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arXiv · 1702.07370

sdA in SDSS DR12 are Overwhelmingly Not Extremely Low-Mass (ELM) White Dwarfs

J. J. Hermes·B. T. Gaensicke·Elme Breedt
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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 Msun). 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.

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J. J. Hermes, B. T. Gaensicke, Elme Breedt. 2017-02-23. sdA in SDSS DR12 are Overwhelmingly Not Extremely Low-Mass (ELM) White Dwarfs. https://arxiv.org/abs/1702.07370

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