Pulse profile and refined orbital elements for SMC X-1.
Abstract
Results of a reanalysis of SAS-3 data for SMC X-1, including greatly improved orbital elements, are presented. These elements, when combined with newly available data for the optical companion, Sk 160, yield improved estimates for the masses of SMC X-1 and Sk 160. A significant rate of change of intrinsic pulse period is detected during the course of the four-day observation which is consistent with the average value that was previously deduced from observations separated by 5 years. The X-ray pulse profile, averaged over one orbital cycle and with approximately 15-ms time resolution, is also presented. The pulse profile is found to be constant to within statistics, as a function of orbital phase. The implications of the small observed eccentricities of SMC X-1 and other binary X-ray pulsar systems are discussed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1977
- DOI:
- 10.1086/155603
- Bibcode:
- 1977ApJ...217..543P
- Keywords:
-
- Binary Stars;
- Orbital Elements;
- Pulsars;
- X Ray Astronomy;
- X Ray Stars;
- Companion Stars;
- Eccentricity;
- Pulse Rate;
- Stellar Mass;
- Stellar Mass Accretion;
- Stellar Models;
- Astrophysics