Author name code: macqueen
ADS astronomy entries on 2022-09-14
author:"MacQueen, Robert"
------------------------------------------------------------------------
Title: Application of a New Technique for Deriving Prominence Mass
from SOHO EIT Fe XII (19.5 nm) Absorption Features
Authors: Gilbert, Holly R.; Falco, Lauren E.; Holzer, Thomas E.;
MacQueen, R. M.
Bibcode: 2006ApJ...641..606G
Altcode:
In a previous study we developed a new technique for deriving prominence
mass by observing how much coronal radiation in the Fe XII (19.5 nm)
spectral line is absorbed by prominence material. In the present work
we apply this new method, which allows us to consider the effects
of both foreground and background radiation in our calculations,
to a sample of different types of prominences (eruptive, quiescent,
and surging) observed during the period 1999 July through 2004
July. The masses of prominences involved in CMEs are not generally
measured, but the accurate determination of such masses may help in
assessing the dynamical importance of prominences in CME events. In
the present study, we find the average mass of our sample of quiescent
prominences to be 4.18×1014 g, while the average mass
of the eruptive prominences is 9.09×1014 g, and that of
surges is 1.53×1014 g.
Title: A New Technique for Deriving Prominence Mass from SOHO/EIT
Fe XII (19.5 Nanometers) Absorption Features
Authors: Gilbert, Holly R.; Holzer, Thomas E.; MacQueen, R. M.
Bibcode: 2005ApJ...618..524G
Altcode:
It is presently unclear what role prominences play in the initiation and
dynamics of coronal mass ejections (CMEs), although erupting prominences
are strongly correlated with CMEs. The masses of prominences involved in
CMEs are not generally measured, but the accurate determination of such
masses may help in assessing the dynamical importance of prominences in
CME events. In the technique for deriving prominence mass introduced in
the present work, we use observations of coronal radiation in the Fe XII
(19.5 nm) spectral line, which is absorbed by prominence material. This
new method allows us to consider the effects of both foreground and
background radiation in our calculations, and it can be applied to
both quiescent and erupting prominences by using two versions of the
method, which we label the ``spatial-interpolative'' version and the
``temporal-interpolative'' version. When both versions can be applied
to the same event, we find that the temporal-interpolative approach
yields the more accurate results. We have applied both versions to
an erupting prominence observed on 1999 July 12 (this prominence has
an associated CME), and we find that the two approaches result in
similar mass determinations: (6.0+/-2.5)×1014g for the
temporal-interpolative approach and (7.4+/-4.6)×1014g for
the spatial-interpolative approach.
Title: The mass content of Coronal Mass Ejections
Authors: Burkepile, J. T.; Hundhausen, A. J.; MacQueen, R. M.; deToma,
G.; Darnell, J. A.; Gilbert, H. R.
Bibcode: 2004AAS...204.1806B
Altcode: 2004BAAS...36Q.683B
The total mass content of solar Coronal Mass Ejections (CMEs) can vary
greatly between events. Most CMEs have estimated masses between 10e+14
and 10e+16 grams of material. It is believed that most of the CME
material is coronal in origin (Hildner et al. 1975) but the source of
the mass remains largely unknown. The large fields-of-view of the LASCO
C2 and C3 coronagraphs coupled with observations of the low corona from
the MK4 K-Coronameter at the Mauna Loa Solar Observatory provide the
observations needed to examine CME masses over a wide range of coronal
scale heights. We utilize these observations to estimate both the amount
of material which is ejected from the very low corona and the amount
of mass which is 'swept up' by the CME as it propagates outward. This research is funded by the National Science Foundation.
Title: Dust Near The Sun
Authors: Mann, Ingrid; Kimura, Hiroshi; Biesecker, Douglas A.;
Tsurutani, Bruce T.; Grün, Eberhard; McKibben, R. Bruce; Liou,
Jer-Chyi; MacQueen, Robert M.; Mukai, Tadashi; Guhathakurta, Madhulika;
Lamy, Philippe
Bibcode: 2004SSRv..110..269M
Altcode:
We review the current knowledge and understanding of dust in the inner
solar system. The major sources of the dust population in the inner
solar system are comets and asteroids, but the relative contributions
of these sources are not quantified. The production processes inward
from 1 AU are: Poynting-Robertson deceleration of particles outside of
1 AU, fragmentation into dust due to particle-particle collisions,
and direct dust production from comets. The loss processes are:
dust collisional fragmentation, sublimation, radiation pressure
acceleration, sputtering, and rotational bursting. These loss processes
as well as dust surface processes release dust compounds in the
ambient interplanetary medium. Between 1 and 0.1 AU the dust number
densities and fluxes can be described by inward extrapolation of 1
AU measurements, assuming radial dependences that describe particles
in close to circular orbits. Observations have confirmed the general
accuracy of these assumptions for regions within 30° latitude of the
ecliptic plane. The dust densities are considerably lower above the
solar poles but Lorentz forces can lift particles of sizes < 5 μm
to high latitudes and produce a random distribution of small grains
that varies with the solar magnetic field. Also long-period comets
are a source of out-of-ecliptic particles. Under present conditions
no prominent dust ring exists near the Sun. We discuss the recent
observations of sungrazing comets. Future in-situ experiments should
measure the complex dynamics of small dust particles, identify the
contribution of cometary dust to the inner-solar-system dust cloud, and
determine dust interactions in the ambient interplanetary medium. The
combination of in-situ dust measurements with particle and field
measurements is recommended.
Title: The Acceleration of Coronal Mass Ejections
Authors: Burkepile, J. T.; Hundhausen, A. J.; MacQueen, R. M.; Detoma,
G.; Darnell, J. A.; Gilbert, H. R.
Bibcode: 2003AGUFMSH21A..01B
Altcode:
To determine quantitative estimates of the net force acting on a
CME requires knowledge of the CME acceleration as a function of
distance from the solar surface. The CME acceleration is determined
directly from the observed time-height trajectory of the event by two
methods: (a) sucessive differentials and (b) the use of polynomial
and exponential function curve fitting to the trajectory, followed by
successive derivatives. We examine the acceleration of a set of Coronal
Mass Ejections (CMEs) observed over a wide range of coronal scale
heights by combining observations of the low corona from the Mauna
Loa Solar Observatory and the Extreme ultraviolet Imaging Telescope
(EIT) on the Solar and Heliospheric Observatory (SOHO) spacecraft with
observations from the LASCO coronagraphs onboard SOHO. We apply both of
the above techniques to the events and conclude that CME acceleration
is greatest in the low corona despite the strong force of gravity
in that region. (In addition, CME start times determined from outer
coronal (LASCO) observations alone tend to be systematically later
than the actual start times, most likely due to the fact that LASCO
observations cannot observe CME acceleration in the low corona.)
Title: The J- and K-Band Brightness of the Solar F Corona Observed
during the Solar Eclipse on 1998 February 26
Authors: Ohgaito, R.; Mann, I.; Kuhn, J. R.; MacQueen, R. M.;
Kimura, H.
Bibcode: 2002ApJ...578..610O
Altcode:
We analyze J- and K-band observations of the 1998 solar eclipse
and derive the F-corona brightness in the K band between 3 and
7 Rsolar from the center of the Sun and in the J band
out to 5 Rsolar. The falloff in the K-band brightness
from 3 to 7 Rsolar is fitted with a radial power law
with exponent -2.4+/-0.1 at the solar equator and with exponent
-2.9+0.2-0.1 at the solar pole. This slope is
gentler than that derived from observations in 1983 but is steeper
than that derived from observations for the 1991 eclipse. The radial
profiles agree well with models that explain the F corona with weakly
absorbing dust particles. Comparison of the J- and K-band brightness at
3 Rsolar from the center of the Sun indicates a reddening
of the F corona with respect to the solar spectrum. The reddening is,
however, less pronounced compared to the F corona observed during the
1983 total solar eclipse. This fact may be attributed to a change in
the composition of dust near the Sun. As with the radial profiles, the
reddening in 1998 is better explained with models that assume weakly
absorbing rather than strongly absorbing dust particles in the solar
corona. Similar to recent eclipse observations, we do not detect an
excess emission feature of near-solar dust in the F corona. We hence
can reject the hypothesis that suggests a correlation between the
detection of an emission feature and the solar activity cycle.
Title: Narrow Coronal Mass Ejections
Authors: Gilbert, Holly R.; Serex, Elizabeth C.; Holzer, Thomas E.;
MacQueen, R. M.; McIntosh, Patrick S.
Bibcode: 2001ApJ...550.1093G
Altcode:
Narrow coronal mass ejections (CMEs), defined arbitrarily as events
whose apparent angular width is 15° or less, are a small subset of
all CMEs. Little is known of the properties of these events and whether
these properties differ from those of the larger, more typical CMEs. We
have included in this study 15 narrow CMEs observed in the period from
1999 March through December, and we have examined their structure,
angular size, projected radial velocity (speed), and likely surface
associations. We find it useful to break these events into two classes:
structured and unstructured. Unstructured narrow events are generally
narrower and slower than the structured events, but both classes of
narrow CMEs exhibit speeds similar to those of larger CMEs. We found
that 11 of 15 events studied may be traced to regions on the solar
surface near a relatively sharp bend in a polarity-reversal line,
as revealed from Hα synoptic maps. We contrast the properties of the
narrow CMEs with those of the larger CME population.
Title: Solar Coronal Brightness Changes and Mass Ejections during
Solar Cycle 22
Authors: MacQueen, R. M.; Burkepile, J. T.; Holzer, T. E.; Stanger,
A. L.; Spence, K. E.
Bibcode: 2001ApJ...549.1175M
Altcode:
Observations of the brightness of the outer solar corona from the
Solar Maximum Mission (SMM) coronagraph during solar cycle 22 (1980,
then 1984-1989) are compared with the occurrence rate and the mass of
coronal mass ejections (CMEs) observed during this period. We find that
the brightness and, hence, mass of the outer corona increased by more
than a factor of 4 from solar minimum (1986) to late 1989, when the
SMM ceased operation. The peak brightness (mass) in 1989 was roughly
equivalent to that observed in the latter part of 1980. Accompanying a
sharp increase in brightness (mass) of the corona in early 1989 was a
concomitant increase in both the occurrence rate and the average mass
of CMEs.
Title: A New Method of Determining Line-of-Sight Velocity Using
MLSO/CHIP He I 1083 nm Observations
Authors: Holzer, T. E.; Gilbert, H. R.; Elmore, D. F.; MacQueen, R. M.
Bibcode: 2000SPD....3102107H
Altcode:
A new method for determining line-of-sight velocity has been developed
for the MLSO/CHIP He I 1083 nm instrument. The method involves tuning
the Lyot-type spectral filter to seven different positions during
each observing sequence (lasting about 3 minutes). The algorithm for
line-of-sight velocity determination using these seven filter positions
yields an accuracy of better than 10 km/s over a line-of-sight velocity
range from -100 km/s to +100 km/s. The method is applicable to the
observation of filaments, surges, sprays, and other features exhibiting
sufficiently strong absorption or emission in the 1083 nm line. It
therefore will be particularly useful in the study of eruptive events
seen against the solar disk, such as filament eruptions associated with
earthward-directed coronal mass ejections. The High Altitude Observatory
(HAO) is part of the National Center for Atmospheric Research (NCAR),
which is sponsored by the National Science Foundation under the
management of the University Corporation for Atmospheric Research.
Title: Prominence Densities as Derived from SOHO/EIT Fe XII (195
Angstrom) Absorption Features
Authors: Gilbert, H.; Mize, L.; Holzer, T.; MacQueen, R.
Bibcode: 2000SPD....31.0218G
Altcode: 2000BAAS...32..814G
Prominences often appear in absorption when the sun is viewed in EUV
emission lines formed at coronal temperatures. The coronal EUV radiation
at wavelengths less than 504 anstroms undergoes Lyman continuum
absorption by both hydrogen and helium (i.e., the coronal radiation
ionizes hydrogen and helium atoms from their ground states). We can
thus infer prominence column densities by measuring the amount of
coronal radiation absorbed by prominence material along the line of
sight, and by making assumptions concerning the ionization state and
the helium abundance characterizing the prominence plasma. We do so
by measuring 195 angstrom intensity along lines of sight inside and
outside prominences, both just on the disk and just off the limb. Our
absorption measurements are made using Fe XII (195 angstroms) data
from the Extreme Ultraviolet Imaging Telescope (EIT) on board the
SOHO spacecraft. Initial results using our technique yield prominence
densities on the order of 1010 cm-3. This is
the first step in reaching our ultimate objective of attaining a
quantitative measure of total prominence mass, which may be important
in the dynamical processes involved in Coronal Mass Ejection initiation
and evolution.
Title: Temporal properties of He I 1083 nm dark points
Authors: MacQueen, R. M.; Hendrickson, M. A.; Woods, J. C.; Lecinski,
A. R.; Elmore, D. F.; White, O. R.
Bibcode: 2000SoPh..191...85M
Altcode:
The intensity of a sample of large, high-contrast and isolated dark
points has been observed with full-disk images in the light of He i
1083 nm from the Chromospheric Helium line Intensity Photometer (CHIP)
on Mauna Loa, Hawaii. Temporal variations in the intensity encompassing
a broad range of time scales have been recorded. Long-term changes
in the intensity, although highly variable, are characterized by
e-folding times on the order of 5 h. Superposed on these variations
are frequent intensity variations, which occur over time scales
ranging from the typical observing cadence of 3 min, to tens of
minutes. Microflares-involving intensity changes of at least 50%
over periods of minutes are observed frequently. Rapid cadence (
min) observations reveal differences between rise and decay times and
shorter-term variations in the intensity profiles of these microflares.
Title: The J- and K-Band brightness of the solar F-corona observed
during the solar eclipse on February 26, 1998.
Authors: Ohgaito, R.; Mann, I.; Kuhn, J. R.; MacQueen, R. M.; Lin,
H.; Edmunds, D.
Bibcode: 1999BAAS...31.1159O
Altcode:
No abstract at ADS
Title: The J- and K-Band Brightness of the Solar F-Corona Observed
During the Solar Eclipse on February 26, 1998
Authors: Ohgaito, R.; Mann, I.; Kuhn, J. R.; MacQueen, R. M.; Lin,
H.; Edmunds, D.
Bibcode: 1999DPS....31.5502O
Altcode:
The solar eclipse on February 26 1998 was observed from an open flying
aircraft at an altitude of almost 6 km above the Pacific about 800
km southwest from Panama City. The solar F-corona, produced by light
scattering and thermal emission from dust around the Sun, was observed
with a low atmospheric straylight level in the J and K-band over a field
of view of 7 degrees. The data show no indication for the existence of
pronounced brightness features in the solar F-corona, such as often
discussed as evidence for the existence of dust rings. The shape
of the corona is slightly elliptic but symmetric in the north-south
direction. The data show a reddening of the coronal brightness compared
to the solar spectrum. The color of the F-corona is influenced by the
temperature of dust particles, by their spatial distribution, as well
as by their size distribution that influences especially the forward
scattering that is seen in the corona from dust particles close to the
observer. We will discuss the color variation from the solar equator
to the solar pole and with distances from the Sun and compare it to
models of dust light scattering and thermal emission.
Title: Probable Detection of a Bright Infrared Coronal Emission Line
of Si IX near 3.93 Microns
Authors: Kuhn, J. R.; MacQueen, R. M.; Streete, J.; Tansey, G.; Mann,
I.; Hillebrand, P.; Coulter, R.; Lin, H.; Edmunds, D.; Judge, P.
Bibcode: 1999ApJ...521..478K
Altcode:
We report here the probable detection of an emission line of Si
IX that was observed from an open C130 aircraft over the Pacific
Ocean during the 1998 total solar eclipse. Although the IR data
themselves are inconclusive because of the uncertainty in the precise
central wavelengths of the narrowband filters during the eclipse,
the consistency of the measured IR limb excess with simultaneous EUV
emission measured by SOHO/Coronal Diagnostic Spectrometer and the EUV
Imager Telescope support our detection claim. This line appears to
be the brightest IR coronal line yet observed, and its existence may
significantly improve future prospects for obtaining optical coronal
magnetic field measurements.
Title: Initial CHIP He I Observations of Solar Limb Activity
Authors: MacQueen, R. M.; Blankner, J. G.; Elmore, D. F.; Lecinski,
A. R.; White, O. R.
Bibcode: 1998SoPh..182...97M
Altcode:
A new instrument capable of 3-min time resolution full-disk and limb
observations in the Hei 1083 nm spectral line has been in operation
at the High Altitude Observatory's Mauna Loa Solar Observatory (MLSO)
since April 1996. We discuss instrument capabilities and performance
and present some initial observations of limb activity from the first
year of instrument operation. We compare limb Hei and Hα observations
of quiescent and active prominences, comment on the role of Doppler
shifts in interpreting the Hei observations, and illustrate the use
of disk/limb Hei observations of a CME-associated eruptive filament
in mass-ejection studies.
Title: Chromospheric Helium Imaging Photometer (an Instrument for
High Time Cadence 1083-nm Wavelength Solar Observations)
Authors: Elmore, David F.; Card, Gregory L.; Chambellan, Clarke W.;
Hassler, Donald M.; Hull, Howard L.; Lecinski, Alice R.; MacQueen,
Robert M.; Streander, Kim V.; Streete, John L.; White, Oran R.
Bibcode: 1998ApOpt..37.4270E
Altcode:
No abstract at ADS
Title: A Study of the Origin and Dynamics of Coronal Mass Ejections
Authors: Burkepile, J. T.; Hundhausen, A. J.; Bagenal, F.; McAllister,
A. H.; MacQueen, R. M.
Bibcode: 1997SPD....28.0125B
Altcode: 1997BAAS...29..883B
Coronal mass ejections (CMEs) are dynamic events that typically
involve the expulsion of 10(15) to 10(16) grams of coronal and
chromospheric plasma into interplanetary space. The relationship
between mass ejections and other forms of solar activity, especially
those evident on the solar disk, remains unclear. In an attempt to
accurately determine CME onset times and origins, we have combined
observations from the Solar Heliospheric Observatory (SOHO) Large
Angle Spectroscopic Coronagraphs (LASCO), the SOHO Extreme Ultraviolet
Imaging, the Mauna Loa Observatory (MLO) white light and chromospheric
instruments and the Yohkoh Soft X-ray Telescope. Mass ejections believed
to have occurred both at or near the limb of the sun and on the solar
disk have been employed in the comparison. When available, the MLO and
LASCO white light observations have been combined to determine material
trajectories, and hence accurate CME onset times. The evolution of
the magnetic fields and associated plasma structures prior to, during
and after mass ejections have been examined by comparing He-I and Hα
chromospheric disk signatures with EUV and X-ray observations.
Title: Solar Chromospheric and Coronal Explorer
Authors: Walker, Arthur B.; Scherrer, Philip H.; Hoover, Richard B.;
Tandberg-Hanssen, Einar; Barbee, Troy W.; Ling, James C.; MacQueen,
R. M.; Timothy, J. Gethyn; Adamson, Paul; Mennzel, Mike T.; Petheram,
John C.; Shattuck, Paul L.
Bibcode: 1996SPIE.2804..286W
Altcode:
The presence of the solar magnetic field has a profound effect on
the structure of the lower chromosphere, and is responsible for the
formation of the upper chromosphere and the corona, and the acceleration
of the solar wind. The variation of the field induces variations in
the chromosphere and the corona on time scales from 0.001 seconds to
centries. SOHO, and subsequent approved solar missions such as TRACE
will bring powerful observational capabilities to bear on critical
questions relating to solar variability. However, the most fundamental
question--how energy is transferred from the magnetic field into the
solar plasma--will require observations of diagnostic quality on a
spatial scale of 50 - 100 kilometers; this is an order of magnitude
beyond the capability of any planned mission. Our mission concept,
the Solar Chromospheric and Coronal Explorer (SCCE) is designed to
investigate the mechanisms underlying the variability of the solar
atmosphere, by attaining spectroscopic observations of the solar
atmosphere over a wide range of temperatures (4,500 K to 100,000,000 K),
with very high angular (0.1 arcseconds) and temporal (0.001 seconds)
resolution, that will permit models of the physical processes that
underlie the phenomena of solar activity to be formulated and tested
at the scale, 50 - 75 kilometers that appears to be fundamental. The
architecture of the SCCE is based on advances in multilayer optics,
which permit broad spectral response, and high angular and spectral
resolution to be achieved in a volume, and at a cost that is compatible
with deployment within the fiscal and physical constraints of the
MIDEX program.
Title: BOOK REVIEW: Total Eclipses of the Sun (Expanded
Edition). J. B. Zirker.
Authors: MacQueen, R. M.
Bibcode: 1996Icar..123..585M
Altcode:
No abstract at ADS
Title: The Large-Scale Density Structure of the Solar Corona and
the Heliospheric Current Sheet
Authors: Guhathakurta, Madhulika; Holzer, Thomas E.; MacQueen, R. M.
Bibcode: 1996ApJ...458..817G
Altcode:
We have investigated the three-dimensional distribution of the
polarization-brightness product (PB) and then quantitatively
determined the electron density distribution relative to the
inferred heliographic current sheet during the declining phase
of solar cycle 20 (1973-1976). The current sheet is taken as the
center of the bright, dense structures from combined synoptic
pB data from ground-based K-coronameter and the white- light
coronagraph aboard Skylab. Analyses of pB scans as a function of
minimum distance from the current sheet (θmin) over the
radial distance range 1.13 to 5.0 Rsun (from Sun center)
led to the following new results: (1) a quantitative description
of pB obtained around the inferred neutral line is given by the
following equation: pB(p,θmin) = pBp(p)
+ [pBcs(p)-pBp(p)]e-θmin2/w2(r), where p is the shortest distance to the line of sight from
the Sun center, pBcs(p) and pBp(P) are the
observed polarized brightness at the current sheet and the poles,
respectively, and w(r) is the half-width of the distribution;
(2) the electron density obtained by inverting the pB data
is given by N(r,θmg) = Np(r) +
[Np(r)-Np(r)]e-θmg2/w2(r)d ,
where N(r,θmg) is the number of free electrons
per cm3, Ncs(r) and Np(r) are the
electron densities at the current sheet and the poles, respectively,
and θmg is the magnetic latitude. Here θmg is
given by θmg = [-cos θ sin α sin (φ-φ0)
+ sin θ cos α] where θ and φ are heliographic latitude and
longitude, α is the tilt angle of the dipole axis with the rotation
axis, and φ0 is the intersection of the heliomagnetic and
heliographic equators; (3) during the period studied (the last third
of the solar cycle), the mean pB at the current sheet and above the
polar holes is approximately independent of the phase of the solar
cycle; and (4) the organization of pB data about the neutral line
allows inference of the boundary of the polar coronal holes. The
usefulness of one-dimensional white-light density constraint in solar
wind modeling has already been demonstrated by Habbal et al. The
present three-dimensional model should prove very useful in better
understanding of the global hydromagnetic structure of the corona
and the solar wind, relating as it does to the magnetic structure
of the corona, as opposed to heliocentric coordinates. For example,
the density model could provide constraints on coronal temperature,
flow velocity, and magnetic structure subject to a suitable analysis
of geometric effects, which in turn would provide constraints on energy
balance in the coronal expansion.
Title: The Role of Particle Size in Producing the F-Coronal Scattered
Brightness
Authors: MacQueen, R. M.; Davidson, W. C.; Mann, I.
Bibcode: 1996ASPC..104..349M
Altcode: 1996IAUCo.150..349M; 1996pcdi.conf..349M
No abstract at ADS
Title: Observation and analysis of the F-corona brightness
Authors: Mann, I.; MacQueen, R. M.
Bibcode: 1996AdSpR..17c..53M
Altcode: 1996AdSpR..17...53M
In the context of dust measurements on a solar probe, we present an
analysis of a 1991 eclipse observation by Hodapp et al. /1/ with respect
to the solar F-corona brightness (published in MacQueen and Greeley,
/2/). Although the data are limited by observing conditions, we can
still gain some information which may be compared with our present
knowledge about the interplanetary dust cloud based on the analysis of
zodiacal light data, which describe the dust in regions outward from
the sun. Past visible light measurements showed that the F-corona
has roughly the same brightness in the ecliptic and over the poles,
but that the radial gradient of the latter is steeper. In the 1991
infrared observations, the ecliptic radial gradient is flatter than
has been observed in the visible, whereas the polar radial gradient
is rather similar to past, visible spectral region observations. This
appears to point to the existence of different components in the dust
cloud as also discussed to explain the zodiacal light /3/. Also in the
present data there is no clear signature for the beginning of the dust
free zone around the sun, one conclusion being that dust (of some type)
possibly approaches the sun to within 4 solar radii. As far as the size
distribution of dust in the solar vicinity is concerned we discuss a
study by Davidson et al. /4/, which shows that the present F-corona
data can be fitted with distinctly different size distributions.
Title: ACOS: HAO's next generation Coronal Observing Facility at
Mauna Loa
Authors: Hassler, D. M.; Elmore, D. F.; Lecinski, A.; Streander,
K.; Burkepile, J.; Stanger, A.; Hundhausen, A. J.; Rottman, G. J.;
MacQueen, R. M.
Bibcode: 1995SPD....26..721H
Altcode: 1995BAAS...27..970H
No abstract at ADS
Title: Solar Coronal Dust Scattering in the Infrared
Authors: MacQueen, R. M.; Greeley, Bradford W.
Bibcode: 1995ApJ...440..361M
Altcode:
Observations of the total and polarized brightness of the solar corona
at wavelength 2.12 microns during the total solar eclipse of 1991 July
11 are employed to separate the contribution of the electron-scattered
component and the remaining, nonpolarized component, the latter
dominating in the outer corona. After corrections are applied to account
for a two-component sky or instrument background, the brightness
of the ecliptic and polar corona are fitted by r-1.9 and
r-2.3, respectively, over the radial distance range 3-8
solar radii from Sun center. The ecliptic outer-coronal brightness is
compared with a Mie-scattering model of interplanetary dust particles
based upon three particle-size distributions deduced from, respectively,
lunar microcrater counts (Lamy & Perrin 1986), interplanetary
dust flux measurements (Gruen et al. 1985), and for an arbitrary
population of large particles (radii greater than 3 x 10-5
cm). Particle physical characteristics and spatial distributions are
those assumed in past studies of the zodiacal cloud. For reasonable
assumed space number densities of particles, the models agree with the
magnitude of observed ecliptic coronal brightness. But in all cases,
the models predict a steeper brightness falloff with radial distance
that that observed, with those models for which the power-law exponent
for the space distribution is v = 1.3 being the most discrepant with
the observed radial gradient.
Title: Scattering models for the solar infrared F-corona brightness
Authors: Davidson, W. C.; MacQueen, R. M.; Mann, I.
Bibcode: 1995P&SS...43.1395D
Altcode:
Model calculations are made of the infrared brightness in the solar
F-corona motivated by recent infrared solar eclipse observations. Two
different approaches are employed to describe the scattering properties
of interplanetary dust : Mie scattering theory and diffraction theory,
with and without an isotropic scattering term. In addition. two
different particle size distributions are used in the calculations and
the resultant line of sight brightness is compared with observational
data of the solar F-corona between 3 and 8 solar radii ( R) in the
ecliptic plane. It is found that the use of diffraction theory without
an isotropic scattering contribution gives a very poor match with the
observations, for both assumed particle size distributions. However,
both the diffraction theory including isotropic scattering and the
Mie scattering theory agree reasonably with the observed brightness,
and especially its radial slope within the corona. for the model size
distribution which is dominated by large particles. Only Mie theory
may be employed in describing the second model size distribution
because diffraction theory poorly describes the scattering due to
the small particles which dominate this size distribution. It is
concluded that the derivation of particle size distributions from the
F-coronal brightness is still ambiguous and a further analysis needs
either improved observations, or the application of further reasonable
physical assumptions.
Title: CFHT eclipse observation of the very fine-scale solar corona
Authors: Koutchmy, S.; Belmahdi, M.; Coulter, R. L.; Demoulin, P.;
Gaizauskas, V.; MacQueen, R. M.; Monnet, G.; Mouette, J.; Noens,
J. C.; November, L. J.
Bibcode: 1994A&A...281..249K
Altcode:
At the July 11, 1991 solar total eclipse, a modern large optical
telescope, Canada-France-Hawaii telescope (CFHT), was used to
probe the solar corona. The best possible pictures were obtained
with the CFHT, using fast imaging techniques and post-facto image
selection and processing. Several cameras were run during totality
to acquire sub-arcsec spatial resolution white-light images, with
both narrow-band and broad-band filters. The setup and the observing
procedure are described. Preliminary results, together with an
evaluation of the merits of the experiment, are given, as well as a
sample of images. Fine-scale coronal features were observed for the
first time in a time series, confirming the importance of plasmoid-like
activity in the inner corona. The observation of the smallest coronal
feature ever reported is analyzed, giving a typical cross-section of
0.4 +/- 0.1 arcsec. On a larger scale, dark loops around a foreground
prominence are resolved for the first time, suggesting that sheet-like
voids exist above a filament channel.
Title: The solar F-corona at 2.12 pin: calculations of near-solar
dust in comparison to 1991 eclipse observations
Authors: Mann, L.; MacQueen, R. M.
Bibcode: 1993A&A...275..293M
Altcode:
A comparison of 1991 solar eclipse coronal observations over the range
of 3Rsun-8Rsun at wavelength 2.12 μm, with model
calculations of thermal emission and scattering from interplanetary dust
particles (IDPs) is presented. The observed brightness in the ecliptic
plane shows a monotonic decrease which can be approximated with a
radial power law with exponent 2. No signature in the brightness,
due to enhanced dust concentration or emission near the Sun can be
detected. The modelling attempts result in an average deviation,
relative to the observations, of less than 12%, under reasonable
assumptions about the spatial distribution and optical and thermal
properties of the IDPs. It is only possible to match the observational
data with a model of scattering and thermal emission where particles can
approach up to 3Rsun towards the Sun. The data suggest that
it is necessary to alter the local variation of number density of dust
particles within 10Rsun. The deduced temperature of the IDPs
is about 10% below their blackbody temperature, and the best fit with
observations involves a variation in the IDP albedo with distance from
the Sun, suggesting physical changes to the near-solar IDP population.
Title: The three-dimensional structure of `loop-like' coronal mass
ejections
Authors: MacQueen, R. M.
Bibcode: 1993SoPh..145..169M
Altcode:
We have measured the brightness and latitudinal extent of the depleted
(cavity) region behind the leading edge of three coronal mass ejection
(CME) events from the Skylab epoch. The events chosen are among those
believed to be typical of non-impulsive, `loop-like' CMEs (Sime,
MacQueen, and Hundhausen, 1984). The pre-event coronal brightness has
been matched by a model corona, assuming both a background contribution
and a contribution from a range of hypothetical streamer models,
distinguished by differing longitudinal extent. Then, assuming that
the cavities are voided regions in which the local electron density
is negligible, we estimate their minimum line-of-sight extent and find
them to be comparable to, or greater than, their measured latitudinal
extent. As a result, we suggest this unambiguously demonstrates
the three-dimensional nature of these — and likely, this class of
— events.
Title: The Solar Corona from 3 to 8 Solar Radii: Comparison of
Calculations and New Observational Results
Authors: Mann, I.; MacQueen, R. M.
Bibcode: 1992DPS....24.1102M
Altcode: 1992BAAS...24..951M
No abstract at ADS
Title: A search during the 1991 solar eclipse for the infrared
signature of circumsolar dust
Authors: Hodapp, Klaus-Werner; MacQueen, R. M.; Hall, Donald N. B.
Bibcode: 1992Natur.355..707H
Altcode:
THEORETICAL suggestions1-3 that there should be a ring
of dust in near-ecliptic orbit about the Sun were supported by
observations, during a total solar eclipse on 12 November 1966, of
enhanced infrared emission4-6 from the solar corona at a
distance of 4 Rsolar from the Sun's centre. The infrared emission was
attributed to the sublimation of dust grains as they spiral into the
Sun because of the Poynting-Robertson effect, by which solar radiation
creates a tangential drag. Two months after the 1966 eclipse, the
feature at 4 Rsolar was seen again in observations from a stratospheric
balloon-borne coronagraph, as were additional features at 3.5, 8.7
and 9.2 R (ref. 6). Observations since then, however, have failed
unambiguously to corroborate the earlier observations. We searched
for excess infrared emission in the solar equatorial plane during the
11 July 1991 eclipse, using a wide-angle infrared camera on Mauna Kea,
but failed to find any signature of dust evaporation. We argue that the
earlier observations were credible, and therefore that the circumsolar
dust ring is a transient feature, perhaps due to the injection of dust
into near-solar space by a Sun-grazing comet.
Title: A Search for the Infrared Signature of Circumsolar Dust
Authors: MacQueen, R. M.; Hodapp, K. -W.; Hall, D. N. B.
Bibcode: 1991BAAS...23R1449M
Altcode:
No abstract at ADS
Title: Sungrazing comets observed by the solar maximum mission
coronagraph
Authors: MacQueen, R. M.; St. Cyr, O. C.
Bibcode: 1991Icar...90...96M
Altcode:
Ten sungrazing comets were discovered by the High Altitude Observatory's
white light coronagraph on the NASA Solar Maximum Mission spacecraft
during an observing period which covered about 6 years. In addition,
observation of another sungrazing comet discovered by the SOLWIND
coronagraph was confirmed. The comets exhibited a wide range of
brightness near the Sun, spanning roughly 8 astronomical magnitudes. No
comets were observed postperihelion, and no discernible coronal effects
could be detected as a result of any comet disappearance. The comet
apparent motions and orientation of tails are consistent with all of the
comets belonging to the Kreutz sungrazer group, a conclusion in support
of the orbital analysis of nine of the objects by Marsden (1989). The
observing programs employed by the instrument to detect coronal
mass ejection events are shown to be well-suited for the detection
of sungrazers. The appearance of these comets is seen to be highly
episodic over the time period of SMM coronagraph operation. Estimates
of the comet head properties, including size, are offered, based upon
the observed comet behavior.
Title: The Effect of Solar Activity on Sungrazing Comets
Authors: St. Cyr, O. C.; Hundhausen, A. J.; MacQueen, R. M.
Bibcode: 1990BAAS...22.1323S
Altcode:
No abstract at ADS
Title: SMM Observations of Sungrazing Comets
Authors: MacQueen, R. M.; St. Cyr, O. C.; Hundhausen, A. J.
Bibcode: 1989BAAS...21.1144M
Altcode:
No abstract at ADS
Title: The solar coronal mass ejection of 20 21 November, 1973
Authors: MacQueen, R. M.; Holzer, T. E.
Bibcode: 1988SoPh..116..349M
Altcode:
The coronal transient event of 20-21 November is unusual in that its
appearance is distinctly non-loop-like; rather, the transient resembles
a confined ray or fan-like volume. Studies of the distribution of the
coronal material with time indicate that this is a mass ejection event,
involving about 1 × 1015 g of material from the lower
corona. Analysis of the polarization signal of the event suggests that
the event is associated with chromospheric activity in a region near
longitude E68. The observed properties (distributions in brightness
and polarization) of the transient are compared with the properties
of a well-studied event of typical loop-like appearance, but rotated
to simulate an `edge-on' appearance; the differences suggest that
the 20-21 November event is not such an edge-on, loop-like transient,
but rather is most simply described as an axisymmetric-cylindrical or
conical volume, the boundaries of which remain constant over the events'
lifetime. On this basis, the variation of the transient spatial density
with height and the variation of density with time can be specified
rather more certainly than for previously-studied coronal mass ejection
events. Densities are found to range from 3 × 10−16
g cm−3 at 2.1 R⊙ heliocentric height early
in the event to 1 × 10−18 g cm−3 at 4.0
R⊙ late in the event. Typical temporal variations of the
ejected material (at a given heliocentric height) are found to be on the
order of 10−18 g cm−3 s−1. The
mass and momentum balance in the event have been estimated from the
observed parameters, employing a multiparameter approach. We find that a
model with modest mass flux typified by material speed u0 ≲
50 km s−1 and a near balance between the event's pressure
gradient force and gravity — with possibly a small hydromagnetic
wave contribution to the total pressure — is consistent with the
observations. The kinetic energy of the event, determined from the
motion of the center of mass of the ejected material, is only about
1026 ergs, and thus is the smallest for any solar mass
ejection studied to date.
Title: Measurement of the 3-dimensional positions of type III bursts
in the solar corona.
Authors: Poquerusse, M.; Steinberg, J. L.; Caroubalos, C.; Dulk,
G. A.; MacQueen, R. M.
Bibcode: 1988A&A...192..323P
Altcode:
The Stereo 5 experiment observed the Sun at 60 and 30 MHz simultaneously
on the Earth (Nançay), and on the Soviet spacecraft Mars 7. It recorded
many normal type III's and type IIIb's during the period 1974 Jan
10 to 19 at a time when the "stereo" angle Earth-Sun-spacecraft was
large enough (≈35°) to allow an accurate triangulation. The time
delay Δt of type III bursts between the two observing stations was
measured with an uncertainty of ≈0.1 s. A ground interferometer
furnished a 2-dimensional position at 75 MHz with an uncertainty
of ≈0.1 R_sun;. Combining the two, the authors calculate for the
first time the three dimensional positions of type III sources in
the corona. Simultaneous observations of the corona in visible light
from Skylab allow the apparent radio source positions to be related
to slowly evolving coronal structures.
Title: A New High-Resolution CCD Spectrometer for the Mcdonald
Observatory 2.7-METER Telescope
Authors: Tull, P. J.; Macqueen, R. G.
Bibcode: 1988igbo.conf...52T
Altcode: 1988igbo.conf...52M
The authors have developed a reflecting analogue of the white-pupil
spectrograph concept that was proposed by Baranne (1972). The general
configuration of this spectrograph is given, as well as the reasoning
behind the decisions that have determined its design.
Title: Solar Physics. (Book Reviews: Progress in Solar Physics)
Authors: MacQueen, R. M.
Bibcode: 1986Sci...233.1333D
Altcode:
No abstract at ADS
Title: Obituary
Authors: Eddy, J. A.; MacQueen, R. M.
Bibcode: 1986SoPh..104..257E
Altcode: 1986SoPh..104..257.
No abstract at ADS
Title: Gordon Allen Newkirk, Jr., 1928 - 1985.
Authors: Eddy, J. A.; MacQueen, R. M.
Bibcode: 1986SoPh..104..256E
Altcode:
No abstract at ADS
Title: The propagation of coronal mass ejection transients
Authors: MacQueen, R. M.; Hundhausen, A. J.; Conover, C. W.
Bibcode: 1986JGR....91...31M
Altcode:
Measurements of the direction of propagation of 29 coronal mass
ejection events observed during the Skylab epoch (1973-1974) and 19
events observed during the SMM epoch (1980) reveal that the former
undergo an average 2.2° equatorward deflection, while the latter do not
deviate signficantly from radial motion. No differences between eruptive
prominence-associated or flare-associated events can be detected for
either epoch. The results suggest that coronal mass ejection events
are influenced by the background coronal magnetic and flow patterns;
the nonradial forces affecting the Skylab epoch mass ejections arise
from the large-scale dipolar magnetic field and flow configuration
present at that time.
Title: Coronal Magnetic Fields - a Mini Survey
Authors: MacQueen, R. M.
Bibcode: 1986ASSL..123....5M
Altcode: 1986shtd.symp....5M
Some recent progress in understanding the nature of the evolution of the
global coronal magnetic field is reviewed. Particularly, the efforts
of Hoeksema (1984) in defining the character of the evolving modes
of the potential coronal field are compared with the currently-known
evidence for evolution of coronal white light structures. Recent
work in examining the soft X-ray intensity of coronal holes over a
major portion of the solar cycle is noted, as are two new studies
investigating the relation of coronal mass ejections to the ambient
global coronal magnetic field.
Title: Broadening of looplike solar coronal transients
Authors: MacQueen, R. M.; Cole, D. M.
Bibcode: 1985ApJ...299..526M
Altcode:
The broadening of the tops of nine outwardly expanding looplike
coronal mass-ejection transients observed during 1973-1974 and 1980
has been examined. Five of the nine transients exhibit increased
breadth with time (height); although the rates vary widely, no event
shows an increase which can be fitted by a power-law form with a
greater-than-linear increase with height. The breadth of four events
decreases with height. When all nine events are considered together,
the transient breadth with height is fitted with an expression h
varies as R exp 0.48 with large scatter. In addition, measurements of
the total observed loop length of the nine transients show that this
length L varies as R exp 1.30. Both of these results are contrary
to the predictions of one model of loop expulsion as a result of an
assumed azimuthal magnetic field gradient. Finally, when combined with
the facts that looplike mass ejections are usually associated with
the occurrence of eruptive prominences, and that such mass ejections
are generally accelerated through the corona, it is found that the
observed variation of transient breadth with height contradicts some
characteristics of self-similar fluid flow which have been ascribed
to mass-ejection transients.
Title: The Broadening of Looplike Solar Coronal Transients
Authors: MacQueen, R. M.; Cole, D.
Bibcode: 1985BAAS...17..636M
Altcode:
No abstract at ADS
Title: Coronal Mass Ejections - Acceleration and Surface Associations
Authors: MacQueen, R. M.
Bibcode: 1985SoPh...95..359M
Altcode:
The fact that eruptive-prominence associated coronal mass ejection
events may be accelerated over significant heights and times in the
corona complicates the determination of possible surface or low coronal
associations. A specific example of one such eruptive-prominence
associated event, that observed in both the inner and outer solar
corona on August 5, 1980, is used to illustrate the magnitude of
the uncertainty of determining an onset time of the ejection. It is
noted that such uncertainties may influence statistically-determined
associations.
Title: Reply
Authors: Sime, D. G.; MacQueen, R. M.; Hundhausen, A. J.
Bibcode: 1985JGR....90..563S
Altcode:
No abstract at ADS
Title: Recent Interpretation of Coronal Transient Results
Authors: MacQueen, R. M.
Bibcode: 1985spit.conf..969M
Altcode:
No abstract at ADS
Title: Coronal Mass Ejection Transients
Authors: MacQueen, R. M.
Bibcode: 1985spit.conf...89M
Altcode:
No abstract at ADS
Title: Density distribution in looplike coronal transients: A
comparison of observations and a theoretical model
Authors: Sime, D. G.; MacQueen, R. M.; Hundhausen, A. J.
Bibcode: 1984JGR....89.2113S
Altcode:
Examination of the intensity changes in five outer coronal ``looplike''
transients observed by the Skylab coronagraph shows general tendencies
(1) greatest concentration of material at the flanks rather than at
the tops of the bright loops that characterize these transients, (2)
presence of a large region of depleted density within these loops, and
(3) developement of bright legs that contain most of the material in
the transient and that display very little lateral motion as the top of
the bright loop moves radially outward through the outer corona. These
properties of looplike coronal transients provide useful constraints on
theoretical models of this phenomenon. In particular, direct comparison
of the observed density distributions with those predicted by models
of compressional waves initiated by an impulsive energy release in
the low corona are a necessary test of these models. These models
predict a maximum enhancement at the top of the loop, rather than at
the flanks and ``legs'' that move laterally with a significant fraction
of the propagation speed of the loop top, in conflict with the observed
tendencies. If the observed loops are taken to have the geometry assumed
in the compressive wave models (``toroidal symmetry'' about a rotation
axis passing through the center of the sun), the predicted density
enhancements are several times larger than those inferred from the
observations. Agreement cannot be achieved without use of a geometry
which conflicts with that used for the model calculations.
Title: The Kinematics of Solar Inner Coronal Transients
Authors: MacQueen, R. M.; Fisher, R. R.
Bibcode: 1983SoPh...89...89M
Altcode:
The kinematic properties of a dozen `loop-like' coronal transients have
been examined over the range 1.2-2.4 R⊙ from Sun center. Values and
trends of transient geometry, including radial height, lateral width
at maximum extent, distance from loop top to height of maximum width,
and lateral width at a fixed height above the instrument occulting
disk at 1.2 R⊙, are given. Radial and lateral speeds of expansion
are tabulated, and range from 60-900 km s-1, and 10-500
km s-1, respectively. Flare-associated events are found to
exhibit the highest speeds, and show little acceleration with height;
on the other hand, eruptiveassociated events exhibit large accelerations
(some in excess of 50 m s-2). This clear discrimination
between flare and eruptive-associated events suggests that two different
physical processes are present; it is suggested that flare-associated
events result from an impulsive, localized input to the corona. On
the other hand, accelerated, eruptive-associated events are subjected
to appreciable net forces over radial heights of one solar radius
(or more) above the solar limb. It is conjectured that the pressure
gradient forces responsible for the generation of the solar wind may
play an important role in accelerating these latter events.
Title: The excitation of type II radio bursts in the corona
Authors: Wagner, W. J.; MacQueen, R. M.
Bibcode: 1983A&A...120..136W
Altcode:
Simultaneous radioheliograph and orbital coronagraph observations
of coronal transient activity shows metric type II radio emission
originating early in the event, well below the visible white light
transient. The authors suggest that the shock which excites the type
II emission is independent of the transient, in the sense that it is
initiated in the low corona (probably in association with a flare)
and travels through the already-existing transient disturbance with
a propagation speed significantly greater than that of the front
edge of the transient itself. Radio emission then results when the
flare shock overtakes, first, the region of principal density pile-up
along the sides of the expanding transient and only later the top of
the transient.
Title: Detection of Slow, Bright Coronal Transients
Authors: Garcia, C.; Fisher, R.; MacQueen, R.
Bibcode: 1983BAAS...15..706G
Altcode:
No abstract at ADS
Title: Kinematics of Solar Coronal Transients
Authors: MacQueen, R. M.; Fisher, R. R.
Bibcode: 1983BAAS...15..707M
Altcode:
No abstract at ADS
Title: Density Distribution in Loop-Like Coronal Transients: A
Comparison of Observations and a Theoretical Model
Authors: Sime, D. G.; MacQueen, R. M.; Hundhausen, A. J.
Bibcode: 1983BAAS...15..707S
Altcode:
No abstract at ADS
Title: The Properties of Coronal Voids
Authors: MacQueen, R. M.; Sime, D. G.; Picat, J. -P.
Bibcode: 1983SoPh...83..103M
Altcode:
Observations of the outer solar corona obtained by the High Altitude
Observatory's coronagraph aboard Skylab reveal the presence of dark,
ray-like structures in the corona. A systematic identification of these
voids, which exist for periods of about 24 hr, is presented and their
existence as a coronal phenomenon, as opposed to a subtle photographic
effect, verified. Photometric analysis indicates that these features
represent reductions in the coronal radiance on the order of 5% - or
about 2-3 × 10−10B⊙ at 3 R⊙. The
use of a previously determined model of the electron component of the
corona permits specification of the electron density in the voids
over the range 2.5-4.5 R⊙. In spite of the inevitable
uncertainties regarding their longitudinal extent, we estimate that
their electron density is comparable to, or less than, that in coronal
holes at similar heights. Projection of the phenomena onto synoptic
surface maps indicates a close relationship with filaments and neutral
lines; a potentially significant temporal correlation between the void
formation and that of the underlying prominence is noted. The spatial
and temporal resolution of the data set places stringent restrictions on
any model which may be used to infer the physical processes of formation
or decay of voids; several possibilities are suggested which involve
either changes in the coronal base temperature or the magnetic flux.
Title: Solar wind five. Proceedings of a conference held in Woodstock,
Vermont, November 1 - 5, 1982.
Authors: Neugebauer, M.; Hollweg, J. V.; Barnes, A.; MacQueen, R.;
Rosner, R.; Eddy, J. A.
Bibcode: 1983swfp.book.....N
Altcode:
No abstract at ADS
Title: The Spacelab Lyman-Alpha and White Light Coronagraphs Program
Authors: Kohl, J. L.; Withbroe, G. L.; Weiser, H.; MacQueen, R. M.;
Munro, R. H.
Bibcode: 1981SSRv...29..419K
Altcode:
The Harvard-Smithsonian Center for Astrophysics and the High Altitude
Observatory have defined a joint coronagraphs experiment for a
future Spacelab mission. The instrumentation package would include an
ultraviolet light coronagraph to measure the intensity and profiles of
spectral lines formed between 1.2 and 8 solar radii from Sun center and
a white light coronagraph to measure the intensity and polarization
of visible light. The overall goals of the joint program are to use
new coronal plasma diagnostic techniques to understand the physical
processes and mechanisms operating in the solar corona, to understand
the acceleration of high-speed and low-speed solar wind streams and to
extrapolate this knowledge to other stars in order to help understand
the physics of stellar coronae and stellar mass loss.
Title: The Evolution of a Coronal Streamer and the Photospheric
Magnetic Field
Authors: Poland, A. I.; MacQueen, R. M.
Bibcode: 1981SoPh...71..361P
Altcode:
A large equatorial coronal streamer observed in the outer corona
(3R⊙) grew in brightness and size during successive limb
passages between October 6, 1973 and January 10, 1974 (solar rotations
1606-1611). Unlike previous studies of streamers and their photospheric
associations, no definite surface feature could be identified in the
present case. This suggests that the streamer is associated with the
large scale photospheric magnetic field. Comparison of the streamer
growth with observed underlying photospheric magnetic flux changes
indicated that as the streamer increased in brightness, areal extent,
and density, the photospheric magnetic flux decreased. Three possible
explanations for the streamer's growth are presented; the conceptually
simplest being that the decrease in photospheric field results in an
opening of the flux tubes under the streamer which permits an increased
mass flux through the streamer.
Title: The Pinhole/Occulter Facility
Authors: Hudson, H. S.; Kohl, J. L.; Lin, R. P.; MacQueen, R. M.;
Tandberg-Hanssen, E.; Pabbs, J. R.
Bibcode: 1981pof..rept.....H
Altcode:
A large occulting system in space can be used for high resolution
X-ray observations and for large aperture coronagraphic observations in
visible and UV light. The X-ray observations can combine high angular
resolution in hand (10 keV) X-radiation with the high sensitivity
of a multiple pinhole camera, and can permit sensitive observations
of bremsstrahlung from nonthermal particles in the corona. The
large aperture coronagraphs have two major advantages: high angular
resolution and good photon collection. This will permit observations
of small scale structures in the corona for the first time and will
give sufficient counting rates above the coronal background rates
for sensitive diagnostic analysis of intensities and line profiles
for coronal structures in the solar wind acceleration region. The
technical basis for performing observations with a large occulting
system in these three wavelength ranges is described as well as a
pinhole/occulter facility presently being considered for Spacelab. Some
indications about future developments are included.
Title: New Mauna Loa coronagraph systems
Authors: Fisher, R. R.; Lee, R. H.; MacQueen, R. M.; Poland, A. I.
Bibcode: 1981ApOpt..20.1094F
Altcode:
A new set of instruments, consisting of two coronagraph systems,
has been installed and is operating at the Mauna Loa Observing
Station, Hawaii. The instruments are the 23-cm objective Mark III
K-coronameter (K-III) system, a photoelectric instrument used to
observe the inner solar corona from 1.2 R0 to 2.2 R0 and the 12.5-cm
objective Prominence Monitor system used for the detection of H-alpha
limb activity. New features of the K-coronameter system include the
use of achromatic wave plates for wide bandpass operation and linear
diode array detectors. Raster scans of the coronal image are obtained
in 1.5 min for a critical sampling scheme of 20-sec of arc resolution
(10 x 10-sec of arc pixels) in the coronal pB image. This represents
a 350 information gain factor for each detection channel when compared
with the previous Mauna Loa K-coronameters.
Title: The high altitude observatory of the national center for
atmospheric research Boulder, Colorado
Authors: MacQueen, R. M.
Bibcode: 1980SoPh...68..411M
Altcode:
The High Altitude Observatory attempts to carry out a balanced program
of theoretical and experimental research in solar, solar-terrestrial,
and stellar-related physics. The scientific efforts are carried
out within a sectional structure including the major areas of Solar
Atmosphere and Magnetic Fields, Coronal/Interplanetary Physics, and
Solar Variability. As one division of a National Center, the Observatory
attempts to provide leadership through operation and sponsorship of
seminars on specialized topics and organization of workshops to exploit
data collections. In addition to the examples given, the Observatory,
under NASA sponsorship, has organized a workshop series on solar
flares, a central theme of which was the interpretation of Skylab
results. This effort has resulted in the publication of a volume Solar
Flares, edited by P. Sturrock, Colorado Associated University Press,
1979. Through these efforts, and the participation of individual staff
members on advisory committees and working groups within the national
and international framework, the Observatory continues to play a role
in the guidance of research in solar and related physics.
Title: The Orientation of Pre-Transient Coronal Magnetic Fields
Authors: Trottet, G.; MacQueen, R. M.
Bibcode: 1980SoPh...68..177T
Altcode:
Loop-like white light coronal transients are generally believed to
be nearly planar sheets which are thin compared to the loop extent;
however, this picture may be questioned since virtually no observations
(of the more than 100 transient events observed during 1973-74 Skylab
period) show such loops edge-on. From the group of transient events
studied by Munro etal. (1979) for which definite surface associations
exist, we find loop transients are strongly correlated with filament
regions where the filament axis was oriented north-south. From
direct soft X-ray observations of an expanding arch, the possible
identification of the soft X-ray signature of footpoints of transient
loops, and monochramatic observations of low coronal loops, we infer
that loop-like coronal transients have their origin in low-lying coronal
loops nearly co-planar with the north-south aligned filament axis. The
situation with respect to non-loop events is less clear; such events
apparently often arise from more complex filament geometries. Possible
reasons for the preference of transients to arise from north-south
filament-oriented regions are discussed.
Title: Measurements of coronal kinetic temperatures from 1.5 to 3
solar radii
Authors: Kohl, J. L.; Weiser, H.; Withbroe, G. L.; Noyes, R. W.;
Parkinson, W. H.; Reeves, E. M.; Munro, R. H.; MacQueen, R. M.
Bibcode: 1980ApJ...241L.117K
Altcode:
A rocket-borne Lyman-alpha coronagraph has been used to make the first
measurements of the spectral line profile of resonantly scattered
hydrogen Lyman-alpha coronal radiation between 1.5 and 3 solar
radii. These data provide, for the first time, direct measurements of
coronal temperatures above 1.5 solar radii. Data were obtained in a
coronal hole, quiet region, and streamer. The widths of the profiles
from the quiet region decrease with height and correspond to a steady
decrease in hydrogen kinetic temperature, with increasing radius, from
about 2.5 million K at r = 2 solar radii to about 1 million K at r =
9 solar radii. In the coronal hole the measured line widths indicate
a kinetic temperature of 1.8 million K at r = 2.5 solar radii.
Title: The Spacelab Lyman-Alpha and White-Light Coronagraphs Program
Authors: Kohl, J. L.; MacQueen, R. W.; Withbroe, G. L.; Munro, R.;
Weiser, H.
Bibcode: 1980BAAS...12..793K
Altcode:
No abstract at ADS
Title: Coronal Transients: A Summary
Authors: MacQueen, R. M.
Bibcode: 1980RSPTA.297..605M
Altcode: 1980RSLPT.297..605M
Observations with orbiting coronagraphs have illuminated the role
of coronal mass ejections in solar activity, and raised a number
of questions concerning their origin, the nature of the forces
driving the coronal material, and their signature in interplanetary
space. Current models of the ejection process -- including
propagation of loops as a result of azimuthal field gradients,
ring currents or a build-up of magnetic pressure from below -- are
summarized, as are magnetohydrodynamic codes intended to stimulate
transient conditions. Metric radio observations, can, in principle,
distinguish the relative role of the magnetic field in the ejection
process; observations to date are surveyed. It is concluded that at
present, no compelling evidence is available to distinguish between
transient driving mechanisms, but future observations of the corona
and interplanetary medium may resolve the present ambiguity.
Title: The High Altitude Observatory coronagraph/polarimeter on the
Solar Maximum Mission.
Authors: MacQueen, R. M.; Csoeke-Poeckh, A.; Hildner, E.; House, L.;
Reynolds, R.; Stanger, A.; Tepoel, H.; Wagner, W.
Bibcode: 1980SoPh...65...91M
Altcode:
The High Altitude Observatory Coronagraph/Polarimeter, to be flown
on the National Aeronautics and Space Administration's Solar Maximum
Mission satellite, is designed to produce images of the solar corona in
seven wavelength bands in the visible spectral range. The spectral bands
have been chosen to specifically exclude or include `chromospheric'
spectral lines, so as to allow discrimination between ejecta at high
(coronal) and low (chromospheric) temperatures, respectively. In
addition, the instrument features spectral filters designed to permit
an accurate color separation of the F and K coronal components, and a
narrow band (5.5 Å) filter to observe the radiance and polarization
of the Fe XIV 5303 Å line. The effective system resolution is better
than 10 arc sec and the instrument images a selected quadrant (or
smaller field) on an SEC vidicon detector. The total height range
that may be recorded encompasses 1.6 to more than 6.0R⊙
(from Sun center). The instrument is pointed independently of the
SMM spacecraft, and its functions are controlled through the use
of a program resident within the onboard spacecraft computer. Major
experimental goals include: (a) Observation of the role of the corona
in the flare process and of the ejecta from the flare site and the
overlying corona; (b) the study of the direction of magnetic fields in
stable coronal forms, and, perhaps, ejecta; and (c) examination of the
evolution of the solar corona near the period of solar maximum activity.
Title: National-Center Atmospheric Research
Authors: MacQueen, R. M.
Bibcode: 1980BAAS...12..279M
Altcode:
No abstract at ADS
Title: Skylab observations of the coronal structure overlying a type
III producing active region.
Authors: Pick, M.; Trottet, G.; MacQueen, R. M.
Bibcode: 1979SoPh...63..369P
Altcode:
The coronal structure overlying, and presumably associated with, an
isolated active region, McMath 12686, is identified during its west
limb passage 15-17 January 1974. The region had a `flaring site' on
its border close to a plage filament and exhibited various forms of
activity, including type III burst production, during the three days
of study. Although the coronal structure overlying the region was of
small scale, its estimated electron density was ∼10 × that of the
background corona, and it varied in density by a factor of two over
a time scale of hours. Some implications of such a structure on the
interpretation of type III emission are considered.
Title: Lyman-α and White Light Observations of the Outer Solar
Corona.
Authors: Munro, R. H.; Kohl, J. L.; MacQueen, R. M.; Noyes, R. W.;
Parkinson, W. H.; Weiser, H.; Withbroe, G. L.
Bibcode: 1979BAAS...11..398M
Altcode:
No abstract at ADS
Title: The association of coronal mass ejection transients with
other forms of solar activity.
Authors: Munro, R. H.; Gosling, J. T.; Hildner, E.; MacQueen, R. M.;
Poland, A. I.; Ross, C. L.
Bibcode: 1979SoPh...61..201M
Altcode:
Coronal mass ejection transients observed with the white light
coronagraph on Skylab are found to be associated with several other
forms of solar activity. There is a strong correlation between
such mass ejection transients and chromospheric Hα activity, with
three-quarters of the transients apparently originating in or near
active regions. We infer that 40% of transients are associated with
flares, 50% are associated with eruptive prominences solely (without
flares), and more than 70% are associated with eruptive prominences or
filament disappearances (with or without flares). Nine of ten flares
which displayed apparent mass ejections of Hα-emitting material from
the flare site could be associated with coronal transients. Within
each class of activity, the more energetic events are more likely to
be associated with an observable mass ejection.
Title: Multicolor imaging and photopolarimetry: Disk features,
K and F coronas, zodiacal light
Authors: Weinberg, J. L.; MacQueen, R. M.
Bibcode: 1978clus.nasa..143W
Altcode:
The unique vantage points and viewing geometries afforded by a close-in
solar probe are briefly examined with regard to line and continuum
measurements of features on the solar disk, the K and F coronas, and
the zodiacal light. Common instrument and observing requirements are
identified, suggesting that a single instrument could provide much of
the necessary observational data on these phenomena.
Title: Temporal evolution of the equatorial K-corona.
Authors: MacQueen, R. M.; Poland, A. I.
Bibcode: 1977SoPh...55..143M
Altcode:
Observations of the equatorialK-coronal radiance at 2.5R⊙
from Sun center and its variation with time, on a daily basis,
during the Skylab mission (May 1973-February 1974) are presented. The
observations are subdivided into three periods, each characterized
by a different variation of the radiance pattern with time. During
the initial period, encompassing two solar rotations, there are
several data gaps, but the radiance pattern shows a more or less
smooth variation with time; however, during the second period (also
about two solar rotations duration) the radiance signal is neither
persistent on the short term nor recurrent from one limb passage to
the next. Finally, during the last period, of five solar rotations
duration, the radiance signal exhibits an orderly periodic behavior
of increasing intensity. These results are interpreted as indicating
a general simplification of the coronal magnetic field through the
mission and, in comparison with harmonic analysis of the surface
magnetic field (Levine, 1977), as indicating a rapid response of
equatorial outer coronal structures to abrupt changes in the global
surface field structure.
Title: Radiance calibration of the High Altitude Observatory
white-light coronagraph on Skylab.
Authors: Poland, A. I.; Gosling, J. T.; MacQueen, R. M.; Munro, R. H.
Bibcode: 1977ApOpt..16..926P
Altcode:
The processing of over 35,000 photographs of the solar corona obtained
by the white-light coronograph on Skylab is described. Calibration of
the vast amount of data was complicated by temporal effects of radiation
fog and latent image loss. These effects were compensated by imaging
a calibration step wedge on each data frame. Absolute calibration of
the wedge was accomplished through comparison with a set of previously
calibrated glass opal filters. Analysis employed average characteristic
curves derived from measurements of step wedges from many frames within
a given camera half-load. The net absolute accuracy of a given radiance
measurement is estimated to be 20%.
Title: Measurement of stray radiance in the High Altitude
Observatory's Skylab coronagraph.
Authors: Csoeke-Poeckh, A.; MacQueen, R. M.; Poland, A. I.
Bibcode: 1977ApOpt..16..931C
Altcode:
The paper outlines two techniques used for determining the instrumental
stray radiance from orbital results obtained with the Skylab white light
coronagraph. The first technique employs images of the lunar disk made
near the time of solar eclipse to compare the apparent contrasts of
maria and highlands recorded by the coronograph with those of previous
studies and then determine the magnitude of the stray radiance and its
variation along a radius. The second method determines the azimuthal
variation of the stray radiance by measuring the change in the net
radiance of a point in the coronal images as the image is rotated.
Title: The Background Corona Near Solar Minimum.
Authors: Saito, K.; Poland, A.; Munro, R.; MacQueen, R.
Bibcode: 1977BAAS....9Q.371S
Altcode:
No abstract at ADS
Title: White light and radio studies of the coronal transient of 14
15 September 1973
Authors: Smerd, S. F.; Dulk, G. A.; MacQueen, R. M.; Gosling,
J. T.; Magun, A.; Stewart, R. T.; Sheridan, K. V.; Robinson, R. D.;
Jacques, S.
Bibcode: 1976SoPh...49..369S
Altcode:
Observations of a coronal transient event were obtained in
white light by the Skylab coronagraph and at metric wavelengths
by the radioheliograph and spectrograph at Culgoora and the
spectrograph-interferometer at Boulder. The continuum radio burst was
found to originate above the outward-moving white light loop - a region
of compressed material headed by a bow wave. The computed density
in the region of radio emission, based on either gyro-synchrotron or
harmonic plasma radiation mechanisms, was approximately 10 times the
ambient coronal density; this is compatible with the density deduced
from the white light observations. The magnetic energy density derived
from the radio observations was greater than 10 times the thermal
energy density, marginally larger than the kinetic energy density in
the fastest moving portion of the transient, and considerably larger
in most other regions. The ambient medium, the white light front, the
compression region, the loop, and the slower, massive flow of material
behind are each examined. It is found that the plasma was magnetically
controlled throughout, and that magnetic forces provided the principal
mechanism for acceleration of the transient material from the Sun.
Title: White Light and Radio Studies of the Coronal Transient of
14-15 September 1973. I: Material Motions and Magnetic Field
Authors: Dulk, G. A.; Jacques, S.; Smerd, S. F.; MacQueen, R. M.;
Gosling, J. T.; Steward, R. T.; Sheridan, K. V.; Robinson, R. D.;
Magun, A.
Bibcode: 1976SoPh...49..369D
Altcode:
Observations of a coronal transient event were obtained in white
light by the Skylab coronagraph and at metric wavelengths by the
radioheliograph and spectrograph at Culgoora, Australia, and the
spectrograph-interferometer at Boulder, Colo. The continuum radio burst
was found to originate above the outward-moving white-light loop, a
region of compressed material headed by a bow wave. The computed density
in the region of radio emission, based on either gyrosynchrotron or
harmonic plasma radiation mechanisms, was approximately 10 times the
ambient coronal density; this is compatible with the density deduced
from the white-light observations. The magnetic-energy density derived
from the radio observations was greater than 10 times the thermal
energy density, marginally larger than the kinetic energy density in
the fastest-moving portion of the transient, and considerably larger
in most other regions. The ambient medium, the white-light front, the
compression region, the loop, and the slower massive flow of material
behind are each examined. It is found that the plasma was magnetically
controlled throughout and that magnetic forces provided the principal
mechanism for acceleration of the transient material from the sun.
Title: The speeds of coronal mass ejection events.
Authors: Gosling, J. T.; Hildner, E.; MacQueen, R. M.; Munro, R. H.;
Poland, A. I.; Ross, C. L.
Bibcode: 1976SoPh...48..389G
Altcode:
The outward speeds of mass ejection events observed with the
white light coronagraph experiment on Skylab varied over a range
extending from less than 100 km s−1 to greater than
1200 km s−1. For all events the average speed within
the field of view of the experiment (1.75 to 6 solar radii) was 470
km s−1. Typically, flare associated events (Importance
1 or greater) traveled faster (775 km s−1) than events
associated with eruptive prominences (330 km s−1); no
flare associated event had a speed less than 360 km s−1,
and only one eruptive prominence associated event had a speed greater
than 600 km s−1. Speeds versus height profiles for a
limited number of events indicate that the leading edges of the ejecta
move outward with constant or increasing speeds.
Title: Initial Results from the High Altitude Observatory White
Light Coronagraph on Skylab - A Progress Report
Authors: MacQueen, R. M.; Gosling, J. T.; Hildner, E.; Munro, R. H.;
Poland, A. I.; Ross, C. L.
Bibcode: 1976RSPTA.281..405M
Altcode: 1976RSLPT.281..405M
The frequent, periodic observations by the white light coronagraph
allow an examination of coronal variations over a broad range of
temporal scales. Examples of the slowest and most rapid variations
are presented. An example of extremely slow coronal variations is the
gradual evolution - to a large equatorial streamer - in association
with a marked decrease in solar activity, as the total magnetic flux
in one hemisphere decreased. Another example is given of a long-lived
quasi-stable coronal streamer, apparently associated with a stable
filament channel; comparison of this streamer with coronal potential
magnetic field computations show little correlation. The remainder
of the paper summarizes some results on coronal transients - the most
rapid variations observed. Characteristic mass and energies involved
in mass ejection transients, their temporal and spatial distributions,
their associations with surface phenomena and possible interplanetary
signatures, and finally their role in coronal evolution are briefly
noted.
Title: Frequency of coronal transients and solar activity.
Authors: Hildner, E.; Gosling, J. T.; MacQueen, R. M.; Munro, R. H.;
Poland, A. I.; Ross, C. L.
Bibcode: 1976SoPh...48..127H
Altcode:
The High Altitude Observatory's white light coronagraph aboard Skylab
observed some 110 coronal transients - rapid changes in appearance
of the corona - during its 227 days of operation. The longitudes
of the origins of these transients were not distributed uniformly
around the solar surface (51 of the 100 events observed in seven
solar rotations arose from a single quadrant of longitude). Further,
the frequency of transient production from each segment of the solar
surface was well correlated with the sunspot number and Ca II plage
(area × brightness) index in the segment, rotation by rotation. This
correlation implies that transients occur more often above strong
photospheric and chromospheric magnetic fields, that is, in regions
where the coronal magnetic field is stronger and, perhaps, more
variable. This pattern of occurrence is consistent with our belief
that the forces propelling transient material outward are, primarily,
magnetic. A quantitative relation between transient production from
an area and the Zürich sunspot number appropriate to that area is
derived, and we speculate that the relation is independent of phase
in the solar activity cycle. If true, the Sun may give rise to as many
as 100 white light coronal transients per month at solar cycle maximum.
Title: Equatorial Electron Coronal Variations
Authors: MacQueen, R.
Bibcode: 1976BAAS....8..369M
Altcode:
No abstract at ADS
Title: The Speeds of Coronal Mass Ejection Events
Authors: Hildner, E.; MacQueen, R. M.; Munro, R. H.; Poland, A. I.;
Ross, C. L.; Gosling, J. T.
Bibcode: 1976BAAS....8R.368H
Altcode:
No abstract at ADS
Title: Movie of Comet Kohoutek (1973f) as Observed Near Minimum
Elongation by the Hao Coronagraph Aboard SKYLAB
Authors: Hildner, E.; Gosling, J. T.; MacQueen, R. M.; Munro, R. H.;
Poland, A. I.; Ross, C. L.
Bibcode: 1976NASSP.393..124H
Altcode: 1976IAUCo..25..124H
No abstract at ADS
Title: Radiation and structure of the solar atmosphere (Radiation
et structure de l'atmosphère solaire).
Authors: Giovanelli, R. G.; Mein, P.; Bappu, M. K. V.; Jordan, C.;
MacQueen, R. M.
Bibcode: 1976IAUTA..16b..55G
Altcode:
No abstract at ADS
Title: Solar activity (Activité solaire).
Authors: Newkirk, G.; Dunn, R. B.; Mehltretter, P.; MacQueen, R.;
Bonnet, R. M.; White, O. R.; Fokker, A. D.; Zwaan, C.; Bruzek, A.;
Durrant, C.; Grossmann-Doerth, U.; Mehltretter, J. P.; Svestka, Z.;
de Feiter, L. D.; Tandberg-Hanssen, E.; Howard, R.; Stix, M.; Pneuman,
G. W.; Hundhausen, A. J.; Sawyer, C.; Simon, P.
Bibcode: 1976IAUTA..16b..13N
Altcode:
No abstract at ADS
Title: A search for forward scattering of sunlight from lunar
libration clouds
Authors: Munro, R. H.; Gosling, J. T.; Hildner, E.; MacQueen, R. M.;
Poland, A. I.; Ross, C. L.; Hopfield, A.
Bibcode: 1975P&SS...23.1313M
Altcode:
An attempt to determine the radiance of forward scattered sunlight
from particles in lunar libration regions was made with the white light
coronagraph on Skylab. The libration regions could not be distinguished
against the solar K + F coronal background; an upper limit to the
libration cloud radiance is determined to be 2·5 × 10 -11B
⊚, where B ⊚ is the mean radiance of the
solar disk. Employing a model of the particle composition and size
distribution which has been proposed for the interplanetary medium,
we determine upper limits for the density enhancements in the libration
region from the upper limit of the forward scattered radiance presented
herein. Similarly, the actual spatial density enhancement is calculated
using the earlier observations of the libration region backscattered
radiance (Roach, 1975). Enhancements of a factor of 10 2-10
3 are thus determined, depending upon material composition
and size distribution used. By combining the forward and backscatter
observations, it is possible to eliminate from consideration clouds
whose power law particle size distribution exponent k is 2·5
and complex index of refraction m is 1·33-0.05 i and 1·50-0.05 i
(i.e. absorbing ice and quartz particles, respectively). Finally, the
radiance contrast of a possible model libration cloud is calculated with
respect to the K- and F-corona/zodiaal light background and is shown
to be a maximum in the vicinity of solar elongation angle ∼30 deg.
Title: The Large Coronal Transient of 10 June 1973. I: Observational
Description
Authors: Hildner, E.; Gosling, J. T.; MacQueen, R. M.; Munro, R. H.;
Poland, A. I.; Ross, C. L.
Bibcode: 1975SoPh...42..163H
Altcode:
During the 8.5 month flight of the High Altitude Observatory's white
light coronagraph on board Skylab, over 100 coronal transients were
observed. In this paper we present a description of one well observed
loop transient, that of 10 June 1973. The transient apparently resulted
from the eruption of a quiescent prominence on the limb; the emergence
of a new, bipolar active region near the prominence may have caused
the eruptior. The transient's leading edge rose from 3.6 to 5.0
solar radii (R⊙) from Sun center at approximately 500 km
s−1 during the 32 min of coronagraph observations. Material
in a pre-existing streamer was swept away by the transient, causing
the streamer to disappear. The mass ejected into the corona above a
projected height of 2 R⊙ was ≈ 5.4 × 1015 g,
the potential energy associated with the ejected transient material was
⩾7.0 × 1030 erg, and the kinetic energy of the ejected
material is estimated as 1.7 × 1030 erg. The 10 June 1973
transient was, in most respects, typical of other loop transients
observed by Skylab.
Title: White Light and Radio Studies of the Coronal Transient of
14-15 September 1973 I. Observations and Emission Mechanisms
Authors: Robinson, R.; MacQueen, R. M.
Bibcode: 1975BAAS....7..348R
Altcode:
No abstract at ADS
Title: Direct Observations of a Flare Related Coronal and Solar
Wind Disturbance
Authors: Gosling, J. T.; Hildner, E.; MacQueen, R. M.; Munro, R. H.;
Poland, A. I.; Ross, C. L.
Bibcode: 1975SoPh...40..439G
Altcode:
Numerous mass ejections from the Sun have been detected with orbiting
coronagraphs. Here for the first time we document and discuss the direct
association of a coronagraph observed mass ejection, which followed a
2B flare, with a large interplanetary shock wave disturbance observed
at 1 AU. Estimates of the mass (2.4 × 1016 g) and energy
content (1.1 × 1032 erg) of the coronal disturbance are
in reasonably good agreement with estimates of the mass and energy
content of the solar wind disturbance at 1 AU. The energy estimates as
well as the transit time of the disturbance are also in good agreement
with numerical models of shock wave propagation in the solar wind.
Title: Photography of comet Kohoutek by Skylab white light
coronagraph.
Authors: MacQueen, R. M.; Gosling, J. T.; Hildner, E.; Munro, R. H.;
Poland, A. I.; Ross, C. L.; Keller, H. U.; Schmidt, H. U.
Bibcode: 1975NASSP.355...19M
Altcode: 1975coko.conf...19M
No abstract at ADS
Title: Mass ejections from the Sun: A view from Skylab
Authors: Gosling, J. T.; Hildner, E.; MacQueen, R. M.; Munro, R. H.;
Poland, A. I.; Ross, C. L.
Bibcode: 1974JGR....79.4581G
Altcode:
More than 30 instances of sudden mass ejections from the sun were
observed with the white light coronagraph experiment aboard Skylab
during the first 118 days of the mission. Typically, these ejections
appear as large magnetic loops rooted at the sun, yet expanding
outward through the solar corona at speeds of the order of 400 km
s-1. The loops always appear to retain their magnetic
connection to the sun. Eighteen of these ejections were associated
with active and eruptive prominences and surges; only three ejections
appear to have been flare initiated. Associations with ground-detected
metric wavelength type 2 and 4 radio bursts occur for about 30% of these
events; however, ground-detected type 2 and 4 radio bursts originating
near the limb are almost invariably accompanied by coronagraph-observed
ejections. Pressure or MHD waves run out ahead of the transient material
ejecta; at times these waves can be detected by their effects on nearby
coronal structures. For one event, that of August 10, 1973, we make
the following estimates: (1) mass content, 4 × 1015 grams;
(2) mass flow rate, 1.1 × 1012 grams s-1 (3)
energy content, 8.4 × 1030 ergs; and (4) energy flow rate,
7.7 × 1026 ergs s-1. Locally, this represents
a significant mass and energy input to the solar wind; we suggest that
the ejections are the coronal counterparts of nonrecurrent (including
shocks) solar wind disturbances detected near the orbit of the earth.
Title: Observed streamer curvature in the outer solar corona
Authors: Wilson, D. C.; MacQueen, R. M.
Bibcode: 1974JGR....79.4575W
Altcode:
The first observations of coronal streamers to an elongation angle
of 12.5° (50 Rs from sun center) were taken aboard the
Apollo 15 command module in lunar orbit. Streamer curvature in both
heliocentric latitude and heliocentric longitude may be determined from
the positions of three curved streamers. This curvature is interpreted
by assuming that it is not transient and that streamers trace flow from
a stationary position on the solar surface. The azimuthal curvature
is explained by corotation of streamer material with the sun out to
approximately 25 Rs, followed by a constant radial velocity
of 275 km/s and force free flow to 60 Rs. The curvature
toward the solar equator implies a meridional flow of 45 ±15 km/s
between 50 and 60 Rs. If constant angular momentum is
assumed beyond 60 Rs, the resultant azimuthal and meridional
velocities are consistent with the solar wind observed at 1 AU. The
radial velocity, including a small expected acceleration between 60
Rs and 1 AU, is typical of slow-speed solar wind. Streamer
curvature is compared with interplanetary magnetic field models.
Title: The coronal radiance in the intermediate infrared.
Authors: Mankin, W. G.; MacQueen, R. M.; Lee, R. H.
Bibcode: 1974A&A....31...17M
Altcode:
Summary. An observed value of the spectral mean of the coronal radiance
in the intermediate infrared U.5-13 of 9+5 x - - at 4 R0 is presented,
with the observed change in radiance with elongation angle over the
range 3.5- 12.5 R0. The observations are consistent with the model of
silicate emission proposed by Kaiser (1970), but a two component model
is required to reconcile these observations and the measurements by
Peterson (1971) at wavelengths of 2.2 and less. Key words: F corona -
thermal emission - interplanetary dust
Title: The High Altitude Observatory White Light Coronagraph
Experiment
Authors: MacQueen, R. M.; Gosling, J. T.; Hildner, E.; Munro, R. H.;
Poland, A. I.; Ross, C. L.
Bibcode: 1974IAUS...57..505M
Altcode:
No abstract at ADS
Title: Airborne far infrared solar spectroscopy
Authors: Mankin, W. G.; Eddy, J. A.; Lee, R. H.; MacQueen, R. M.
Bibcode: 1974SPIE...44..133M
Altcode:
A description is provided of an instrument which has been developed
to measure the far infrared brightness temperature of the sun. The
instrument consists of a 20 cm aperture photoguided telescope, a high
resolution Michelson interferometer, a helium cooled gallium doped
germanium bolometer, and two blackbodies for radiometric reference. The
instrument along with its supporting electronic equipment, including
a minicomputer, is mounted aboard a Sabreliner, which carries it to
an altitude of 12 km for observations above the tropopause.
Title: The High Altitude Observatory white light coronagraph
Authors: MacQueen, R. M.; Gosling, J. T.; Hildner, E.; Munro, R. H.;
Poland, A. I.; Ross, C. L.
Bibcode: 1974SPIE...44..207M
Altcode:
Most of the instruments of the Apollo Telescope Mount are
satellite-borne because they observe in regions of the electromagnetic
spectrum where the telluric atmosphere is opaque. For the coronagraph of
the High Altitude Observatory, observing in visible light, this is not
so. The structure of the solar corona is obscured from ground-based
observations by scattered light in the earth's atmosphere, and
observations from space are required to reduce this scattered light
to a level which is negligible with respect to the brightness of the
outer solar corona.
Title: The High Altitude Observatory white-light coronagraph
experiment of Skylab.
Authors: MacQueen, R. M.
Bibcode: 1974JOSA...64..523M
Altcode:
No abstract at ADS
Title: The Outer Solar Corona as Observed from Skylab: Preliminary
Results
Authors: MacQueen, R. M.; Eddy, J. A.; Gosling, J. T.; Hildner, E.;
Munro, R. H.; Newkirk, G. A., Jr.; Poland, A. I.; Ross, C. L.
Bibcode: 1974ApJ...187L..85M
Altcode:
The white-light coronagraph experiment has made frequent, periodic
observations of the solar corona from 1.5 R0 to 6.0 R0 during the Skylab
mission, and these observations will permit the determination of the
three-dimensional extent of coronal forms. There are several time
scales on which visual changes in coronal structures occur, ranging
from approximately one-half rotation to less than hours. A number of
events corresponding to the shortest time scale - coronal transients
- cause major restructuring of the corona. Subject headings: corona,
solar - solar wind
Title: The High Altitude Observatory white light coronagraph.
Authors: MacQueen, R. M.; Gosling, J. T.; Hildner, E.; Munro, R. H.;
Poland, A. I.; Ross, C. L.
Bibcode: 1974inas.conf..207M
Altcode:
No abstract at ADS
Title: Skylab: a Progress Report (presented by G. Newkirk)
Authors: MacQueen, R. M.
Bibcode: 1974IAUS...57..489M
Altcode:
No abstract at ADS
Title: Airborne far infrared solar spectroscopy.
Authors: Mankin, W. G.; Eddy, J. A.; Lee, R. H.; MacQueen, R. M.
Bibcode: 1974inas.conf..133M
Altcode:
No abstract at ADS
Title: Observations from space of the solar corona/inner zodical light
Authors: Macqueen, R. M.; Ross, C. L.; Matingly, T.
Bibcode: 1973P&SS...21.2173M
Altcode:
Observations, from the Apollo 16 Spacecraft, in lunar orbit, of
the total radiance of the K + F corona, from 3 R⊙ to
55 R⊙ are presented and discussed. The logarithmic
slope of the K + F coronal radiance, in the region r > 20
R⊙, is found to be n = 1.93, slightly less steep than
previous determinations. The photometric axis of the radiance is found
to be displaced 3 ± 1° north of the ecliptic, for the region r >
20 R⊙, and this displacement is interpreted as an annual
variation due to non-coincidence of the ecliptic and the symmetry axis
of the zodiacal cloud.
Title: Study of He I Emission Lines in the Solar Atmosphere. II. The
Infrared Lines at 10 830 A and 20 581 A
Authors: Streete, J. L.; MacQueen, R. M.; Tandberg-Hanssen, E.
Bibcode: 1973A&A....28..125S
Altcode:
Summary. The 20581 A line of the He I singlet series has been
observed for the first time in two quiescent prominences with a new
all-reflective system. Simultaneously we observed the corresponding
triplet line at 10830 A and studied the triplet-singlet line intensity
ratio. librium, we find the ratio to vary from about 125 to 575 in
different parts of the prominences observed. We deduce from these
data that the ratio is determined by the optical depth in the 584 A
resonance line, whose net radiative bracket exhibits values between
approximately 5 x i0- and 2 x i0- . While this ratio should have values
around 45 for a prominence plasma in local thermodynamic equi Key words:
helium lines - prominences - excitation conditions
Title: The Outer Solar Corona as Observed from Skylab: Preliminary
Results.
Authors: Poland, A. I.; Gosling, J. T.; Hildner, E. G.; MacQueen,
R. M.; Munro, R. H.; Ross, C. L.
Bibcode: 1973BAAS....5..419P
Altcode:
No abstract at ADS
Title: Observed Streamer Curvature in the Outer Solar Corona.
Authors: Wilson, D. C.; MacQueen, R. M.
Bibcode: 1973BAAS....5..446W
Altcode:
No abstract at ADS
Title: Observations of Far Infrared Atmospheric Windows at 44
cm-1 and 50 cm-1 from Pikes Peak
Authors: Mankin, W. G.; Eddy, J. A.; MacQueen, R. M.; Lee, R. H.;
Querfeld, C. W.
Bibcode: 1973NPhS..245....8M
Altcode: 1973Natur.245....8M
ABSORPTION by atmospheric water vapour seriously restricts astronomical
observations from the ground in the far infrared region of the
spectrum. Between 300 cm-1 and 18 cm-1, the
atmosphere is nearly opaque from the ground, except from high mountain
sites where weak windows appear at 29 and 22 cm-1 (350 and
450 µm). These windows were first observed by Gebbie1;
they have since been used by several investigators for mountain top
astronomical measurements2-10. To our knowledge, there
have been no astronomical observations from the ground in the region
between 300 cm-1 and the 29 cm-1 window. In this
frequency decade of the electromagnetic spectrum astronomy has required
the use of aircraft11-16 and balloons17-24
as observing platforms.
Title: Measurements of the Solar Brightness Temperature in the
Far Infrared
Authors: Eddy, J. A.; Lee, R. H.; MacQueen, R. M.; Mankin, W. G.
Bibcode: 1973BAAS....5..271E
Altcode:
No abstract at ADS
Title: Solar Corona Photography
Authors: MacQueen, R. M.; Ross, C. L.; Evans, R. E.
Bibcode: 1973NASSP.330R..34M
Altcode:
No abstract at ADS
Title: Observations of Coronal Forms: 31 July - 13 September 1971
Authors: MacQueen, R. M.; Ross, C. L.; Hansen, R. T.; Dollfus, A.;
Mouradian, Z.; Worden, A.
Bibcode: 1972BAAS....4Q.387M
Altcode:
No abstract at ADS
Title: Observations of Coronal Forms: 7 March - 7 June 1970
Authors: Hansen, R. T.; Hansen, S. F.; Newkirk, G. A.; MacQueen,
R. M.; Gosling, J. T.; Poland, A. I.
Bibcode: 1972BAAS....4T.383H
Altcode:
No abstract at ADS
Title: The intermediate infrared coronal radiance.
Authors: Mankin, W. G.; MacQueen, R. M.; Lee, R. H.
Bibcode: 1971BAAS....3R.262M
Altcode:
No abstract at ADS
Title: Computer Controlled Telescope and Interferometer for Eclipse
Observations
Authors: Mankin, William G.; MacQueen, Robert M.; Lee, Robert H.
Bibcode: 1971fosp.conf..267M
Altcode:
No abstract at ADS
Title: Far infrared airborne spectroscopy.
Authors: Eddy, J. A.; Lee, R. H.; Léna, P. J.; MacQueen, R. M.
Bibcode: 1970ApOpt...9..439E
Altcode:
Equipment and techniques employed in an airborne far ir (80-400 μ)
spectral measurement of the solar brightness temperature are described,
with particular attention paid to the scanning Michelson interferometer
and the radiometric calibration. The airborne performance of several
telescopic guiding systems, a liquid helium cooled bolometer, and golay
cells are discussed, summarizing experience gained on twenty-five jet
aircraft flights.
Title: A computer-controlled infrared eclipse telescope.
Authors: Lee, R. H.; MacQueen, R. M.; Mankin, W. G.
Bibcode: 1970ApOpt...9.2653L
Altcode:
No abstract at ADS
Title: Far Infrared Measurement of the Solar Minimum Temperature
Authors: Eddy, John A.; Léna, Pierre J.; MacQueen, Robert M.
Bibcode: 1969SoPh...10..330E
Altcode:
Radiometric measurement of the brightness temperature of the mean
solar disk has been made in the wavelength range from 238 μ to 312
μ (42.1 cm-1 to 32.1 cm-1), using a Michelson
interferometer of resolution 0.25 cm-1, carried on the NASA
research aircraft at altitude 12.6 km. A mean temperature 4370 ± 260
K is obtained. The result is compared with other measurements of the
solar minimum temperature and with the prediction of the BCA Model.
Title: The Temperature Minimum from Far-Infrared Measurements
Authors: Eddy, John A.; Lena, Pierre J.; MacQueen, R. M.
Bibcode: 1969BAAS....1..275E
Altcode:
No abstract at ADS
Title: Solar Brightness Temperature and Spectra: 80-400 Microns
Wavelength
Authors: Eddy, John A.; Léna, Pierre J.; MacQueen, R. M.
Bibcode: 1969BAAS....1Q.187E
Altcode:
No abstract at ADS
Title: Infrared scattering observations in the upper atmosphere
Authors: Eddy, John A.; MacQueen, Robert M.
Bibcode: 1969JGR....74.3322E
Altcode:
Observations of sky emission and absorption in the far infrared (mean
wavelength 120 μ) and, simultaneously, sky emission at wavelength 6 μ
have been made by P. Kuhn (ESSA) from the NASA CV-990 aircraft flying
at 12-km altitude over the middle Pacific at latitudes 10°-15°N. A
lack of correlation between the near- and far-infrared data, especially
during times of visible cirrus cloud cover above the aircraft, indicates
a wavelength-dependent atmospheric phenomenon, which is interpreted as
scattering. The contributions of scattering by molecules, aerosols,
water drops, and ice crystals in the upper atmosphere are estimated,
and it is shown that the latter water drops and ice crystals may account
for the observed phenomenon. The possible influence of scattering on
past high-altitude solar observations is briefly discussed.
Title: Infrared Observations of the Outer Solar Corona
Authors: MacQueen, R. M.
Bibcode: 1968ApJ...154.1059M
Altcode:
Observations of the outer solar corona at wavelength 2.2 ,~ have been
carried out in two experiments: during the period of totality of the
solar eclipse of November 12, 1966, with the use of a ground-based
telescope, and during a stratospheric balloon ifight on January 9,
1967, by employing a coronagraph. The experiments are discussed, and
the coronal radiance is presented over the range 3-10 Ro. The presence
of four features is attributed to thermal emission of interplanetary
dust. Scans obtained from the balloon experiment over a range of
position angles show isophotes peaked away from the ecliptic at a
position which closely coincides with the invariable plane. Attempts
to assess the origin of the continuum radiance are presented and lead
to calculations of a scattered infrared F- coronal component and a
thermal component based upon large-particle cross-sections
Title: Infrared Observations of the Outer Solar Corona.
Authors: MacQueen, Robert Moffat
Bibcode: 1968PhDT.........2M
Altcode:
No abstract at ADS
Title: Infrared Observations of Thermal Radiation From Interplanetary
Dust at the Eclipse of November 12, 1966 (ABSTRACT)
Authors: Peterson, Alan W.; MacQueen, Robert M.
Bibcode: 1967NASSP.150...89P
Altcode:
No abstract at ADS
Title: Infrared Observations of the Outer Solar Corona.
Authors: MacQueen, R. M.
Bibcode: 1967AJ.....72Q.814M
Altcode:
The 2.2 p infrared coronal radiance has been measured with a
ground-based telescope during the total solar eclipse of 12 Xovember
1966 from 2Re to 6 Re, and during a stratospheric balloon flight of a
coronagraph, from 3.7 Re to 10 Re. Features superposed on a continuum
corona at 3.5 Re and 4.0 Re were observed in the former circumstances,
and features at 4.0 Ro, 8.7 Re, and 9.25 Re noted from the latter
measurements. Isophotes of the continuum corona obtained from the
balloon flight data show a peak displaced from the ecliptic, and
closely coinciding with the invariable plane of the solar system. The
experiments are discussed, and the observations are presented, and
compared with a model of thermal emission of circumsolar dust.
Title: Near Infrared Radiation from the Solar Atmosphere During the
Total Solar Eclipse of 20 July 1963
Authors: Taylor, J. H.; MacQueen, R. M.
Bibcode: 1964ApOpt...3.1506T
Altcode:
No abstract at ADS