A Transparent Window into Early-type Stellar Variability

Subsurface convection zones are ubiquitous in early-type stars. Driven by narrow opacity peaks, these thin convective regions transport little heat but play an important role setting the magnetic properties and surface variability of Here we demonstrate that \emph{not} present as wide a range stars previously believed. In particular, there which 1D stellar evolution models report to be convectively unstable fall below critical Rayleigh number for onset convection. For sub-solar metallicity this opens up \emph{stability window} no subsurface zones. LMC stability region extends roughly between $8M_\odot$ $16M_\odot$, increasing -- $35M_\odot$ SMC metallicity. Such windows then excellent target probing relative influence other sources photometric massive