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RX J1313.2-3259, a long-period Polar discovered with ROSAT

H. -C. Thomas·K. Beuermann·V. Burwitz·K. Reinsch·A. D. Schwope
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Abstract

We report observations of a new AM Herculis binary identified as the optical counterpart of the X-ray source RX J1313.2-3259, detected during the ROSAT All-Sky Survey (RASS). It has an orbital period of 251 min and is strongly modulated at optical wavelengths. The long-term behavior is characterized by a pronounced variation in X-rays between the RASS and two subsequent pointings (decrease by a factor 40 in count rate) and by moderate changes in the optical brightness (up to a factor 5). The X-ray spectrum is dominated by a soft quasi-blackbody component, with a smaller contribution from thermal bremsstrahlung. Measurements of high circular polarization confirm its classification as a Polar with a magnetic field strength of 56 MG. The average visual magnitude of RX J1313.2-3259 is V = 16 mag, for its distance we get 200 pc.

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H. -C. Thomas, K. Beuermann, V. Burwitz, K. Reinsch, A. D. Schwope. 1999-11-11. RX J1313.2-3259, a long-period Polar discovered with ROSAT. https://arxiv.org/abs/astro-ph/9911200

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