Weighing in on the masses of retired A stars with asteroseismology: K2 observations of the exoplanet-host star HD 212771

Understand

Doppler-based planet surveys point to an increasing occurrence rate of giant planets with stellar mass.

• Such surveys rely on evolved stars for a sample of intermediate-mass stars (so-called retired A stars), which are more amenable to Doppler observations than their main-sequence progenitors.
• However, it has been hypothesised that the masses of subgiant and low-luminosity red-giant stars targeted by these surveys --- typically derived from a combination of spectroscopy and isochrone fitting --- may be systematically overestimated.
• Here, we test this hypothesis for the particular case of the exoplanet-host star HD 212771 using K2 asteroseismology.