Lampens, P. ; Mkrtichian, D. ; Lehmann, H. ; Gunsriwiwat, K. ; Vermeylen, L. ; Matthews, J. ; Kuschnig, R.

Poster presented at TASC6/KASC13 Workshop "Asteroseismology in the era of surveys from space and the ground: stars, planets, and the milky way", Leuven, Belgium on 2022-07-11

Abstract: Our modelling of the Algol-type eclipsing binary AS Eri is based on the combination of the MOST and TESS light curves as well as a collection of very precise radial velocities obtained with the spectrographs HERMES and TCES. The primary component is an oEA star of type A3 V. We fitted the light and RV data with the package PHOEBE (Prša et al. 2011) and determined the best fitting model. We used the orbital period of 2.6641496 +/- 0.0000001 days, consistent with the epochs of the MOST and TESS light curves. We obtained the absolute component parameters listed in Table 1 with T eff2 /T eff1 = 0.662 +/- 0.002 (adopting 8500 K for the primary). Although the orbital period appears to be stable on the long term, we show that the models derived for each light curve separately reveal some differences e.g. in the temperature of the companion and the inclination of the system and that the shape of the light curve is affected by a years long modulation. We attribute this to the magnetic activity of the cool component. We intend to study the properties of the pulsations using the new residual light curves in combination with existing and recent high resolution time series spectra collected with the SALT spectrograph.

Keyword(s): Stars: binary: eclipsing ; Stars: binary: spectroscopic ; Stars: binary: evolution ; mass accretion ; Stars: variable ; Stars: oscillations (incl. pulsation)