The high energy X-ray spectrum of 4U 0900-40 observed from OSO 8.
Abstract
The X-ray source 4U 0900-40 (= Vela XR-1) was observed with the high-energy X-ray spectrometer on OSO 8 for one week in 1976 and three weeks in 1978. Spectra of the source are presented above 16 keV. No systematic difference exists between the X-ray eclipse centers and the eclipse centers predicted from optical ephermerides. Short period intrinsic variability in the system's X-ray intensity may be related to changes in the Compton scattering optical depth in the system and does not require sporadic mass transfer via Roche lobe overflow. The 282 s modulation in the source's X-ray flux above 21 keV consists of two essentially similar pulses per period, most easily interpreted as arising from the two different magnetic poles of a rotating neutron star. The secondary appears to be a spherically accreting, magnetic neutron star.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1981
- DOI:
- 10.1086/159382
- Bibcode:
- 1981ApJ...250..355D
- Keywords:
-
- Eclipsing Binary Stars;
- Oso-8;
- Radiant Flux Density;
- X Ray Sources;
- X Ray Spectra;
- Compton Effect;
- Ephemerides;
- Magnetic Poles;
- Magnetic Stars;
- Neutron Stars;
- Periodic Variations;
- Stellar Mass Accretion;
- Variable Stars;
- X Ray Spectroscopy;
- Astrophysics