We study the growth of black holes trapped inside main-sequence stars. Starting from the Bondi accretion framework, we examine the microphysics of the plasma, including nuclear energy generation and energy transport within the accretion flow. We find that the Bondi solution provides an accurate description for black holes with masses between 10^21 and 10^28 g. We also investigate the fate of stars hosting such black holes, including the role of stellar rotation. Importantly, we consider scenarios in which the black holes orbit within the star rather than remaining fixed at its center. We conclude that black holes with masses > 10^21 g will either accrete their host stars on timescales much shorter than the age of the Universe or produce sufficient luminosity to leave observable signatures. The case of lighter black holes remains unclear. We discuss these results in the context of constraints on asteroid-mass primordial black holes from star destruction.
This talk is based on an upcoming paper that completes previous studies on the capture of PBHs by stars and on how asteroid-mass PBHs can be constrained through such processes (2207.07412, 2311.12658, and 2503.03352).