An Elliptical Binary Orbit Model of GX 1+4
Abstract
The X-ray source GX 1 + 4 (4U 1728-24) was observed by the high-energy X-ray spectrometer on OSO 8 for five days from September 20-24, 1978, and X-rays in the energy range 16-72 keV were analyzed. Measurements of the pulse period, pulsar angular acceleration, and luminosity of GX 1 + 4 are reported. The pulsar light curves obtained in different energy ranges are presented, and it is concluded that the period is about 220 s rather than about 110 s. The observations are combined with those reported by others, and a history of GX 1 + 4 as observed in hard X-rays is presentd. A continuous function for the change in period is inferred that suggests a 304-day periodicity. It is proposed that such a period in the spin-up could be caused by an elliptical orbit of GX 1 + 4 about its red giant companion.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1986
- DOI:
- 10.1086/163832
- Bibcode:
- 1986ApJ...300..551C
- Keywords:
-
- Elliptical Orbits;
- Stellar Orbits;
- X Ray Binaries;
- Companion Stars;
- Eccentric Orbits;
- Light Curve;
- Stellar Models;
- Astrophysics;
- PULSARS;
- X-RAYS: BINARIES