Double White Dwarf Merger Products among High-mass White Dwarfs
Abstract
Double white dwarf (double-WD) binaries may merge within a Hubble time and produce high-mass WDs. Compared to other high-mass WDs, the double-WD merger products have higher velocity dispersion because they are older. With the power of Gaia data, we show strong evidence for double-WD merger products among high-mass WDs by analyzing the transverse-velocity distribution of more than 1000 high-mass WDs (0.8-1.3 M⊙). We estimate that the fraction of double-WD merger products in our sample is about 20%. We also obtain a precise double-WD merger rate and its mass dependence. Our merger rate estimates are close to binary population synthesis results and support the idea that double-WD mergers may contribute to a significant fraction of type Ia supernovae.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2020
- DOI:
- 10.3847/1538-4357/ab733c
- arXiv:
- arXiv:1910.09558
- Bibcode:
- 2020ApJ...891..160C
- Keywords:
-
- White dwarf stars;
- Stellar kinematics;
- Stellar ages;
- Type Ia supernovae;
- Bayesian statistics;
- 1799;
- 1608;
- 1581;
- 1728;
- 1900;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 9 pages, 5 figures