KIC 4739791: A NEW R CMa-TYPE ECLIPSING BINARY WITH A PULSATING COMPONENT

• Published in: The Astronomical journal 2016-02, Vol.151 (2), p.25
• Main Authors: Lee, Jae Woo, Kim, Seung-Lee, Hong, Kyeongsoo, Koo, Jae-Rim, Lee, Chung-Uk, Youn, Jae-Hyuck
• Format: Article
• Language: English
• Subjects: binaries: eclipsing; Constants; Deltas; Light curve; Mass ratios; Orbitals; Oscillations; Pulsation; Stars; stars: individual (KIC 4739791); stars: oscillations; starspots
• ISSN: 0004-6256; 1538-3881
• DOI: 10.3847/0004-6256/151/2/25

ABSTRACT The Kepler light curve of KIC 4739791 exhibits partial eclipses, the inverse O'Connell effect, and multiperiodic pulsations. Including a starspot on either of the binary components, the light-curve synthesis indicates that KIC 4739791 is in detached or semi-detached configuration with both a short orbital period and a low mass ratio. Multiple frequency analyses were performed in the light residuals after subtracting the binarity effects from the original Kepler data. We detected 14 frequencies: 6 in the low-frequency region (0.1−2.3 days−1) and 8 in the high-frequency region (18.2−22.0 days−1). Among these, six high frequencies with amplitudes of 0.62−1.97 mmag were almost constant over time for 200 days. Their pulsation periods and pulsation constants are in the ranges of 0.048−0.054 days and 0.025−0.031 days, respectively. In contrast, the other frequencies may arise from the alias effects caused by the orbital frequency or combination frequencies. We propose that KIC 4739791 is a short-period R CMa binary with the lowest mass ratio in the known classical Algols and that its primary component is a δ Sct pulsating star. Only four R CMa stars have been identified, three of which exhibit δ Sct-type oscillations. These findings make KIC 4739791 an attractive target for studies of stellar interior structure and evolution.