Discovery of a Nova-Like Cataclysmic Variable in the Kepler Mission Field - Astrophysics > Solar and Stellar AstrophysicsReport as inadecuate

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Abstract: We announce the identification of a new cataclysmic variable star in thefield of the Kepler Mission, KIC J192410.81+445934.9. This system wasidentified during a search for compact pulsators in the Kepler field.High-speed photometry reveals coherent large-amplitude variability with aperiod of 2.94 h. Rapid, large-amplitude quasi-periodic variations are alsodetected on time scales of ~1200 s and ~650 s. Time-resolved spectroscopycovering one half photometric period shows shallow, broad Balmer and He Iabsorption lines with bright emission cores as well as strong He II and Bowenblend emission. Radial velocity variations are also observed in the Balmer andHe I emission lines that are consistent with the photometric period. Wetherefore conclude that KIC J192410.81+445934.9 is a nova-like variable of theUX UMa class in or near the period gap, and it may belong to the rapidlygrowing subclass of SW Sex systems. Based on 2MASS photometry and companionstar models, we place a lower limit on the distance to the system of ~500 pc.Due to limitations of our discovery data, additional observations includingspectroscopy and polarimetry are needed to confirm the nature of this object.Such data will help to further understanding of the behavior of nova-likevariables in the critical period range of 3-4 h, where standard cataclysmicvariable evolutionary theory finds major problems. The presence of this systemin the Kepler mission field-of-view also presents a unique opportunity toobtain a continuous photometric data stream of unparalleled length andprecision on a cataclysmic variable system.

Author: Kurtis A. Williams, Domitilla de Martino, Roberto Silvotti, Ivan Bruni, Patrick Dufour, Thomas S. Riecken, Martin Kronberg, Anjum


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