The Discovery of Binary White Dwarfs that will Merge within 500 Myr

Details The Discovery of Binary White Dwarfs that will Merge within 500 Myr The Discovery of Binary White Dwarfs that will Merge within 500 Myr

2009-11-09

arxiv.org/abs/0911.1781v2

Astronomy and Astrophysics

Astrophysics

Solar and Stellar Astrophysics

ApJ, accepted version

Scientific paper

We present radial velocity observations of four extremely low-mass (0.2 Msol) white dwarfs. All four stars show peak-to-peak radial velocity variations of 540 - 710 km/s with 1.0 - 5.9 hr periods. The optical photometry rules out main-sequence companions. In addition, no milli-second pulsar companions are detected in radio observations. Thus the invisible companions are most likely white dwarfs. Two of the systems are the shortest period binary white dwarfs yet discovered. Due to the loss of angular momentum through gravitational radiation, three of the systems will merge within 500 Myr. The remaining system will merge within a Hubble time. The mass functions for three of the systems imply companions more massive than 0.46 Msol; thus those are carbon/oxygen core white dwarfs. The unknown inclination angles prohibit a definitive conclusion about the future of these systems. However, the chance of a supernova Ia event is only 1% to 5%. These systems are likely to form single R Coronae Borealis stars, providing evidence for a white dwarf + white dwarf merger mechanism for these unusual objects. One of the systems, SDSS J105353.89+520031.0 has a 70% chance of having a low-mass white dwarf companion. This system will probably form a single helium-enriched subdwarf O star. All four white dwarf systems have unusal mass ratios of < 0.2-0.8 that may also lead to the formation of AM CVn systems.

Affiliated with

Also associated with

No associations

Rating

The Discovery of Binary White Dwarfs that will Merge within 500 Myr 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 The Discovery of Binary White Dwarfs that will Merge within 500 Myr, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Discovery of Binary White Dwarfs that will Merge within 500 Myr will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-50552