Magnetic Fields in Low-mass Stars Increase Photometric Masses, Thereby Reducing Inferred Radius Inflation

Abstract

Standard evolution models of a given age provide a relationship between stellar mass and T eff. Based on this, Cruz et al. have derived stellar masses and radii for a sample of Kepler stars using photometry alone: their radii are found to be inflated by up to 100% relative to standard models. However, magnetic fields distort the M–T eff relationship in a systematic way: here, we quantify this distortion, and show that radius inflations in the Cruz et al. stars are likely to be significantly smaller than 100%.