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The carbon abundance in the Magellanic Clouds from IUE observations.
Dufour, R. J.; Shields, G. A.; Talbot, R. J., Jr.
Results are given of observations of the UV spectra of several H II regions in the Magellanic Clouds, with emphasis on obtaining the carbon abundance from the UV lines of C II, C III, and C IV. The observations and results are described, and theoretical model calculations are presented of the H II regions and the relative abundances of H, He, C, N…
Large-scale distribution of galactic gamma radiation observed by COS-B
Caraveo, P. A.; Bignami, G. F.; Hermsen, W. +13 more
A complete survey of the Galaxy in high-energy gamma rays was performed aboard the ESA satellite COS-B. Gamma-ray maps were derived for energy ranges between 70 MeV and 5 GeV from 1975-1979, and are presented as both contour maps and as longitude and latitude profiles for three energy intervals. The spectral ratio is derived in the form of a color…
Ultraviolet spectra of planetary nebulae. 6 NGC 7662.
Harrington, J. P.; Lutz, J. H.; Seaton, M. J. +1 more
The planetary nebula NGC 7662 considered in the present investigation has been a popular object for detailed modelling. Two models are considered. In Model I, which is similar to a model considered by Harrington et al. (1979), dust absorption is neglected. The model cannot provide results which are in agreement with two types of observational data…
Outer atmospheres of cool stars. XII. A survey of IUE ultraviolet emission line spectra of cool dwarf stars.
Carpenter, K. G.; Linsky, J. L.; Worden, S. P. +4 more
Quantitative information is obtained on the chromospheres and transition regions of M dwarf stars, in order to determine how the outer atmospheres of dMe stars differ from dM stars and how they compare with the outer atmospheres of quiet and active G and K type dwarfs. IUE spectra of six dMe and four dM stars, together with ground-based photometry…
A study of interstellar absorption at high galactic latitudes. I. Highly ionized gas.
Pettini, M.; West, K. A.
IUE interstellar absorption line data for C IV, Si IV, N V and Fe II, in a sample of 24 distant, early-type stars at high galactic latitudes, are analyzed with other published results in order to study the distribution and physical conditions of highly ionized gas in the halo of the Galaxy. The C IV and Si IV lines, which are detected in front of …
The remarkable spectrum of some material ejected by eta Car.
Davidson, K.; Gull, T. R.; Walborn, N. R.
Some of the outer condensations of the very massive star Eta Carinae have emission-line spectra which convey clues to the nature of the star from which they were ejected. Ground-based spectrograms as well as ultraviolet IUE data on the brightest such condensation is described. Excess nitrogen presumably resulting from the C/N/O cycle implies that …
Atmospheric parameters and carbon abundance of white dwarfs of spectral types C2 and DC.
Koester, D.; Weidemann, V.; Zeidler, E. -M.
Model atmosphere calculations over a wide range of effective temperatures and carbon abundances are used to analyze IUE data obtained between 1200 and 3200 A as well as photometric and spectroscopic data in the visible region for several sets of white dwarfs of spectral types C2 and DC. The carbon abundances relative to helium are found to range f…
High-velocity winds from a dwarf nova during outburst.
Mason, K. O.; Cordova, F. A.
An ultraviolet spectrum of the dwarf nova TW Vir during an optical outburst shows shortward-shifted absorption features with edge velocities as high as 4800 km/s, about the escape velocity of a white dwarf. A comparison of this spectrum with the UV spectra of other cataclysmic variables suggests that mass loss is evident only for systems with rela…
UV radiation from the young Sun and oxygen and ozone levels in the prebiological palaeoatmosphere
Imhoff, C. L.; Canuto, V. M.; Levine, J. S. +1 more
UV measurements of young T-Tauri stars, resembling the Sun at an age of a few million years, have recently been made with the International Ultraviolet Explorer. They indicate that young stars emit up to 104 times more UV than the present Sun. The implications for the origin and evolution of O2 and O3 in the prebio…
H2 fluorescence spectrum from 1200 to 1700 A by electron impact - Laboratory study and application to Jovian aurora
Gladstone, G. R.; Yung, Y. L.; Ajello, J. M. +2 more