The orbital period of 4U/MXB 1636-53 (V801 Arae).
Abstract
The results of CCD photometry of the optical counterpart (V801 Arae) of the X-ray burst source 4U/MXB 1636-53, obtained between 1984 and 1988 are reported. From these data, and additional measurements discussed previously, a linear orbital ephemeris P(orb) = 3.803878 + or - 0.000022 h covering the interval between 1980 and 1988 is derived. The results confirm that substantial night-to-night variations occur in the shape of the light curve, superposed on the periodic brightness variations. No evidence is found for a relation between orbital phase and the delays of optical bursts relative to the coincident X-ray bursts. The variation with orbital phase of the corresponding ratios of optical to X-ray burst fluences and peak fluxes does not follow the average optical light curve. These results suggest that substantial long-term changes occur in the spatial distribution of reprocessing matter in the binary system.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 1990
- Bibcode:
- 1990A&A...234..181V
- Keywords:
-
- Astronomical Photometry;
- Orbital Mechanics;
- Stellar Orbits;
- X Ray Binaries;
- Ephemerides;
- Light Curve;
- Periodic Variations;
- Astrophysics