Radius Constraints From High-Speed Photometry Of 20 Low-Mass White Dwarf Binaries

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Date

2014-09

Authors

Hermes, J. J.
Brown, Warren R.
Kilic, Mukremin
Gianninas, A.
Chote, Paul
Sullivan, Denis J.
Winget, D. E.
Bell, Keaton J.
Falcon, Ross E.
Winget, K. I.

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Volume Title

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Abstract

We carry out high-speed photometry on 20 of the shortest-period, detached white dwarf binaries known and discover systems with eclipses, ellipsoidal variations (due to tidal deformations of the visible white dwarf), and Doppler beaming. All of the binaries contain low-mass white dwarfs with orbital periods of less than four hr. Our observations identify the first eight tidally distorted white dwarfs, four of which are reported for the first time here. We use these observations to place empirical constraints on the mass-radius relationship for extremely low-mass (<= 0.30 M-circle dot) white dwarfs. We also detect Doppler beaming in several of these binaries, which confirms their high-amplitude radial-velocity variability. All of these systems are strong sources of gravitational radiation, and long-term monitoring of those that display ellipsoidal variations can be used to detect spin-up of the tidal bulge due to orbital decay.

Department

Astronomy

Description

Keywords

binaries: close, galaxy: stellar content, stars: variables: general, white dwarfs, initial mass, nltt 11748, kepler observations, eclipsing binary, merger, systems, metal-rich, helium, evolution, stars, companion, astronomy & astrophysics

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Citation

Hermes, J. J., Warren R. Brown, Mukremin Kilic, A. Gianninas, Paul Chote, D. J. Sullivan, D. E. Winget et al. "Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries." The Astrophysical Journal, Vol. 792, No. 1 (Sep., 2014): 39.

URI

http://hdl.handle.net/2152/34713

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UT Faculty/Researcher Works