A new eclipsing binary system with a pulsating component detected by CoRoT

TL;DR

This paper reports the discovery of a new eclipsing binary system with a pulsating component observed by CoRoT, revealing detailed orbital and pulsation characteristics and suggesting a gamma Doradus classification.

Contribution

It presents the first detailed analysis of CoRoT 102980178, identifying its binary and pulsation properties and proposing its classification as a gamma Doradus type pulsator.

Findings

Discovered a semi-detached eclipsing binary with pulsations.

Identified primary star as the pulsating component.

Detected pulsation frequencies at 2.75 c/d and 0.21 c/d.

Abstract

We report the discovery of CoRoT 102980178 (R.A.= 06:50:12.10, Dec.= -02:41:21.8, J2000) an Algol-type eclipsing binary system with a pulsating component (oEA). It was identified using a publicly available 55 day long monochromatic lightcurve from the CoRoT initial run dataset (exoplanet field). Eleven consecutive 1.26m deep total primary and the equal number of 0.25m deep secondary eclipses (at phase 0.50) were observed. The following light elements for the primary eclipse were derived: HJD_MinI= 2454139.0680 + 5.0548d x E. The lightcurve modeling leads to a semidetached configuration with the photometric mass ratio q=0.2 and orbital inclination i=85 deg. The out-of-eclipse lightcurve shows ellipsoidal variability and positive O'Connell effect as well as clear 0.01m pulsations with the dominating frequency of 2.75 c/d. The pulsations disappear during the primary eclipses, which indicates the primary (more massive) component to be the pulsating star. Careful frequency analysis reveals the second independent pulsation frequency of 0.21 c/d and numerous combinations of these frequencies with the binary orbital frequency and its harmonics. On the basis of the CoRoT lightcurve and ground based multicolor photometry, we favor classification of the pulsating component as a gamma Doradus type variable, however, classification as an SPB star cannot be excluded.