The ELM Survey. IX. A Complete Sample of Low Mass White Dwarf Binaries in the SDSS Footprint

Abstract

We present the discovery of 17 double white dwarf (WD) binaries from our on-going search for extremely low mass (ELM) <0.3 Msun WDs, objects that form from binary evolution. Gaia parallax provides a new means of target selection that we use to evaluate our original ELM Survey selection criteria. Cross-matching the Gaia and Sloan Digital Sky Survey (SDSS) catalogs, we identify an additional 36 ELM WD candidates with 17<g<19 mag and within the 3-sigma uncertainties of our original color selection. The resulting discoveries imply the ELM Survey sample was 90% complete in the color range -0.4 < (g-r)_0 < -0.1 mag (approximately 9,000 K < Teff < 22,000 K). Our observations complete the sample in the SDSS footprint. Two newly discovered binaries, J123950.370-204142.28 and J232208.733+210352.81, have orbital periods of 22.5 min and 32 min, respectively, and are future LISA gravitational wave sources.

14 pages, 10 figures, published ApJ

References in corpus (14)

• Laser Interferometer Space Antenna
• A catalogue of white dwarfs in Gaia EDR3
• New white dwarf stars in the Sloan Digital Sky Survey Data Release 10
• The ELM Survey. VIII. 98 Double White Dwarf Binaries
• Precise Atmospheric Parameters for the Shortest Period Binary White Dwarfs: Gravitational Waves, Metals, and Pulsations
• Gaia Data Release 2 Catalogue of Extremely-low Mass White Dwarf Candidates
• A New Gravitational Wave Verification Source
• Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries
• The ELM Survey South. I. An Effective Search for Extremely Low Mass White Dwarfs
• A population synthesis fitting of the $Gaia$ resolved white dwarf binary population within 100 pc
• The sdA problem I: Physical Properties
• A Gemini Snapshot Survey for Double Degenerates
• The Discovery of Two LISA Sources within 0.5 kpc
• Doppler beaming factors for white dwarfs, main sequence stars, and giant stars Limb-darkening coefficients for 3D (DA and DB) white dwarf models

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• An Eclipsing 47 minute Double White Dwarf Binary at 400 pc
• Discovery of four new EL CVn-type binaries in the Gaia eclipsing binaries
• Exploring the internal rotation of the extremely low-mass He-core white dwarf GD 278 with TESS asteroseismology