The discovery of a massive white dwarf in the peculiar binary system HD 49798/RX J0648.0-4418
arXiv:0911.3809 · doi:10.1063/1.3475362
Abstract
An XMM-Mewton observation performed in May 2008 has confirmed that the 13 seconds pulsations in the X-ray binary HD 49798/RX J0648.0-4418 are due to a rapidly rotating white dwarf. From the pulse time delays induced by the 1.55 days orbital motion, and the system's inclination, constrained by the duration of the X-ray eclipse discovered in this observation, we could derive a mass of 1.28+/-0.05 M_sun for the white dwarf. The future evolution of this post common envelope binary system will likely involve a new phase of mass accretion through Roche-lobe overflow that could drive the already massive white dwarf above the Chandrasekhar limit and produce a Type Ia supernova.
Proceedings of the conference X-Ray Astronomy 2009, Present Status, multiwavelength approach and future perspectives, September 7 - 11, 2009, Bologna, Italy