Cygnus X-2
Abstract
N. Marshall and M. G. Watson, X-Ray Astronomy Group, Leicester University, report that analyses of the Ariel 5 ssi observations of Cyg X-2 made between 1974 and 1976 reveal a significant modulation at 9.84 days, consistent with both period and phase of the optical observations reported by Crampton and Cowley (IAUC 3292). The x-ray minimum occurs near phase 0.5 according to their ephemeris, as expected if the modulation is due to obscuration of the x-ray source by matter near the optical star. The full amplitude of the modulation is 30 percent of the mean intensity (2-18 keV).
- Publication:
-
International Astronomical Union Circular
- Pub Date:
- January 1979
- Bibcode:
- 1979IAUC.3318....2M