On the chromospheric structure of Zeta Aurigae

1993 ◽  
Vol 404 ◽  
pp. 305 ◽  
Author(s):  
Joel A. Eaton
Keyword(s):  
Chromospheric Structure

scholarly journals TRACERS OF CHROMOSPHERIC STRUCTURE. I. Ca II H&K EMISSION DISTRIBUTION OF 13,000 F, G, AND K STARS IN SDSS DR7 SPECTROSCOPIC SAMPLE

2013 ◽  
Vol 145 (5) ◽  
pp. 140 ◽  
Author(s):  
J. K. Zhao ◽  
T. D. Oswalt ◽  
G. Zhao ◽  
Q. H. Lu ◽  
A. L. Luo ◽  
...  
Keyword(s):  
Chromospheric Structure

Chromospheric structure of cool carbon stars

1989 ◽  
Vol 345 ◽  
pp. 543 ◽  
Author(s):  
Donald G. Luttermoser ◽  
Hollis R. Johnson ◽  
Eugene H. Avrett ◽  
Rudolf Loeser
Keyword(s):  
Carbon Stars ◽  
Chromospheric Structure

The chromospheric structure of the cool giant star G Herculis

1994 ◽  
Vol 422 ◽  
pp. 351 ◽  
Author(s):  
Donald G. Luttermoser ◽  
Hollis R. Johnson ◽  
Joel Eaton
Keyword(s):  
Giant Star ◽  
Chromospheric Structure

A Discussion on solar studies with special reference to space observations - OAO observations of magnesium II emission in late-type stars

1971 ◽  
Vol 270 (1202) ◽  
pp. 189-195 ◽  
Keyword(s):  
Special Reference ◽  
Solar Atmosphere ◽  
Preceding Paper ◽  
Astronomical Observatory ◽  
Spectral Features ◽  
Late Type ◽  
The Past ◽  
Cool Stars ◽  
Ultraviolet Observations ◽  
Chromospheric Structure

The presence of Ca II H and K emission and λ = 1083 nm of He I in late-type stars suggests that the outer atmospheres of these stars bear some resemblance to the solar atmosphere. Dr Zirin has discussed the appearance of these features in a number of stars in the preceding paper. Because spectral features in cool stars are most sensitive to temperature differences in the ultraviolet, observations of ultraviolet spectra should yield considerable information concerning the nature of chromospheric structure in stars. Over the past year the Orbiting Astronomical Observatory OAO-2 has scanned a number of bright stars of spectral type G and later in the region 180 to 370 nm with a resolution of about 2.5 nm. I will discuss some of the characteristics of these low-resolution spectra with particular emphasis on the appearance of the λ = 280 nm doublet of Mg II.

Evidence on Chromospheric Structure from Observations of Solar Brightness Distribution at Millimetre Wavelengths

1978 ◽  
Vol 3 (4) ◽  
pp. 256-259 ◽  
Author(s):  
N. R. Labrum
Keyword(s):  
Brightness Distribution ◽  
Aperture Synthesis ◽  
The Other ◽  
Solar Chromosphere ◽  
Quiet Sun ◽  
Preliminary Discussion ◽  
Eclipse Observation ◽  
Solar Brightness ◽  
Chromospheric Structure ◽  
Important Test

Observations of the distribution of millimetre-wavelength brightness over the quiet Sun provide an important test of models of the solar chromosphere. The author and colleagues have recently carried out two investigations of the quiet-Sun brightness at 3 mm wavelength — one by means of a total eclipse observation (Labrum et al. 1978) and the other by aperture synthesis with a two-element interferometer (Archer et al. 1978). I present here a preliminary discussion of these and other measurements of millimetre-wavelength brightness distributions and of their interpretation in terms of chromospheric structure.

scholarly journals Turbulence in the Atmospheres of Eclipsing Binary Stars

1980 ◽  
Vol 51 ◽  
pp. 144-156
Author(s):  
K.O. Wright
Keyword(s):  
Binary Stars ◽  
Large Scale ◽  
Giant Component ◽  
Line Profiles ◽  
Eclipsing Binary ◽  
Multiple Structure ◽  
Eclipsing Binary Stars ◽  
Ultraviolet Observations ◽  
Chromospheric Structure ◽  
Lower Chromosphere

Abstract:A review of the orbits and dimensions of the ζ Aurigae systems is given, based on photometric and spectrographic observations. The Ca II K-line has been studied intensively to determine the extent and uneven structure of the chromospheres of these stars; the multiple structure of this line observed at several eclipses confirms the presence of large-scale clouds in the atmospheres. Measurements of line profiles and equivalent widths show that macroturbulent velocities up to 10 km/sec in the upper chromosphere, and up to 20 km/sec. in the lower chromosphere are present. Microturbulent velocities in the lower chromosphere are about 10 km/sec. Recent ultraviolet observations indicate that the B star in the 32 Cygni system may be within the outer chromosphere of the giant component and its radiation may affect the chromospheric structure more than had previously been suggested.

Association of Coronal Structures with Chromospheric Structure

Nature ◽  
1970 ◽  
Vol 226 (5251) ◽  
pp. 1145-1146 ◽  
Author(s):  
R. G. TESKE ◽  
A. K. HUTCHINSON ◽  
J. R. IWANSKI ◽  
T. SOYUMER
Keyword(s):  
Chromospheric Structure ◽  
Coronal Structures

scholarly journals Diagnostic Use of FE II H & K Wing Emission Lines

1980 ◽  
Vol 51 ◽  
pp. 102-102
Author(s):  
Lawrence E. Cram ◽  
Robert J. Rutten ◽  
Bruce W. Lites
Keyword(s):  
Intensity Variation ◽  
Solar Limb ◽  
Emission Lines ◽  
Small Scale ◽  
Strongly Correlated ◽  
Model Computation ◽  
Diagnostic Use ◽  
Line Structure ◽  
Spatially Resolved ◽  
Chromospheric Structure

The Fe II λ3969.4 line is one of the weak lines in the wings of Ca II H and K that appear in emission near the solar limb, and in the flux spectra of cool giants. In spatially resolved solar spectrograms the line shows very pronounced small-scale spatial intensity variation, which is strongly correlated to the line structure of the local H-wing background, and not at all to the chromospheric structure seen in the H & K cores. A 15-level atomic model computation for iron shows that this behaviour is due to pumping by photons in the wings of the strong Fe II resonance lines near 2600 Å, in the deep photosphere. The λ3969.4 line is therefore deeply controlled, with large sensitivity to photospheric inhomogeneities, while its background is formed much higher. This makes the line a useful diagnostic of stellar photospheric line structure, in contrast to the adjacent H core for which emission indicates chromospheric line structure.

Sign in / Sign up

Export Citation Format

Share Document