[vsnet-alert 9535] First spectroscopy of HS2331+3905

[Boris Gaensicke]

Dear All,

I have the first few spectra of HS2331+3905 in outburst: weak
Hbeta/gamma, which is broad and double-peaked with deep central
absorptions. The last spectrum looks as if they are turning over into
complete absorption lines. No sign of HeII 4686.

For those of you who are unfamiliar with this star: it is a 81min
orbital period CV with a grazing eclipse, very similar to WZ Sge. But it
holds a series of other features,

(1) its white dwarf is pulsating with typical periods of ~5min
(2) its white dwarf is spinning with a period of 1.12min
(3) it probably has permanent superhumps in quiescence
(4) most amazing: the Balmer emission lines show a ~3.5h radial
velocity variation in quiescence, that is in no way related to the
orbital period!

A full account on this fantastic object is given in

http://arxiv.org/abs/astro-ph/0410223

Whatever piece of glass you have at hand - fire away on it.

Clear Skies,

Boris Gaensicke

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Dr. Boris Gaensicke                  www.warwick.ac.uk/go/BorisGaensicke
Assistant Professor                        Boris.Gaensicke at warwick.ac.uk
Department of Physics
University of Warwick
Coventry CV4 7AL                                Tel: +44 (0)2476 574741
UK                                              Fax: +44 (0)2476 692016
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