Littlefair, S.P. orcid.org/0000-0001-7221-855X, Dhillon, V.S. orcid.org/0000-0003-4236-9642, Marsh, T.R. et al. (3 more authors) (2007) SDSS J150722.30+523039.8: a cataclysmic variable formed directly from a detached white dwarf/brown dwarf binary? Monthly Notices of the Royal Astronomical Society, 381 (2). pp. 827-834. ISSN 0035-8711
Abstract
We present high-speed, three-colour photometry of the eclipsing cataclysmic variable SDSS J150722.30+523039.8 (hereafter SDSS J1507). This system has an orbital period of 66.61 min, placing it below the observed ‘period minimum’ for cataclysmic variables. We determine the system parameters via a parametrized model of the eclipse fitted to the observed lightcurve by χ2 minimization. We obtain a mass ratio of q= 0.0623 ± 0.0007 and an orbital inclination forumla. The primary mass is Mw= 0.90 ± 0.01 M⊙. The secondary mass and radius are found to be Mr= 0.056 ± 0.001 M⊙ and Rr= 0.096 ± 0.001 R⊙, respectively. We find a distance to the system of 160 ± 10 pc. The secondary star in SDSS J1507 has a mass substantially below the hydrogen burning limit, making it the second confirmed substellar donor in a cataclysmic variable. The very short orbital period of SDSS J1507 is readily explained if the secondary star is nuclearly evolved, or if SDSS J1507 formed directly from a detached white dwarf/brown dwarf binary. Given the lack of any visible contribution from the secondary star, the very low secondary mass and the low He Iλ6678/Hα emission-line ratio, we argue that SDSS J1507 probably formed directly from a detached white dwarf/brown dwarf binary. If confirmed, SDSS J1507 will be the first such system identified. The implications for binary star evolution, the brown dwarf desert and the common envelope phase are discussed.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2007 The Authors. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | binaries: close; binaries: eclipsing; stars: dwarf novae; stars: individual: SDSS J1507+5230; novae; cataclysmic variables |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 03 Apr 2019 11:54 |
Last Modified: | 05 Apr 2019 03:36 |
Status: | Published |
Publisher: | Oxford University Press |
Refereed: | Yes |
Identification Number: | 10.1111/j.1365-2966.2007.12285.x |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:138897 |