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Title: X-ray orbital modulation of a white dwarf accreting from an L dwarf: The system SDSS J121209.31+013627.7
Authors: Stelzer, B.
De Martino, D.
Casewell, S. L.
Wynn, G. A.
Roy, M.
First Published: 1-Feb-2017
Publisher: EDP Sciences for European Southern Observatory (ESO), Springer Verlag
Citation: Astronomy and Astrophysics, 2017, 598, L6
Abstract: In an XMM-Newton observation of the binary SDSS J121209.31+013627.7, consisting of a white dwarf and an L dwarf, we detect X-ray orbital modulation as proof of accretion from the substellar companion onto the magnetic white dwarf. We constrain the system geometry (inclination as well as magnetic and pole-cap angle) through modelling of the X-ray light curve, and we derive a mass accretion rate of 3.2 × 10-14MȮ/ yr from the X-ray luminosity (~3 × 1029 erg/s). From X-ray studies of L dwarfs, a possible wind driven from a hypothesized corona on the substellar donor is orders of magnitude too weak to explain the observed accretion rate, while the radius of the L dwarf is comparable to its Roche lobe (0.1 RȮ), making Roche-lobe overflow the likely accretion mechanism in this system.
DOI Link: 10.1051/0004-6361/201630038
ISSN: 0004-6361
eISSN: 1432-0746
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2017, EDP Sciences for European Southern Observatory (ESO), Springer Verlag. Deposited with reference to the publisher’s open access archiving policy.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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