Accurate Period Determination of an Eclipsing Binary X-Ray Source in M33
Abstract
We have analyzed the time variability of one of the X-ray sources in M33 observed by both the ROSAT and Einstein Observatory telescopes. The light curve of M33 X-7 exhibits a variability pattern of high and low states, suggesting an eclipsing binary X-ray source. The data suggest a binary period P = 1.78572 days (very close to that of Her X-1) and an eclipse duration of ~0.4 days. The low phase lasts about one-fourth of the period as in Cen X-3.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1993
- DOI:
- 10.1086/187118
- Bibcode:
- 1993ApJ...418L..67S
- Keywords:
-
- GALAXIES: INDIVIDUAL MESSIER NUMBER: M33;
- STARS: BINARIES: ECLIPSING;
- STARS: INDIVIDUAL ALPHANUMERIC: M33 X-7;
- X-RAYS: GALAXIES;
- X-RAYS: STARS