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arXiv · 1003.0997

An ultra-massive fast-spinning white dwarf in a peculiar binary system

S. Mereghetti·A. Tiengo·P. Esposito·N. La Palombara·G. L. Israel·L. Stella
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Abstract

White dwarfs typically have masses in a narrow range centered at about 0.6 solar masses (Msun). Only a few ultra-massive white dwarfs (M>1.2 Msun) are known. Those in binary systems are of particular interest because a small amount of accreted mass could drive them above the Chandrasekhar limit, beyond which they become gravitationally unstable. Using data from the XMM-Newton satellite, we show that the X-ray pulsator RX J0648.0-4418 is a white dwarf with mass > 1.2 Msun, based only on dynamical measurements. This ultra-massive white dwarf in a post-common envelope binary with a hot subdwarf can reach the Chandrasekhar limit, and possibly explode as a Type Ia supernova, when its helium-rich companion will transfer mass at an increased rate through Roche lobe overflow.

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S. Mereghetti, A. Tiengo, P. Esposito, N. La Palombara, G. L. Israel, L. Stella. 2010-03-04. An ultra-massive fast-spinning white dwarf in a peculiar binary system. https://doi.org/10.1126/science.1176252

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