The RXTE/ASM X-ray light curve of GX301-2

Department of Physics, University of Calgary, Calgary, Canada T2N 1N4

Corresponding author: leahy@iras.ucalgary.ca

Received: 11 April 2002
Accepted: 17 May 2002

Abstract

GX301-2 is an accreting neutron star in an eccentric orbit () with a massive early-type stellar companion. GX301-2 accretes from the stellar wind and exhibits regular X-ray flares approximately 1.4 days prior to periastron passage. Long-term continuous X-ray monitoring of GX301-2 by the RXTE/All-Sky-Monitor has now been carried out for a period of 5 years. These data now comprise the best observations of the orbital X-ray light curve. The main flux peak just prior to periastron is clearly seen, as well as a secondary broad peak near apastron. CGRO/BATSE observations have provided new improved orbital parameters. The constraint on the orbital inclination is examined. Then the GX301-2 orbital light curve is modeled using wind, disk and stream models. The conclusion is that only a stellar wind plus mass stream is consistent with the data. The wind model is further supported by calculations of the stream flow from the primary and the expected orbital phases that the neutron star crosses the stream.