Absence of Magnetic Suppression in Massive Star Variability

Abstract

Although stochastic low-frequency (SLF) variability is ubiquitous among hot, massive stars, its physical origin remains uncertain. One proposed explanation is that this variability is produced by internal gravity waves (IGWs) excited in the stellar interior by convection in the stellar core or subsurface layers. Strong magnetic fields, however, are expected to significantly attenuate such waves. In this work, we model the conditions for magnetic gravity-wave suppression in 17 magnetic hot stars that exhibit significant SLF variability. We find that in many cases, IGWs excited at frequencies comparable to the observed variability should be strongly suppressed by the magnetic field, sometimes across a substantial fraction of the frequency range containing the observed SLF power. This finding challenges IGWs as a universal explanation for SLF variability in massive stars and motivates the consideration of alternative origins.