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Stars with masses of >~ 20 solar masses have short Kelvin times that enable them to reach the main sequence while still accreting from their natal clouds. The resulting nuclear burning produces a huge luminosity and a correspondingly large radiation pressure force on dust grains in the accreting gas. This effect may limit the upper mass of stars that can form by accretion. Indeed, simulations and analytic calculations to date have been unable to resolve the mystery of how stars of 50 solar masses and up form. We present two new ideas to solve the radiation pressure problem. First, we use three-dimensional radiation hydrodynamic adaptive mesh refinement simulations to study the collapse of massive cores. We find that in three dimensions a configuration in which radiation holds up an infalling envelope is Rayleigh-Taylor unstable, leading radiation driven bubbles to collapse and accretion to continue. We also present Monte Carlo radiative transfer calculations showing that the cavities created by protostellar winds provides a valve that allow radiation to escape the accreting envelope, further reducing the ability of radiation pressure to inhibit accretion.
Stellar feedback in the form of radiation pressure and magnetically-driven collimated outflows may limit the maximum mass that a star can achieve and affect the star-formation efficiency of massive pre-stellar cores. Here we present a series of 3D ad
Cosmological simulations of galaxies have typically produced too many stars at early times. We study the global and morphological effects of radiation pressure (RP) in eight pairs of high-resolution cosmological galaxy formation simulations. We find
The enormous radiative and mechanical luminosities of massive stars impact a vast range of scales and processes, from the reionization of the universe, to the evolution of galaxies, to the regulation of the interstellar medium, to the formation of st
We present radiation transfer (RT) simulations of evolutionary sequences of massive protostars forming from massive dense cores in environments of high surface densities. The protostellar evolution is calculated with a detailed multi-zone model, with
Massive low surface brightness galaxies have disk central surface brightnesses at least one magnitude fainter than the night sky, but total magnitudes and masses that show they are among the largest galaxies known. Like all low surface brightness (LS