Pulsation timing of two sdB binaries from TESS

Approximately 30% of sdBs exhibit stable pressure and/or gravity-mode pulsations, which can be used via the timing method to test for companion stars and determine their orbital solutions. We used short cadence data from the Transiting Exoplanet Survey Satellite (TESS) to search for previously undiscovered companions to sdBs.

In this paper, we focus on searching for companions with orbital periods shorter than 13.5days which are detectable within one sector of TESS data (about 27days). The timing method requires that we derive pulsation frequencies in subsets of data significantly shorter than the periods we are searching for, which we set at 0.5-1.5day. We investigated ten sdB stars with previously detected p-mode pulsations for which at least one p-mode pulsation remains detectable with a signal-to-noise ratio >4 within data subsets of duration 0.5-1.5day.