THE LUMINOUS SUPERSOFT X-RAY SOURCE RXJ0925.7-4758 AS A BINARY ACCRETING WHITE DWARF

Abstract

The luminous super soft X-ray sources (LSSS) are believed to be white dwarf binaries with large mass accretion rates (~1×10^-7 - 6×10^-7M_Θ yr^-1) and the energy source is the steady nuclear burning on the white dwarf (WD) surface. During such high accretion rates, hydrogen shell burning consumes hydrogen at the same rate as the WD accretes. In the present work, the LSSS RXJ0925.7-4758 has been studied to examine whether steady state nuclear burning can contribute to emit super soft X-radiation. The luminosity and effective temperature of the LSSS RXJ0925.7-4758 are calculated using the model proposed by Nomoto et.al., 2007 and the values of luminosity (8.56x10³⁷erg/sec) and effective temperature (94.19 ev) are found to tally well with the observed ones. Using formulas of Hoshi, 1998, the color temperature of the LSSS RXJ0925.7-4758 is calculated which is found to be 106 ev and it is higher than the effective temperature of the source.