Burleigh, MR;
Marsh, TR;
Gänsicke, BT;
Goad, MR;
Dhillon, VS;
Littlefair, SP;
Wells, M;
... Lewis, F; + view all
(2006)
The nature of the close magnetic white dwarf + probable brown dwarf binary SDSS J121209.31+013627.7*.
Monthly Notices of the Royal Astronomical Society
, 373
(4)
pp. 1416-1422.
10.1111/j.1365-2966.2006.11030.x.
Preview |
Text
Farihi_MNRAS-2006-Burleigh-1416-22.pdf Download (652kB) | Preview |
Abstract
Optical time series photometry of the short-period magnetic white dwarf + probable brown dwarf binary SDSS J121209.31+013627.7 reveals pulse-like variability in all bands from i′ to u′, increasing towards bluer wavelengths and peaking at u′. These modulations are most likely due to a self-eclipsing accretion hot spot on the white dwarf, rotating into view every 88.43 min. This period is commensurate with the Ha radial velocity period of ≈90 min, and consistent with the rotation period of the accretor being equal to the binary orbital period. We combine our observations with other recently reported results to provide an accurate ephemeris. We also detect the system in X-rays with Swift, and estimate the accretion rate at ≈ 10 -13 M ⊙ yr -1. We suggest that SDSS J121209.31+013627.7 is most likely a magnetic cataclysmic variable in an extended state of very low accretion, similar to the well-studied polar EF Eri. Alternatively, the putative brown dwarf is not filling its Roche lobe and the system is a detached binary in which the white dwarf is efficiently accreting from the wind of the secondary. However, it is unclear whether an L dwarf wind is strong enough to provide the measured accretion rate. We suggest further observations to distinguish between the Roche lobe overflow and wind accretion scenarios.
| Type: | Article |
|---|---|
| Title: | The nature of the close magnetic white dwarf + probable brown dwarf binary SDSS J121209.31+013627.7* |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1111/j.1365-2966.2006.11030.x |
| Publisher version: | http://dx.doi.org/10.1111/j.1365-2966.2006.11030.x |
| Language: | English |
| Additional information: | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2006 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
| Keywords: | stars: low-mass, brown dwarfs; novae, cataclysmic variables; white dwarfs |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1477407 |
Loading...
Loading...Loading...Loading...Archive Staff Only
 |
View Item |
