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A Deeply Eclipsing Detached Double Helium White Dwarf Binary

Parsons, S. G. and Marsh, T. R. and Gänsicke, B. T. and Drake, A. J. and Koester, D. (2011) A Deeply Eclipsing Detached Double Helium White Dwarf Binary. Astrophysical Journal Letters, 735 (2). Art. No. L30. ISSN 2041-8205.

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Using Liverpool Telescope+RISE photometry we identify the 2.78 hr period binary star CSS 41177 as a detached eclipsing double white dwarf binary with a 21,100 K primary star and a 10,500 K secondary star. This makes CSS 41177 only the second known eclipsing double white dwarf binary after NLTT 11748. The 2 minute long primary eclipse is 40% deep and the secondary eclipse 10% deep. From Gemini+GMOS spectroscopy, we measure the radial velocities of both components of the binary from the Hα absorption line cores. These measurements, combined with the light curve information, yield white dwarf masses of M_1 = 0.283 ± 0.064 M_☉ and M_2 = 0.274 ± 0.034 M_☉, making them both helium core white dwarfs. As an eclipsing, double-lined spectroscopic binary, CSS 41177 is ideally suited to measuring precise, model-independent masses and radii. The two white dwarfs will merge in roughly 1.1 Gyr to form a single sdB star.

Item Type:Article
Related URLs:
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Marsh, T. R.0000-0002-2498-7589
Gänsicke, B. T.0000-0002-2761-3005
Additional Information:© 2011 American Astronomical Society. Received 2011 April 15; accepted 2011 May 17; published 2011 June 17. Balmer/Lyman lines in the models were calculated with the modified Stark broadening profiles of Tremblay & Bergeron (2009), kindly made available by the authors. T.R.M and B.T.G acknowledge support from the Science and Technology Facilities Council (STFC) grant number ST/F002599/1. The Liverpool Telescope is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. This work is based on observations obtained at the Gemini Observatory under program ID GN-2011A-DD-1, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciencia e Tecnología (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). Facilities: Liverpool:2m, Gemini:Gillett
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)ST/F002599/1
Subject Keywords:binaries: eclipsing; stars: individual (CSS 41177); white dwarfs
Issue or Number:2
Classification Code:PACS: 97.80.Hn, 97.10.Wn, 95.85.Kr, 97.20.Rp, 97.10.Ri
Record Number:CaltechAUTHORS:20110815-134425598
Persistent URL:
Official Citation:A Deeply Eclipsing Detached Double Helium White Dwarf Binary S. G. Parsons et al. 2011 ApJ 735 L30
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:24863
Deposited By: Jason Perez
Deposited On:15 Aug 2011 23:18
Last Modified:09 Mar 2020 13:19

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