Optical Studies of UHURU Sources.IV. The Long-Term Behavior of HZ HERCULIS=HERCULES X-1
Abstract
Harvard photographs of HZ Herculis taken during the period reveal the following: (1) The orbital period has remained constant at 1.70017 days to within two parts in l0 since 1900. (2) HZ Her does not always display the 1.7-day light variation. (3) When the 1.7-day variation is not detectable, one observes a second brightness fluctuation with an amplitude of Ampg =0.28 i 0.06 and a period half that of the orbital motion. Subject headings:variable stars - X-ray sources
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1973
- DOI:
- 10.1086/181230
- Bibcode:
- 1973ApJ...182L.109J