Variability in the cycle length of the supersoft source RX J0513.9-6951
Abstract
Context: The supersoft X-ray binary RX J0513.9-6951 shows cyclic changes between optical-low / X-ray-on states and optical-high / X-ray-off states. It is supposed to be accreting close to the Eddington-critical limit and driven by “accretion wind evolution”.
Aims: We seek to derive the variations in the characteristic time scales of the long-term optical light curve and to determine the implications for the physical parameters of the system.
Methods: We used existing and new optical monitoring observations covering a total time span of 14 years and compared the durations of the low and high states with the model calculations of Hachisu & Kato.
Results: The cycle lengths and especially the durations of the optical high states show a longterm modulation with variations that, according to the accretion wind evolution model, would imply variations in the mass transfer rate by a factor of 5 on timescales of years.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- April 2008
- DOI:
- 10.1051/0004-6361:20067010
- arXiv:
- arXiv:0802.1998
- Bibcode:
- 2008A&A...481..193B
- Keywords:
-
- stars: individual: RX J0513.9-6951;
- stars: binaries: close;
- stars: white dwarfs;
- accretion;
- accretion disks;
- X-rays: stars;
- galaxies: individual: Large;
- Magellanic Cloud;
- Astrophysics
- E-Print:
- 6 Pages, 5 Figures