Radial Velocity Confirmation of Two Binary Systems Detected with the Pulsation Timing Method

Abstract

We present follow-up radial velocity (RV) results for the subdwarf B$+$white dwarf binaries TIC 202354658 and TIC 69298924, which were originally identified using the pulsation-timing and Fourier-modulation methods applied to ultra-short-cadence photometric data from the Transiting Exoplanet Survey Satellite ($TESS$). Using spectra obtained with the Gemini-North telescope and the Nordic Optical Telescopes, we derived the radial velocity curves for both targets. The orbital solutions we obtained are consistent with the predictions based on pulsation timing, and they provide more precise orbital information compared with the previously obtained results. We therefore confirm that both TIC 202354658 and TIC 69298924 are binary systems with white dwarf companions. The RV solution of TIC 202354658 indicates a relatively large eccentricity ($e$ = 0.313 $\pm$ 0.013), which would be uncommon for a short orbital period sdB binary.

arXiv commentAccepted for publication in The Astronomical Journal