Two New Tidally Distorted White Dwarfs

dc.contributor.utaustinauthorHermes, J. J.en_US
dc.contributor.utaustinauthorMontgomery, Michael H.en_US
dc.contributor.utaustinauthorWinget, D. E.en_US
dc.creatorHermes, J. J.en_US
dc.creatorKilic, Mukreminen_US
dc.creatorBrown, Warren R.en_US
dc.creatorMontgomery, Michael H.en_US
dc.creatorWinget, D. E.en_US
dc.date.accessioned2016-04-28T19:36:45Z
dc.date.available2016-04-28T19:36:45Z
dc.date.issued2012-04en
dc.description.abstractWe identify two new tidally distorted white dwarfs (WDs), SDSS J174140.49+652638.7 and J211921.96-001825.8 (hereafter J1741 and J2119). Both stars are extremely low mass (ELM, <= 0.2 M-circle dot)WDs in short-period, detached binary systems. High-speed photometric observations obtained at the McDonald Observatory reveal ellipsoidal variations and Doppler beaming in both systems; J1741, with a minimum companion mass of 1.1 M-circle dot, has one of the strongest Doppler beaming signals ever observed in a binary system (0.59% +/- 0.06% amplitude). We use the observed ellipsoidal variations to constrain the radius of each WD. For J1741, the star's radius must exceed 0.074R(circle dot). For J2119, the radius exceeds 0.10R(circle dot). These indirect radius measurements are comparable to the radius measurements for the bloated WD companions to A-stars found by the Kepler spacecraft, and they constitute some of the largest radii inferred for any WD. Surprisingly, J1741 also appears to show a 0.23% +/- 0.06% reflection effect, and we discuss possible sources for this excess heating. Both J1741 and J2119 are strong gravitational wave sources, and the time-of-minimum of the ellipsoidal variations can be used to detect the orbital period decay. This may be possible on a timescale of a decade or less.en_US
dc.description.departmentMcDonald Observatoryen_US
dc.description.sponsorshipNSF AST-0909107en_US
dc.description.sponsorshipNorman Hackerman Advanced Research Program 003658-0252-2009en_US
dc.identifierdoi:10.15781/T20816
dc.identifier.Filename2012_04_twonewtidally.pdfen_US
dc.identifier.citationHermes, J. J., Mukremin Kilic, Warren R. Brown, M. H. Montgomery, and D. E. Winget. "Two new tidally distorted white dwarfs." The Astrophysical Journal, Vol. 749, No. 1 (Apr., 2012): 42.en_US
dc.identifier.doi10.1088/0004-637x/749/1/42en_US
dc.identifier.issn0004-637Xen_US
dc.identifier.urihttp://hdl.handle.net/2152/34904
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.relation.ispartofserialAstrophysical Journalen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.rights.restrictionOpenen_US
dc.subjectbinaries: closeen_US
dc.subjectgalaxy: stellar contenten_US
dc.subjectstars: individual (sdssen_US
dc.subjectj174140.49+652638.7, sdss j211921.96-001825.8)en_US
dc.subjectstars: neutronen_US
dc.subjectstars:en_US
dc.subjectvariables: generalen_US
dc.subjectwhite dwarfsen_US
dc.subjectbinary nltt 11748en_US
dc.subjecteclipsing binaryen_US
dc.subjectsystemen_US
dc.subjectheliumen_US
dc.subjectstarsen_US
dc.subjectdiscoveryen_US
dc.subjectkepleren_US
dc.subjectvariabilityen_US
dc.subjectevolutionen_US
dc.subjectcompanionen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleTwo New Tidally Distorted White Dwarfsen_US
dc.typeArticleen_US

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