A Massive Companion to an Extremely Low-Mass White Dwarf
Abstract
We have recently discovered a remarkable binary system containing a 0.17 Msun tidally distorted white dwarf and an unseen massive companion. LMWD 439 shows peak-to-peak radial velocity variations of 1020 km/s with an orbital period of 88 minutes. The optical photometry rules out main-sequence companions. Based on the mass function alone, there is 62% chance that the companion is more massive than 1.4 Msun. To distinguish between a neutron star and a massive white dwarf companion, we propose a search for X-ray emission from LMWD 439. New milli-second pulsars with companions amenable to spectroscopy are of great interest, as they allow for a measurement of neutron star mass. If the companion is not a neutron star, this system would be a strong candidate for a Type Ia supernova progenitor.
- Publication:
-
XMM-Newton Proposal
- Pub Date:
- October 2011
- Bibcode:
- 2011xmm..prop...48K
- Keywords:
-
- White Dwarf Binaries;
- Neutron Star Binaries;
- Cataclysmic Variables;
- ULXs;
- Black Holes;
- LMWD 439