sdA in SDSS DR12 are Overwhelmingly Not Extremely Low-Mass (ELM) White Dwarfs
Abstract
In a search for new white dwarfs in DR12 of the Sloan Digital Sky Survey, Kepler et al. 2016 found atmospheric parameters for thousands of objects with effective temperatures below 20,000 K and surface gravities between 5.5 < log g < 6.5. They classified these objects as cool subdwarfs - sdA -
and speculated that many may be extremely low-mass (ELM) white dwarfs (helium-core white dwarfs with masses below 0.3 M☉). We present evidence - using radial velocities, photometric colors, and reduced proper motions - that the vast majority (>99%) of these objects are unlikely to be ELM white dwarfs. Their true identity remains an interesting question.- Publication:
-
20th European White Dwarf Workshop
- Pub Date:
- March 2017
- arXiv:
- arXiv:1702.07370
- Bibcode:
- 2017ASPC..509..453H
- Keywords:
-
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 7 pages, 3 figures, 2 tables. As appears in the ASP Conference Series proceedings of "20th European Workshop Workshop on White Dwarfs" held at the University of Warwick, UK on July 25-29th, 2016