Astronomy and Astrophysics – Astrophysics
Scientific paper
2002-08-07
Astrophys.J. 577 (2002) L27-L30
Astronomy and Astrophysics
Astrophysics
to appear in Astrophysical Journal Letters
Scientific paper
10.1086/344085
The discovery of two accreting millisecond X-ray pulsars in binaries with 43 minute orbital periods allows for a new probe of the donor's structure. For XTE J1751-305, only a hot white dwarf (WD) can fill the Roche Lobe. A cold He WD is a possible solution for XTE J0929-314, though I will show that evolutionary arguments make a hot WD more likely. In addition to being larger than the T=0 models, these finite entropy, low-mass (<0.03 solar masses) WDs have a minimum mass for a fixed core temperature. If they remain hot as they lose mass and expand, they can ``evaporate'' to leave an isolated millisecond radio pulsar. They also adiabatically expand upon mass loss at a rate faster than the growth of the Roche radius if the angular momentum deposited in the disk is not returned to the donor. If the timescale of the resulting runaway mass transfer is shorter than the viscous timescale in the outer disk, then the mass transfer instability of Ruderman and Shaham for He WDs would be realized. However, my estimates of these timescales still makes the instability unlikely for adiabatic responses. I close by noting the possible impact of finite T WDs on our understanding of AM CVn binaries.
No associations
LandOfFree
Hot White Dwarf Donors in Ultracompact X-Ray Binaries does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Hot White Dwarf Donors in Ultracompact X-Ray Binaries, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hot White Dwarf Donors in Ultracompact X-Ray Binaries will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-538741