Heartbeat Stars and the Ringing of Tidal Pulsations

¹ Jeremiah Horrocks Institute, University of Central Lancashire, Fylde Road, Preston, Lancashire, PR1 2HE England
² Department of Astrophysics and Planetary Science, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 USA
³ California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125 USA
⁴ NASA Ames Research Center, Moffett Field, CA 94035, USA
⁵ SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043, USA

^a e-mail: kmhambleton@uclan.ac.uk

Published online: 23 September 2015

Abstract

With the advent of high precision photometry from satellites such as Kepler and CoRoT, a whole new layer of interesting and astounding astronomical objects has been revealed: heartbeat stars are an example of such objects. Heartbeat stars are eccentric ellipsoidal variables that undergo strong tidal interactions when the stars are almost in contact at the time of closest approach. These interactions deform of the stars and cause a notable light curve variation in the form of a tidal pulse. A subset of these objects (~20%) show prominent tidally induced pulsations: pulsations forced by the binary orbit. We now have a fully functional code that models binary star features (using PHOEBE) and stellar pulsations simultaneously, enabling a complete and accurate heartbeat star model to be determined. In this paper we show the results of our new code, which uses emcee, a variant of mcmc, to generate a full set of stellar parameters. We further highlight the interesting features of KIC 8164262, including its tidally induced pulsations and resonantly locked pulsations.