Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries

Autor: Hermes, J. J., Brown, Warren R., Kilic, Mukremin, Gianninas, A., Chote, Paul, Sullivan, D. J., Winget, D. E., Bell, Keaton J., Falcon, R. E., Winget, K. I., Mason, Paul A., Harrold, Samuel T., Montgomery, M. H.
Rok vydání: 2014
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1088/0004-637X/792/1/39
Popis: 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 less than 4 hr. Our observations identify the first eight tidally distorted white dwarfs, four of which are reported for the first time here, which we use to put empirical constraints on the mass-radius relationship for extremely low-mass (<0.30 Msun) white dwarfs. We also detect Doppler beaming in several of these binaries, which confirms the 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.
Comment: 14 pages, 5 figures, accepted for publication in The Astrophysical Journal
Databáze: arXiv