posted on 2017-01-09, 15:33authored byR. B. Baxter, P. D. Dobbie, Q. A. Parker, S. L. Casewell, N. Lodieu, M. R. Burleigh, K. A. Lawrie, B. Külebi, D. Koester, B. R. Holland
We present a spectroscopic component analysis of 18 candidate young, wide, non-magnetic, double-degenerate binaries identified from a search of the Sloan Digital Sky Survey Data Release 7 (DR7). All but two pairings are likely to be physical systems. We show SDSS J084952.47+471247.7 + SDSS J084952.87+471249.4 to be a wide DA+DB binary, only the second identified to date. Combining our measurements for the components of 16 new binaries with results for three similar, previously known systems within the DR7, we have constructed a mass distribution for the largest sample to date (38) of white dwarfs in young, wide, non-magnetic, double-degenerate pairings. This is broadly similar in form to that of the isolated field population with a substantial peak around M~0.6 Msun. We identify an excess of ultra-massive white dwarfs and attribute this to the primordial separation distribution of their progenitor systems peaking at relatively larger values and the greater expansion of their binary orbits during the final stages of stellar evolution. We exploit this mass distribution to probe the origins of unusual types of degenerates, confirming a mild preference for the progenitor systems of high-field-magnetic white dwarfs, at least within these binaries, to be associated with early-type stars. Additionally, we consider the 19 systems in the context of the stellar initial mass-final mass relation. None appear to be strongly discordant with current understanding of this relationship.
Funding
This work is based in part on observations made with the Gran
Telescopio Canarias (GTC), operated on the island of La Palma
in the Spanish Observatorio del Roque de los Muchachos of the
Instituto de Astrofisica de Canarias. The INT and the WHT are operated
by the Isaac Newton Group in the Spanish Observatorio del
Roque de los Muchachos of the Instituto de Astrofisica de Canarias.
Based in part on observations made with ESO Telescopes at the La
Silla Paranal Observatory under programme numbers 084.D-1097
and 090.D-0140. Based in part on observations obtained as part
of the VISTA Hemisphere Survey, ESO Progam, 179.A-2010 (PI:
McMahon). This research was made possible through the use of
the AAVSO Photometric All-Sky Survey (APASS), funded by the
Robert Martin Ayers Sciences Fund. This research has made use
of the Simbad database, operated at the Centre de Donn´ees Astronomiques
de Strasbourg (CDS), and of NASA’s Astrophysics
Data System Bibliographic Services (ADS). Funding for the SDSS
and SDSS-II was provided by the Alfred P. Sloan Foundation,
with Participating Institutions, the National Science Foundation,
the U.S. Department of Energy, the National Aeronautics and Space
Administration, the Japanese Monbukagakusho, the Max Planck
Society, and the Higher Education Funding Council for England.
The SDSS Web Site is http://www.sdss.org/. SDSS is managed by
the Astrophysical Research Consortium for the Participating Institutions.
NL acknowledges support from the national program number AYA2010-19136 funded by the Spanish Ministry of Science
and Innovation. NL is a Ram´on y Cajal fellow at the IAC
(number 08-303-01-02). Balmer/Lyman lines in the DA models
were calculated with the modified Stark broadening profiles of
Tremblay & Bergeron (2009), kindly made available by the authors.
History
Citation
Monthly Notices of the Royal Astronomical Society (June 1, 2014) 440 (4): 3184-3201.
Author affiliation
/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy
Version
VoR (Version of Record)
Published in
Monthly Notices of the Royal Astronomical Society (June 1
Publisher
Oxford University Press (OUP), Royal Astronomical Society