Frequency and mode identification of γ Doradus from photometric and spectroscopic observations

Abstract :
The prototype star for the γ Doradus class of pulsating variables was studied employing photometric and spectroscopic observations to determine the frequencies and modes of pulsation. The four frequencies found are self-consistent between the observation types and almost identical to those found in previous studies (1.3641 d^-1, 1.8783 d^-1, 1.4742 d^-1, and 1.3209 d^-1). Three of the frequencies are classified as l, m = (1, 1) pulsations and the other is ambiguous between l, m = (2, 0) and (2, -2) modes. Two frequencies are shown to be stable over 20 yr since their first identification. The agreement in ground-based work makes this star an excellent calibrator between high-precision photometry and spectroscopy with the upcoming TESS observations and a potential standard for continued asteroseismic modelling.

Keywords : line: profiles; techniques: spectroscopic; stars: oscillations; stars: variables: general; Astrophysics - Solar and Stellar Astrophysics
Publication : Monthly Notices of the Royal Astronomical Society, Volume 475, Issue 3, p.3813-3822
DOI : 10.1093/mnras/sty034
bibcode : 2018MNRAS.475.3813B