Orbital periods of cataclysmic variables identified by the SDSS: VIII. A slingshot prominence in SDSS J003941.06+005427.5?

J. Southworth, Thomas R. Marsh, B. T. Gänsicke, D. Steeghs, C. M. Copperwheat

Research output: Contribution to journalArticleResearchpeer-review

6 Citations (Scopus)

Abstract

We present VLT spectroscopy and NTT photometry of the faint cataclysmic binary SDSS J003941.06+005427.5. This object shows triple-peaked Ha 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 Ha 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 Ha 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 Ha and at a relatively low velocity amplitude of 202 ± 3 kms-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.

Original languageEnglish
Article numberA86
JournalAstronomy & Astrophysics
Volume524
Issue number4
DOIs
Publication statusPublished - 25 Nov 2010
Externally publishedYes

Keywords

  • binaries: spectroscopic
  • novae, cataclysmic variables
  • stars: dwarf novae

Cite this