Journal Article

Evidence for an accretion steam in the low-accretion-rate polar J2048

S. Kafka, C. Tappert and R. K. Honeycutt

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 403, issue 2, pages 755-759
Published in print April 2010 | ISSN: 0035-8711
Published online March 2010 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2009.16063.x
Evidence for an accretion steam in the low-accretion-rate polar J2048

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We present new red/near-infrared spectra of the low-accretion-rate polar J204827.9+005008.9. Compared to 2004 spectra in the literature, our 2008 data show more structured emission-line profiles. All emission lines in our spectra have two components at most orbital phases. The stronger component has a sinusoidal velocity variation (K∼ 120 km s−1) and is likely due to irradiation of the inner hemisphere of the secondary star by the white dwarf. Based on the appearance of the Hα Doppler tomogram, the weaker, larger amplitude, line component likely originates in a ballistic stream from the L1 point. J2048 is thought to be accreting via a wind from the secondary star, so the detection of velocity features consistent with the velocities of Roche lobe overflow is unexpected. It appears that J2048 was experiencing an interval of enhanced mass transfer during our observations. We briefly discuss scenarios that might lead to such a situation, such as changes in the chromospheric activity level on the secondary star.

Keywords: stars: individual: J204827.9+005008.9; stars: late-type; stars: magnetic fields; novae, cataclysmic variables

Journal Article.  3526 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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