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Optical and UV Observations of Spotted Stars

Byrne, P. B.

IUE spectra of Feige 4, a suspected source of extreme-ultraviolet radiation

Boggess, A.; Holm, A. V.

IUE spectra are presented for Feige 4, a DB-type white dwarf. The observed energy distribution is in good agreement with that predicted by a model atmosphere with an effective temperature of 15,500 K and having extremely low hydrogen and metal abundances. These results are evidence against Feige 4 being the source of the apparent extreme-ultraviol…

IUE observations of hot stars

Conti, P. S.

Stellar winds are found in hot and luminous stars of all types. We see evidence of these winds in P Cygni profiles of resonance lines in the UV spectral regions, and obtain density information from them, and from optical emission lines and from free-free radiation in the infrared and radio continua from the ionized plasma. Data recently acquired f…

I.U.E. high resolution observations of hot stars emitting coronal x-rays

Bianchi, Luciana

The far UV resonance lines of a sample of 21 early-type stars, which were observed in the soft X-Ray band with the Einstein satellite, are examined using I.U.E. high resolution spectra to search for possible correlation between the X-Ray coronal emission and far UV spectral properties. In particular, those quantities that can give information on t…

Observational aspects of chromospheres and coronae in hot stars

Stalio, R.

With the advent of high resolution space observations with high sensitivity, stellar atmospheric research has entered a new phase of rapid development. All stars, and especially hot stars, are now recognized to have atmospheric characteristics that were not suspected before. All hot stars that we can observe with sufficient accuracy show chromosph…

Cool luminous stars

Linsky, J. L.

A broad theme emerging from IUE and Einstein observations of cool stars is that magnetic fields control the structure and energy balance of the outer atmospheres of these stars. I summarize the phenomena associated with magnetic fields in the Sun and show that similar phenomena occur in cool luminous stars. High dispersion spectra are providing un…