A search for pulsating blue stars in the vicinity of NGC 6791 using Kepler LC data

Abstract

There are 18 known pulsating subdwarf B stars in the field of view of the Kepler spacecraft during phase one. The majority of them were observed in the short cadence mode and have been successfully investigated via asteroseismic methods. Since these stars are important for the stellar evolution theory, we performed a search for blue stars in the vicinity of the open cluster NGC 6791, which was observed by the Kepler in the long cadence mode in the so-called super apertures. We used Q1-Q17 LC data and performed pixel analysis using PyKE and our customized scripts. We preliminary tagged 23 objects and we calculated amplitude spectra to look for periodic signal which exist in the data. We found four stars with significant signal in the amplitude spectra with none of them classified as gravity modes in pulsating hot subdwarfs. Likely, all four objects are binaries, though, spectroscopic observations are needed to sort out our hypothesis.