Optical/UV counterpart of the supersoft transient X-ray source RX J0513.9-6951 in the Large Magellanic Cloud.
Abstract
Optical and IUE observations of the ROSAT X-ray transient RX J0513.9-6951 show this object to be remarkably similar to Cal 83, the prototype of luminous supersoft sources which is also located in the LMC. The counterpart is a B ~ 17 mag blue star which apparently did not vary much around the time of the X-ray outburst. Spectrophotometry reveals narrow and broad emission lines of H, He II, NV, and O VI, whereas the λλ1548, 50 C IV resonance doublet is very weak. Radial velocity variations by ~100 km/s suggest binary nature and a systemic velocity close to the bulk motion of the LMC. We discuss the hypothesis that the source is mainly powered by nuclear burning on the surface of a white dwarf rather than by accretion, and we argue that the X-ray outburst was triggered by a reduced accretion rate.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 1993
- Bibcode:
- 1993A&A...278L..39P
- Keywords:
-
- Accretion Disks;
- B Stars;
- Blue Stars;
- Magellanic Clouds;
- Neutron Stars;
- Ultraviolet Photometry;
- Visible Spectrum;
- White Dwarf Stars;
- X Ray Sources;
- X Ray Spectra;
- Compton Effect;
- Iue;
- Line Spectra;
- Radial Velocity;
- Rosat Mission;
- Sky Surveys (Astronomy);
- Stellar Spectrophotometry;
- X Ray Telescopes;
- Astrophysics