Search Publications
EXOSAT Observations of Flare Stars and Coronal Heating
Rodono, M.; Butler, C. J.
A program of observation of dMe stars is described that has been undertaken with EXOSAT as part of a collaboration of groups at Armagh, Catania, and JILA (University of Colorado) for multiband coverage of flare stars. The following conclusions were drawn: (1) The LE X-ray flux varies continuously over time scales of 20 seconds to hours with many s…
EXOSAT- Present Status and Future Prospects
Redfern, R. M.
The design and operation of the ESA Exosat orbiting X-ray observatory (launched in May 1983) are reviewed, and some preliminary results are summarized. The value of X-ray observations for investigating hot sources assumed to be driven by accretion into neutron stars is indicated; the low-energy imaging telescopes, medium -energy experiment, and ga…
Gamma-Ray Astronomy
Wolfendale, A. W.; Houston, B.
A brief description is given of the present status of gamma-ray astronomy, both galactic and extragalactic. More detailed attention is given to a specific question: the nature of the apparent 'gamma-ray sources'. The undoubted correlation of at least some of the sources with dense clouds of gas in the interstellar medium is discussed. A new analys…
Optical and UV Observations of Spotted Stars
Byrne, P. B.
Extreme Helium Stars
Lynas-Gray, A. E.
Results of research into the nature of extreme helium stars are reviewed, covering published and unpublished work carried out over the past 20 years. Three approaches are being used to investigate the nature and evolution of extreme helium stars. Abundance analysis from model atmospheres provides information useful in interpreting the evolution of…
IUE Spectroscopy of Dwarf M Stars
Byrne, P. B.
Observations of Interstellar CO at MM and UV Wavelengths and Diverse Comments on Interstellar Diffuse Lines
McNally, D.
The directions of stars known to exhibit the molecule CN in their interstellar spectra were searched for CO at both millimeter and ultraviolet wavelengths in order to obtain more information about moderately dense interstellar material, which is of value in ascertaining the dynamics of star formation. Results show that where both CO and CN have be…
Ultra-Violet Spectroscopy of Flare Stars
Butler, C. J.; Byrne, P. B.; Andrews, A. D.
Results of an IUE satellite investigation of a selection of nearby dwarf stars of spectral type M are given. Spectra were obtained for seven stars in IUE's long wavelength range and for three stars in the short wavelength range, including both known flare stars and stars as yet not known to flare. The most prominent feature of the long wavelength …
Balloon and IUE Spectra of Early-Type Stars
Bates, B.; Giaretta, D. L.; McCartney, D. J. +1 more
A brief account is given of the balloon flight payloads and an outline is presented of the data reduction from the balloon flights and the IUE observations pertaining to studies of the interstellar gas and to mass loss from super-giant stars. It is noted that the IUE permits extension of the range of observations to the important and weaker MgI an…
Heating of Chromospheres and Coronae in Cool Stars
Mullan, D. J.
Recent evidence is summarized that suggests that neither of two traditional views of chromospheric heating (that the flux of energy required to heat the solar chromosphere) is only a small fraction of the total radiative energy emerging from the solar interior and that chromospheres are heated by acoustic waves generated in the convection zone (wh…