J/A+A/524/A86ivo://CDS.VizieR/J/A+A/524/A86doi:10.26093/cds/vizier.35240086CDSSouthworth J.Marsh T.R.Gansicke B.T.Steeghs D.Copperwheat C.M.2017-06-29T08:56:21Z2010-11-25T09:18:08ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frcataclysmic-variable-starsccd-photometryspectroscopyWe present VLT spectroscopy and NTT photometry of the faint cataclysmic binary SDSS J003941.06+005427.5. This object shows triple-peaked H{alpha} emission with all three peaks variable in both strength and velocity. We measure an orbital period of 91.395+/-0.093min from the velocity variations of the wings of the Halpha emission line. Using the GALEX and SDSS photometry of this object, we determine a white dwarf temperature of 15000K 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 H{alpha} and HeI 6678{AA} emission features show an accretion disc with a non-uniform brightness and departures from Keplerian flow. The third emission peak is detected only in H{alpha} and at a relatively low velocity amplitude of 202+/-3km/s. 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.2010A&A...524A..86Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/524/A86CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/MNRAS/373/687 : Spectra of 5 cataclysmic variables (Southworth+, 2006)J/A+A/507/929 : Light curves of SDSS J100658.40+233724.4 (Southworth+, 2009)J/A+A/510/A100 : Four new SDSS eclipsing systems (Southworth+, 2010)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/524/A86https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/524/A86http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/524/A86https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/524/A86https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/524/A86http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/524/A86GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/524/A86/obsSpectroscopic observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date of observationdtime.epochdoubleFileNameName of the fits file in sp subdirectorymeta.id;meta.fitscharJ/A+A/524/A86/lcPhotometry of SDSS J003941.06+005427.5recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date (UTC timescale) of the exposure midpointdtime.epochdoublemagApparent magnitude of SDSS J003941.06+005427.5magphot.magfloate_magMeasurement error in the apparent magnitudemagstat.error;phot.magfloat