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Astron. Astrophys. 328, 571-578 (1997)

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RX J0719.2+6557: a new eclipsing polar

G.H. Tovmassian 1, J. Greiner 2, F.-J. Zickgraf 2, P. Kroll 3, J. Krautter 4, I. Thiering 4, S.V. Zharykov 5 and A. Serrano 6

1 Observatorio Astronomico Nacional, Instituto de Astronomía, UNAM, AP 877, 22860, Ensenada, B.C., México
2 Max-Planck-Institut für extraterrestrische Physik, D-85740 Garching, Germany
3 Sternwarte Sonneberg, D-96515 Sonneberg, Germany
4 Landessternwarte Königstuhl, D-69117 Heidelberg, Germany
5 Special Astronomical Observatory, 357147 Nizhnij Arkhyz, Russia
6 Instituto Nacional de Astrofísica Optica y Electrónica, AP 51 y 216, Puebla, Pue., Mexico

Received 31 December 1996 / Accepted 1 August 1997

Abstract

A new magnetic cataclysmic variable is identified as the counterpart of the X-ray source RX J0719.2+6557 which has been discovered during the ROSAT all-sky survey. Optical spectroscopy of the [FORMULA] object revealed a pattern of Balmer and strong He II emission lines which are characteristic for cataclysmic variables. The emission lines show radial velocity variations with a period of 98.2 min with no significant phase shifts among them. This coincides with the period of deep eclipses (up to 4 mag) in the photometric light curve of the system. The phase of the eclipse relative to the spectroscopic phase, and its structure indicates that the dominant source of emission is located on the stream of accreting matter, which is eclipsed by the secondary companion. The emission lines bear evidence of a weaker component, most probably the contribution from the heated side of the secondary star. These features define this object as a probable polar in a high state in which the secondary is irradiated by the X-rays originating from magnetically driven accretion onto the white dwarf.

Key words: stars: cataclysmic variables – accretion – stars: individual: RX J0719.2+6557 – binaries: eclipsing – X-rays: stars

Present address: Astrophysical Institute Potsdam, An der Sternwarte 16, D-14482 Potsdam, Germany

Present address: Observatoire de Strasbourg, 11 rue de l'Université, F-67000 Strasbourg, France

Send offprint requests to: G.H. Tovmassian (gag@bufadora.astrosen.unam.mx)

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© European Southern Observatory (ESO) 1997

Online publication: March 26, 1998

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