Far-Ultraviolet Spectroscopy of the Supersoft X-Ray Binary RX J0513.9-6951
Abstract
We have obtained spectroscopy with the Far Ultraviolet Spectroscopic Explorer of the supersoft X-ray binary RX J0513.9-6951 over a complete binary orbital cycle. The spectra show a hot continuum with extremely broad O VI emission and weak Lyman absorptions. He II emission is weak and narrow, while N III and C III emissions are undetected, although lines from these ions are prominent at optical wavelengths. The broad O VI emission and Lyman absorption show radial velocity curves that are approximately antiphased and have semiamplitudes of ~117+/-40 and 54+/-10 km s-1, respectively. Narrow emissions from He II and O VI show small velocity variations with phasing different from the broad O VI but consistent with the optical line peaks. We also measure considerable changes in the far-ultraviolet continuum and O VI emission-line flux. We discuss the possible causes of the measured variations and a tentative binary interpretation.
Based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer. FUSE is operated for NASA by Johns Hopkins University under NASA contract NAS 5-3298.- Publication:
-
The Astronomical Journal
- Pub Date:
- November 2002
- DOI:
- 10.1086/343839
- arXiv:
- arXiv:astro-ph/0207651
- Bibcode:
- 2002AJ....124.2833H
- Keywords:
-
- Stars: Binaries: Close;
- ISM: Jets and Outflows;
- Stars: Individual: Alphanumeric: RX J0513.9-6951- Ultraviolet Emission;
- X-Rays;
- Astrophysics
- E-Print:
- 21 pages, including 2 tables, 6 figures. To appear in AJ