The transient periodic X-ray source in Taurus, A0535+26.
Abstract
Eighteen X-ray light curves of the 104-sec periodicity in the Taurus X-ray nova A 0535+26 are analyzed which were obtained by SAS-3 in six energy intervals between 1 and 35 keV during the period from May 30 to June 2, 1975. It is shown that the pulse structure is relatively simple at energies above 19 keV, but develops a complex series of five irregularly spaced maxima at lower energies. The energy spectrum averaged over the 104-sec period is found to be extremely hard, with a best-fit temperature of about 30 keV for the exponential spectrum, an excess at about 15 keV, and a steepening above 20 keV. It is suggested that A 0535+26 may be a compact object in a binary system containing the peculiar Be star HDE 245770. The transient behavior could arise due to episodic mass loss by the primary or because the compact object is in a highly eccentric orbit about the companion, with appreciable mass transfer occurring only at periastron.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1976
- DOI:
- 10.1086/182056
- Bibcode:
- 1976ApJ...204L..67B
- Keywords:
-
- Circular Orbits;
- Light Curve;
- Novae;
- X Ray Sources;
- Binary Stars;
- Companion Stars;
- Energy Spectra;
- Orbit Calculation;
- Pulsed Radiation;
- Astrophysics