Volume 440, Number 2, September III 2005
|Page(s)||701 - 709|
|Section||Stellar structure and evolution|
|Published online||01 September 2005|
HS 0943+1404, a true intermediate polar
Department of Physics, University of Warwick, Coventry CV4 7AL, UK e-mail: email@example.com
2 Instituto de Astrofísica de Canarias, Vía Láctea, s/n, La Laguna, 38205 Santa Cruz de Tenerife, Spain
3 Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
4 Hida Observatory, Kyoto University, Kamitakara, Gifu 506-1314, Japan
5 Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA
6 Tuorla Observatory, Turku University, Väisäläntie 20, 21500 Piikkiö, Finland
7 Department of Physics, 20014 University of Turku, Finland
8 School of Physics, University of Exeter, Exeter EX4 4QL, UK
9 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
Accepted: 1 June 2005
We have identified a new intermediate polar, HS 0943+1404, as part of our ongoing search for cataclysmic variables in the Hamburg Quasar Survey. The orbital and white dwarf spin periods determined from time-resolved photometry and spectroscopy are min and min, respectively. The combination of a large ratio and a long orbital period is very unusual compared to the other known intermediate polars. The magnetic moment of the white dwarf is estimated to be , which is in the typical range of polars. Our extensive photometry shows that HS 0943+1404 enters into deep (~3 mag) low states, which are also a characteristic feature of polars. We therefore suggest that the system is a true “intermediate” polar that will eventually synchronise, that is, a transitional object between intermediate polars and polars. The optical spectrum of HS 0943+1404 also exhibits a number of unusual emission lines, most noticeably Nλ5680, which is likely to reflect enhanced nitrogen abundances in the envelope of the secondary.
Key words: accretion, accretion disc / stars: binaries: close / stars: novae, cataclysmic variables
© ESO, 2005
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