
Bibcode: 1984BAAS...16Q1002H
Altcode:
No abstract at ADS
Title: Coordinated IUE and ground-based observations of active stars:
flare events on YZ CMi, V1005 Ori, AD Leo and AR Lac.
Authors: Rodonò, M.; Cutispoto, G.; Catalano, S.; Linsky, J. L.;
Gibson, D. M.; Brown, A.; Haisch, B. M.; Butler, C. J.; Byrne, P. B.;
Andrews, A. D.; Doyle, J. G.; Gary, D. E.; Henry, G. W.; Russo, G.;
Vittone, A.; Scaltriti, F.; Foing, B.
Bibcode: 1984ESASP.218..247R
Altcode: 1984iue..conf..247R
Observations of stellar flares were obtained with IUE and ground-based
facilities simultaneously over a wide range of wavelengths in order
to study the effect of the flare radiation at different atmospheric
levels. Observations include time-resolved IUE and optical spectroscopy,
narrow and wide-band optical photometry, IR photometry, and microwave
observations. Results include detection of IR flux decrease, or negative
flare, in coincidence with flux increase at all other wavelengths.
Title: Normal incidence multilayer mirrors for extreme ultraviolet
astronomy.
Authors: Stern, R. A.; Haisch, B. M.; Joki, E. G.; Catura, R. C.
Bibcode: 1984SPIE..445..347S
Altcode:
Sputtered multilayer coatings allow the use of normal incidence optics
in the extreme ultraviolet (EUV) region below 500 Å. Multilayer
mirrors can be tailored to provide images at strong EUV lines in the
sun and stars, in many cases making more efficient use of the telescope
aperture than grazing incidence optics. Current efforts in the design,
fabrication, and testing of EUV multilayer mirrors are discussed.
Title: Creation of photometric star catalogs using UBV data and
model stellar atmospheres.
Authors: Haisch, B. M.; Johnson, H. M.; Davidson, G. T.
Bibcode: 1983JAnSc..31..473H
Altcode:
The creation of star catalogs for any sensor system is accomplished
with the use of observations in the UBV system in conjunction with
the theoretical predictions of stellar fluxes derived from models of
stellar atmospheres. A comparison of data on eight of the principal
photometric systems currently in use shows that the Johnson UBV system
and its extension clearly provides the most extensive data base, though
the uvby system is better suited for estimating the stellar parameters
of temperature, gravity, and abundance. The absolute calibration of
the UBV system is discussed in detail. It is shown that for distant
(reddened) stars, the spectral energy distribution function is affected
by wavelength-dependent scattering and absorption. New updated tables
for effective temperature, gravity, and (B - V) color are presented
for all normal MK-type stars. Also, tables and prescriptions are
given for identifying many special and peculiar types of stars by
equivalent MK-types.
Title: IUE Observations of a Peculiar Flare Event on the dM0. 5e
Star G1 182
Authors: Haisch, B. M.; Linsky, J. L.; Bornmann, P. L.; Rodono, M.
Bibcode: 1983BAAS...15..948H
Altcode:
No abstract at ADS
Title: Transport and Containment of Plasmas Particles and Energy
Within Flares
Authors: Acton, L. W.; Brown, W. A.; Bruner, M. E. C.; Haisch, B. M.;
Strong, K. T.
Bibcode: 1983SoPh...86...79A
Altcode:
Results from the analysis of flares observed by the Solar Maximum
Mission (SMM) and a recent rocket experiment are discussed. We
find evidence for primary energy release in the corona through the
interaction of magnetic structures, particle and plasma transport
into more than a single magnetic structure at the time of a flare
and a complex and changing magnetic topology during the course of a
flare. The rocket data are examined for constraints on flare cooling,
within the context of simple loop models. These results form a basis
for comments on the limitations of simple loop models for flares.
Title: Coordinated Einstein and IUE observations of a disparitions
brusques type flare event and quiescent emission from Proxima
Centauri.
Authors: Haisch, B. M.; Linsky, J. L.; Bornmann, P. L.; Stencel,
R. E.; Antiochos, S. K.; Golub, L.; Vaiana, G. S.
Bibcode: 1983ApJ...267..280H
Altcode:
The Einstein Imaging Particle Counter observed a major X-ray flare
in its entirety during a 5-hr period of simultaneous observations,
with the IUE, of the dM5e flare star Proxima Centauri in August,
1980. The detailed X-ray light curve, temperature determinations
during various intervals, and UV line fluxes obtained before, during,
and after the flare indirectly indicate a 'two-ribbon flare' prominence
eruption. The calculated ratio of coronal to bolometric luminosity for
the event is about 100 times the solar ratio. The Proxima Cen corona
is analyzed in the context of static loop models, in light of which
it is concluded that less than 6% of the stellar surface seems to be
covered by X-ray emitting active regions.
Title: Coordinated Ultraviolet, Optical and Radio Observations of
RS CVn and Flare Stars
Authors: Byrne, P. B.; Butler, C. J.; Andrews, A. D.; Rodono, M.;
Catalano, S.; Pazzani, V.; Linsky, J. L.; Bornman, P.; Haisch, B. M.
Bibcode: 1983IBVS.2258....1B
Altcode:
No abstract at ADS
Title: X-ray observations of stellar flares
Authors: Haisch, B. M.
Bibcode: 1983ASSL..102..255H
Altcode: 1983ards.proc..255H; 1983IAUCo..71..255H
The history of stellar X-ray flare observations prior to the Einstein
Observatory is reviewed. X-ray light curves as measured by the IPC
are then presented for all time resolved flare events discovered as
of July 1982 in the Einstein data set. These light curves are analyzed
in terms of solar-like loop models to derive densities, temperatures,
loop lengths, magnetic field strength lower limits, etc. The failure
of the model to adequately represent the observations in the case
of the YZ CMi flares is discussed. The relationship of X-ray to
optical emission, and X-ray to UV emission, is considered from both
an observational and a theoretical viewpoint. It is concluded that
the characterization of a flare by a single, time-averaged ratio,
L(x)/L(opt), is not physically significant.
Title: Identification of Active Regions on the Eclipsing Binary
Flare Star Pair YY Gem
Authors: Haisch, B. M.
Bibcode: 1983iue..prop.1449H
Altcode:
The eclipsing spectroscopic binary TY Cam is unique sand extremely
interesting because both stars are identical dMle flare-active
stars in a circular, short period (19.6 hr) orbit. Both stars are
synchronously rotating; extended starspot regions, plage regions and
regions of flare activity have previously been identified and napped
out. Both stars are bright X-ray and 6 cm radio sources. We propose
to Investigate the geometrical distribution of active regions on the
stellar surfaces by taking a series of long and short wavelength IUE
low dispersion spectra covering about 50% of just over three orbital
periods; we will especially concentrate on taking spectra during
tines of eclipse. In addition, the chromospheric and transition
region fluxes will be compared to other dM and dMe stars to further
toot the rotation-activity connection. Differential emission measure
analysis will be used to compare active region properties to solar
plage emission and to loop models. Intercomparisons will be made to
photospheric variability (from simultaneous ground-based photometry
and spectrophotometry) and to coronal variability (from simultaneous
VLA observations of 6 cm gyroresonance emission).
Title: Further observational evidence for a coronal boundary line
in the cool star region of the H-R diagram.
Authors: Haisch, B. M.; Simon, T.
Bibcode: 1982ApJ...263..252H
Altcode:
Soft X-ray emission was detected from Gamma Hya and 37 Com, at
levels of 6-8 x 10 to the -13th ergs/sq cm per sec, during 0.2-4.0
keV observations of eight G-K giant stars obtained with the Einstein
Observatory's Imaging Proportional Counter. Upper limits of about 3
x 10 to the 13th ergs/sq cm per sec were determined for the remaining
stars. These results are judged to strengthen the Ayres et al (1981)
findings that stellar coronae whose temperature is greater than one
million K are either very weak or entirely absent among red giants and
supergiants, while a large range in coronal emission exists among the
yellow giant and supergiant stars.
Title: Implications of Solar Flare Observations on Stellar X-Ray
Flares
Authors: Antiochos, S. K.; Haisch, B. M.; Stern, R. A.
Bibcode: 1982BAAS...14..864A
Altcode:
No abstract at ADS
Title: Simultaneous X-ray, ultraviolet, optical, and radio
observations of the flare star Proxima Centauri
Authors: Haisch, B. M.; Slee, O. B.; Siegman, B. C.; Nikoloff, I.;
Candy, M.; Harwood, D.; Verveer, A.; Quinn, P. J.; Wilson, I.; Linsky,
J. L.
Bibcode: 1981ApJ...245.1009H
Altcode:
Results of coordinated program of observations in the X-ray, UV,
optical and radio regions of the dM5e flare star Proxima Centauri
are presented. Simultaneous observations of the star were obtained
on March 6 and March 7, 1979, by the Einstein Observatory IPC, the
IUE SWP and LWR cameras at low dispersion, three ground-based optical
telescopes in Australia and the Parkes 64-m radio telescope. A total
of 10 radio bursts and six optical flares was detected during three
nights of simultaneous radio and optical observations, which appear
to be broadly correlated. A major X-ray flare event was detected with
temperatures of 1.7 x 10 to the 7th and 1.2 x 10 to the 7th K during
the rise and decay phases, respectively, respective X-ray fluxes of
3.0 x 10 to the -11th and 3.7 x 10 to the -11th ergs/sq cm per sec,
and changes in spectral flux distribution. No radio, optical or UV flare
emission corresponding to the X-ray flare was detected. The X-ray flare
is interpreted in terms of an arch model with cooling predominantly by
X-ray radiation, with an electron density of 1.0 x 10 to the 11th/cu
cm during the decay phase and a total arch length comparable to the
size of the star itself. The X-ray flare observed is thus more similar
to a typical strong solar flare than heretofore seen on a flare star.
Title: Results from an extensive Einstein stellar survey.
Authors: Vaiana, G. S.; Cassinelli, J. P.; Fabbiano, G.; Giacconi,
R.; Golub, L.; Gorenstein, P.; Haisch, B. M.; Harnden, F. R., Jr.;
Johnson, H. M.; Linsky, J. L.; Maxson, C. W.; Mewe, R.; Rosner, R.;
Seward, F.; Topka, K.; Zwaan, C.
Bibcode: 1981ApJ...245..163V
Altcode:
The preliminary results of the Einstein Observatory stellar X-ray survey
are presented. To date, 143 soft X-ray sources have been identified with
stellar counterparts, leaving no doubt that stars in general constitute
a pervasive class of low-luminosity galactic X-ray sources. Stars along
the entire main sequence, of all luminosity classes, pre-main sequence
stars as well as very evolved stars have been detected. Early type
OB stars have X-ray luminosities in the range 10 to the 31st to 10 to
the 34th ergs/s; late type stars show a somewhat lower range of X-ray
emission levels, from 10 to the 26th to 10 to the 31st ergs/s. Late type
main-sequence stars show little dependence of X-ray emission levels upon
stellar effective temperature; similarly, the observations suggest weak,
if any, dependence of X-ray luminosity upon effective gravity. Instead,
the data show a broad range of emission levels (about three orders of
magnitude) throughout the main sequence later than F0.
Title: The Status of the Corona/Wind Boundary Line in the Cool Star
Region of the HR Diagram
Authors: Haisch, B. M.; Simon, T.
Bibcode: 1981BAAS...13Q.784H
Altcode:
No abstract at ADS
Title: The Corona and Chromosphere of Proxima Centauri during Flare
and Quiescent Times
Authors: Haisch, B. M.; Linsky, J. L.; Slee, O. B.
Bibcode: 1981BAAS...13..515H
Altcode:
No abstract at ADS
Title: Solar Type Stars
Authors: Haisch, Bernard
Bibcode: 1981iue..prop..877H
Altcode:
No abstract at ADS
Title: Einstein X-ray observations of Proxima Centauri and the
surrounding region
Authors: Haisch, B. M.; Harnden, F. R., Jr.; Seward, F. D.; Vaiana,
G. S.; Linsky, J. L.; Rosner, R.
Bibcode: 1980ApJ...242L..99H
Altcode:
The first detection of both quiescent and flaring soft X-ray emission
from a dMe flare star, Proxima Centauri (dM5e) is reported. The data
are analyzed for temporal variability and spectral characteristics. The
quiescent state is characterized by a mean X-ray luminosity of 1.5 x 10
to the 27th erg s/s, corresponding to a mean surface flux of 700,000
erg s/sq cm-s, and an inferred temperature of 4-million K. The flare
that is detected has a peak flux of 7.4 x 10 to the 27th erg s/s and
a peak temperature of 17-million K. The implications of these data for
models of the quiescent and flare coronae of dMe stars are discussed.
Title: A practical introduction to astrometry.
Authors: Haisch, B. M.
Bibcode: 1980JAnSc..28..205H
Altcode:
This paper serves as a practical review of astrometry for the
non-specialist. It presents a step-by-step guide to the origin of
various precession, nutation and aberration terms and the application
of those terms to astrometrical data. Detailed examples are worked
out applying the formalism to sample calculations of mean, true and
apparent positions. Also included is a brief discussion of the new
(1976) set of constants which will replace the present system when the
new fundamental astrometrical reference system, the FK5, is introduced.
Title: Observations of the quiescent corona, transition region,
and chromosphere in the dMe flare star Proxima Centauri.
Authors: Haisch, B. M.; Linsky, J. L.
Bibcode: 1980ApJ...236L..33H
Altcode:
No abstract at ADS
Title: Outer atmospheres of cool stars. IV. A discussion of cool
stellar wind models.
Authors: Haisch, B. M.; Linsky, J. L.; Basri, G. S.
Bibcode: 1980ApJ...235..519H
Altcode:
Possible wind models for late-type stars which appear not to have hot
coronae and transition regions are investigated; taking Arcturus and
the prototypical star, models with T less than approximately 20,000
K are considered, and solutions with mass loss rates of 10 to the
-9th solar masses per year are sought. The radiation pressure of
L-alpha resonance scattering can exceed the force of gravity in
the chromosphere and initiate a net outflow, but is insufficient
to sustain a wind, except perhaps in the presence of an additional
momentum input term such as Alfven wave pressure. It is concluded that
L-alpha radiation-pressure-initiated winds can occur in stars to the
right of the Linsky-Haisch dividing line in the H-R diagram between
stars with and without transition regions and presumably hot coronae,
and that the existence of these winds may explain energetically the
absence of hot coronae in these stars.
Title: The 2300-3000A IUE Spectrum of Alpha Orionis
Authors: Haisch, B. M.; van der Hucht, K. A.; Linsky, J. L.
Bibcode: 1979BAAS...11..681H
Altcode:
No abstract at ADS
Title: HEAO 1 observations of X-ray emission from flares in dMe stars.
Authors: Kahn, S. M.; Linsky, J. L.; Mason, K. O.; Haisch, B. M.;
Bowyer, C. S.; White, N. E.; Pravdo, S. H.
Bibcode: 1979ApJ...234L.107K
Altcode:
The paper reports the detection of two X-ray flares from each of the
nearby dMe stars, AT Mic and AD Leo, with the A-2 experiment on board
HEAO 1. A spectrum obtained during the brighter AT Mic flare, the
first X-ray spectrum of a stellar flare, is well matched by a thermal
model with a temperature 3 x 10 to the 7 K and an iron K-alpha emission
line. The X-ray luminosities derived are in the range 1.3-16 x 10 to
the 30th ergs/s, while emission measures are in the range 1.1-14 x 10
to the 53rd/cu cm. The estimated Lx/Lopt ratios exceed unity and are
inconsistent with Mullan's flare model. Several scenarios to explain
this discrepancy are proposed.
Title: A comparison of emission lines in the ultraviolet spectra
of alpha Boo (K2 IIIp), alpha Tau (K5 III), alpha Ori (M1-2 Ia-b)
and alpha Sco (M1.5 Iab+B2.5 V).
Authors: van der Hucht, K. A.; Stencel, R. E.; Haisch, B. M.; Kondo, Y.
Bibcode: 1979A&AS...36..377V
Altcode:
Observations and identifications are presented of 45 emission lines in
the near-ultraviolet spectra of Boo (K2 IIIp), x Tau (KS III), z Ori
(M1-2 Ia-b) and 1 +2 Sco (M1.5 Iab+ B2.5 V). The useful wavelength
ranges, A for Boo, 28( A for Tau, A for Ori and 2()()( 2400 A, 27O(
3200 A for 1+2 Sco are covered with a resolution of 0.1 A. We have
identified emission lines of Mg I, Fe I, Fe II, Fe III and a possible
Si I emission line, in addition to the strong chromospheric Mg II h
and k resonance emission lines. Several Fe I and Fe II fluorescence
emission lines are identified, which may originate through pumping by
the Mg II X2795 k line. Because of the lack of an intensity calibration
only a qualitative description of the data is possible. Where possible
we have established radial velocities for the various regions in the
chromospheres and circumstellar envelopes of the stars. The emission
lines of x Ori show an outflow of material from both the chromospheric
and circumstellar regions, in contrast to a previously determined
inflow as measured by Boesgaard and Magnan (1975). We conclude
that we are seeing a different phase of an apparently variable mass
motion phenomenon. We suggest an interpretation in terms of very large
convective elements as hypothesized by Schwarzschild (1975). The other
three stars show a blue shifted absorption component in the Mg II lines
on top of the overall redshifted emission. The Fe III emission lines in
the spectrum of 1 +2 Sco are due to the presence of the B star within
the circumstellar envelope of the M star. Key words: chromosphere -
circumstellar envelope - stars: individual - spectra: ultraviolet
Title: IUE and the Search for a Lukewarm Corona
Authors: Pasachoff, J. M.; Linsky, J. L.; Haisch, B. M.; Boggess, A.
Bibcode: 1979S&T....57..438P
Altcode:
The use of the International Ultraviolet Explorer (IUE) to search
for stars having neither a hot corona nor a cool outer atmosphere,
but a lukewarm corona is outlined. An interactive computer system
permits extensive analysis of the data immediately after transmission
to earth, allowing the results of one exposure to influence the taking
of subsequent exposures. The observation program is illustrated for the
star HR 1099, noting that observations were taken while previous spectra
were being analyzed. Observations of many stars of spectral types G and
K lead to the construction of a border region on the Hertzsprung-Russell
diagram between stars with hot coronas and those with cool outer
atmospheres. Stars lying near this border region were then observed;
however, none with lukewarm coronas was found. The interactive control
facility in the satellite control room is considered an important
factor in the efficient implementation of the search procedure.
Title: Outer atmospheres of cool stars. I. The sharp division into
solar-type and non-solar-type stars.
Authors: Linsky, J. L.; Haisch, B. M.
Bibcode: 1979ApJ...229L..27L
Altcode:
No abstract at ADS
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.
Bibcode: 1979BAAS...11..471H
Altcode:
No abstract at ADS
Title: Radiative transfer in spherical dust shells using a generalized
two-stream Eddington approximation.
Authors: Haisch, B. M.
Bibcode: 1979A&A....72..161H
Altcode:
Application of a generalized two-stream Eddington approximation to
the problem of radiative transfer in extended, spherically symmetric
dust shells is presented. It is assumed that the radiation field can
be characterized by the mean intensity, the flux, and a positionally
dependent direction cosine specifying the division into two solid-angle
ranges. The direction cosine is not specified a priori and is a
function of the geometry, opacity, and emissivity in the dust shell. A
multiple-grain-size multiple-temperature-distribution dust shell is
postulated in which isotropic and anisotropic scattering as well as
absorption and thermal reemission are allowed. A program has been
developed that solves for the multiple temperature distributions by
applying the constraint of radiative equilibrium to each grain size,
and then calculates emergent fluxes. Results of one such calculation
are presented for a model dust shell having a maximum optical depth
(approximately 41) in the visible, clearly showing large optical
extinction and a moderate infrared excess.
Title: Lyman alpha initiated winds in late-type stars
Authors: Haisch, B. M.; Linsky, J. L.; van der Hucht, K. A.
Bibcode: 1979IUE1.symp..383H
Altcode: 1979STIN...8016008H
One of the first major results of the IUE survey of late-type stars
was the discovery of a sharp division in the HR diagram between stars
with solar type spectra (chromosphere and transition region lines) and
those with non-solar type spectra (only chromosphere lines). This result
is especially interesting in view of observational evidence for mass
loss from G and K giants and super-giants discussed recently by both
Reimers and Stencel. In the present paper models of both hot coronae
and cool wind flows are calculated using stellar model chromospheres as
starting points for stellar wind calculations in order to investigate
the possibility of having a 'supersonic transition locus' in the HR
diagram dividing hot coronae from cool winds. It is concluded from
these models that the Lyman-alpha flux may play an important role
in determining the location of a stellar wind critical point. The
interaction of Lyman-alpha radiation pressure with Alfven waves in
producing strong, low temperature stellar winds in the star Arcturus
is investigated.
Title: A coordinated X-ray, optical, and microwave study of the
flare star Proxima Centauri.
Authors: Haisch, B. M.; Linsky, J. L.; Slee, O. B.; Hearn, D. R.;
Walker, A. R.; Rydgren, A. E.; Nicolson, G. D.
Bibcode: 1978ApJ...225L..35H
Altcode:
Results are reported for a three-day coordinated observing program
to monitor the flare star Proxima Centauri in the X-ray, optical, and
radio spectrum. During this interval 30 optical flares and 12 possible
radio bursts were observed. The SAS 3 X-ray satellite made no X-ray
detections. An upper limit of 0.08 on the X-ray/optical luminosity ratio
is derived for the brightest optical flare. The most sensitive of the
radio telescopes failed to detect 6-cm emission during one major and
three minor optical flares, and on this basis an upper limit on the
flare radio emission (1 hundred-thousandth of the optimal luminosity)
is derived.
Title: Outer Atmospheres of Cool Stars: The Sharp Division into
Solar-Type and Alpha Orionis-Type Stars
Authors: Linsky, J. L.; Haisch, B. M.
Bibcode: 1978BAAS...10..647L
Altcode:
No abstract at ADS
Title: IUE and BUSS Observations of Alpha Orionis
Authors: Haisch, B. M.; Linsky, J. L.; van der Hucht, K. A.
Bibcode: 1978BAAS...10..646H
Altcode:
No abstract at ADS
Title: Analysis of the chromospheric spectrum of O I in Arcturus.
Authors: Haisch, B. M.; Linsky, J. L.; Weinstein, A.; Shine, R. A.
Bibcode: 1977ApJ...214..785H
Altcode:
The ultraviolet and near-infrared spectra of O I in Arcturus are
analyzed by a 15-level 14-transition model for O I and the Ayres-Linsky
(1975) model chromosphere. It is found that the anomalously bright O
I resonance lines at 1302, 1305, and 1306 A can be readily explained
by a Ly-beta-pumped fluorescence mechanism as originally proposed by
Bowen (1974). Observed equivalent widths of the near-infrared triplet
and singlet lines are also consistent with the model predictions,
but the intercombination lines at 1355 and 1359 A and near-infrared
quintet lines may pose a problem.
Title: Extreme-ultraviolet observations of flare on Proxima Centauri
and implications concerning flare-star scaling theory.
Authors: Haisch, B. M.; Linsky, J. L.; Lampton, M.; Paresce, F.;
Margon, B.; Stern, R.
Bibcode: 1977ApJ...213L.119H
Altcode:
No abstract at ADS
Title: Extreme Ultraviolet Observations of a Flare on Proxima Centauri
and Implications Concerning Flare Star Scaling Theory.
Authors: Haisch, B. M.; Linsky, J. L.; Bowyer, S.
Bibcode: 1976BAAS....8..545H
Altcode:
No abstract at ADS
Title: Theoretical wavelength dependence of polarization in early-type
stars.
Authors: Haisch, B. M.; Cassinelli, J. P.
Bibcode: 1976ApJ...208..253H
Altcode:
The wavelength dependence of linear polarization produced by
electron scattering and modified by an absorptive opacity in the
extended, distorted atmospheres of early-type stars is examined
theoretically. When we use an iterative scheme, the equation of
radiative transfer for plane polarized light is solved numerically
for four model atmospheres representing a Wolf-Rayet star and three
types of Be star. The extended, but heretofore spherically symmetric,
atmosphere models are now assumed to have the shapes of either a
rigidly rotating star (called a Roche model) or a truncated disk. The
asymmetry provides polarization in the net observable flux. The amount
of this polarization and its wavelength dependence are investigated
and compared to observations. It is found that only a highly flattened
disk can provide polarization in excess of 1 percent as is sometimes
observed. The wavelength dependence of the models agrees with the
observed shape of the polarization curve between the Paschen and Balmer
edges, but does not predict an increase in polarization longward of
the Paschen continuum nor as sharp a decrease shortward of the Balmer
continuum as is observed.
Title: Properties of the chromosphere-corona transition region
in Capella.
Authors: Haisch, B. M.; Linsky, J. L.
Bibcode: 1976ApJ...205L..39H
Altcode:
Analysis of recent ultraviolet observations of the Capella binary system
(Alpha Aur) indicates a dense geometrically narrow chromosphere-corona
transition region in the Capella system primary (G5 III) similar in
many respects to a solar active region. An examination of the coronal
energy balance, together with the coronal base pressure derived from
the line fluxes, predicts a corona with a mean temperature of 1.2
million K and a large stellar wind consistent with observations.
Title: A tensor formulation of the equation of transfer for
spherically symmetric flows.
Authors: Haisch, B. M.
Bibcode: 1976ApJ...205..520H
Altcode:
A tensor formulation of the equation of radiative transfer is derived
in a seven-dimensional Riemannian space such that the resulting
equation constitutes a divergence in any coordinate system. After being
transformed to a spherically symmetric comoving coordinate system, the
transfer equation contains partial derivatives in angle and frequency,
as well as optical depth due to the effects of aberration and the
Doppler shift. However, by virtue of the divergence form of this
equation, the divergence theorem may be applied to yield a numerical
differencing scheme which is expected to be stable and to conserve
luminosity. It is shown that the equation of transfer derived by this
method in a Lagrangian coordinate system may be reduced to that given
by Castor (1972), although it is, of course, desirable to leave the
equation in divergence form.
Title: An Analysis of the Chromospheric O I Lines in Arcturus
Authors: Haisch, B. M.; Linsky, J. L.; Weinstein, A.; Shine, R.
Bibcode: 1976BAAS....8..303H
Altcode:
No abstract at ADS
Title: Theoretical Wavelength Dependence of Polarization in Early-Type
Stars
Authors: Haisch, B. M.; Cassinelli, J. P.
Bibcode: 1976IAUS...70..375H
Altcode:
No abstract at ADS
Title: Polarization Models for Early-Type Stars
Authors: Haisch, B. M.; Cassinelli, J. P.
Bibcode: 1975BAAS....7..559H
Altcode:
No abstract at ADS
Title: A Tensor Formulation of the Equation of Transfer I. Application
to Plane Parallel Flows.
Authors: Haisch, B. M.
Bibcode: 1975BAAS....7..449H
Altcode:
No abstract at ADS
Title: Polarization by rotationally distorted electron scattering
atmospheres.
Authors: Cassinelli, J. P.; Haisch, B. M.
Bibcode: 1974ApJ...188..101C
Altcode:
The polarization to be expected from rotationally distorted early-type
stars is determined using results of calculations of the transfer of
linearly polarized light in extended atmospheres. Polarization as high
as about 6 percent is found for a disk envelope model and 2 percent
for a Roche atmospheric model. The factors controlling the direction of
the polarization are discussed. Plausible explanations are offered for
the anomalous wavelength dependence of both the degree of polarization
in the Wolf-Rayet star HD 50896 and of the direction of polarization
in the Be star HD 45677. Subject headings: atmospheres, stellar -
Be stars - polarization - radiative transfer - Wolf-Rayet stars
Title: Maximum Net Polarization for Rotationally Distorted Electron
Scattering Atmospheres.
Authors: Cassinelli, J. P.; Haisch, B. M.
Bibcode: 1973BAAS....5..337C
Altcode:
No abstract at ADS
Title: Photometric observations of the star cluster NGC 2141.
Authors: Burkhead, M. S.; Burgess, R. D.; Haisch, B. M.
Bibcode: 1972AJ.....77..661B
Altcode:
No abstract at ADS