Issue |
A&A
Volume 524, December 2010
|
|
---|---|---|
Article Number | A86 | |
Number of page(s) | 8 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361/201015633 | |
Published online | 25 November 2010 |
Orbital periods of cataclysmic variables identified by the SDSS
VIII. A slingshot prominence in SDSS J003941.06 + 005427.5?⋆
1
Astrophysics Group, Keele University,
Newcastle-under-Lyme,
ST5 5BG
UK
e-mail: jkt@astro.keele.ac.uk
2
Department of Physics, University of Warwick,
Coventry, CV4 7AL, UK
Received: 24 August 2010
Accepted: 27 September 2010
We present VLT spectroscopy and NTT photometry of the faint cataclysmic binary SDSS J003941.06 + 005427.5. This object shows triple-peaked Hα emission with all three peaks variable in both strength and velocity. We measure an orbital period of 91.395 ± 0.093 min from the velocity variations of the wings of the Hα emission line. Using the GALEX and SDSS photometry of this object, we determine a white dwarf temperature of 15 000 K and a very late (≳L2) spectral type for the companion star. These measurements, plus the relatively long orbital period, suggest that SDSS J003941.06 + 005427.5 may be a post-bounce cataclysmic variable. Doppler maps of the Hα and He I 6678 Å emission features show an accretion disc with a non-uniform brightness and departures from Keplerian flow. The third emission peak is detected only in Hα and at a relatively low velocity amplitude of 202 ± 3 km s-1. We are unable to explain this emission as arising from either the white dwarf, the secondary star, or the accretion disc. We tentatively attribute this mysterious central peak to a coronal loop anchored at the secondary star. If confirmed, this would be the first example of a slingshot prominence in a CV with a low mass-transfer rate and/or a fully convective secondary star.
Key words: stars: dwarf novae / binaries: spectroscopic / novae, cataclysmic variables
Reduced data (photometry and spectroscopy) are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/viz-bin/qcat?J/A+A/524/A86
© ESO, 2010
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.