The magnetic SW Sextantis star RX J1643.7+3402 |
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| Authors: | P Rodríguez-Gil I G Martínez-Pais J de la Cruz Rodríguez † |
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| Institution: | Isaac Newton Group of Telescopes, Apdo de Correos 321, E–38700, Santa Cruz de la Palma, Spain;Instituto de Astrofísica de Canarias, C/Via Láctea s/n, E–38200 La Laguna, Tenerife, Spain;Departamento de Astrofísica, Universidad de La Laguna, E–38206 La Laguna, Tenerife, Spain |
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| Abstract: | We present time-resolved spectroscopy and circular spectropolarimetry of the SW Sex star RX J1643.7+3402. We find significant polarization levels exhibiting a variability at a period of 19.38 ± 0.39 min. In addition, emission-line flaring is found predominantly at twice the polarimetric period. These two findings are strong evidences in favour of the presence of a magnetic white dwarf in the system. We interpret the measured periodicities in the context of our magnetic accretion model for SW Sex stars. In contrast with LS Pegasi – the first SW Sex star discovered to have modulated circular polarization – the polarization in RX J1643.7+3402 is suggested to vary at 2(ω?Ω) , while the emission lines flare at (ω?Ω) . However, a 2ω/ω interpretation cannot be ruled out. Together with LS Peg and V795 Her, RX J1643.7+3402 is the third SW Sex star known to exhibit modulated circular polarization. |
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| Keywords: | accretion accretion discs magnetic fields polarization binaries: close stars: individual: RX J1643 7+3402 novae cataclysmic variables |
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