Observations of the White Dwarf in the U Geminorum System with the Hopkins Ultraviolet Telescope
Abstract
The Hopkins Ultraviolet Telescope was used to obtain an FUV spectrum of U Gem about 10 d after the end of an outburst. Most of the FUV emission from U Gem appears to rise from the white dwarf (WD) in the system. Various possibilities to explain the hot component in the present spectrum are explored. It is most likely due to radiation from the boundary-layer region of the WD surface rather than from the accretion disk which exists in U Gem in quiescence. If the standard picture of boundary-layer emission is correct, then the hot component is not due to ongoing accretion onto the WD because the temperature observed is too low. Delayed emission from a viscously heated, differentially rotating atmosphere is argued to be a more valid explanation.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1993
- DOI:
- 10.1086/172365
- Bibcode:
- 1993ApJ...405..327L
- Keywords:
-
- Cataclysmic Variables;
- Dwarf Novae;
- Far Ultraviolet Radiation;
- Ultraviolet Astronomy;
- Ultraviolet Emission;
- White Dwarf Stars;
- Absorption Spectra;
- Stellar Models;
- Ultraviolet Spectra;
- Astrophysics;
- STARS: INDIVIDUAL CONSTELLATION NAME: U GEMINORUM;
- STARS: NOVAE;
- CATACLYSMIC VARIABLES;
- STARS: WHITE DWARFS;
- ULTRAVIOLET: STARS