2M1938+4603 (KIC 9472174) eclipses

Abstract

2M1938+4603 (KIC 9472174) displays a spectacular light curve dominated by a strong reflection effect and rather shallow, grazing eclipses. The orbital period is 0.126d, the second longest period yet found for an eclipsing sdB+dM, but still close to the minimum 0.1-d period among such systems. The phase-folded Kepler light curve was used to detrend the orbital effects from the data set. The amplitude spectrum of the residual light curve reveals a rich collection of pulsation peaks spanning frequencies from ∼50 to 4500uHz. The presence of a complex pulsation spectrum in both the p- and g-mode regions has never before been reported in a compact pulsator.