Massive stars play important roles in many astrophysical systems by providing the radiative and mechanical energy output. They can also produce black holes and neutron stars when they explode. However, the traditional 1D stellar evolution models provide very uncertain predictions for the structure and evolution of massive stars because the radiation acceleration around the envelopes of massive stars at the iron opacity regions can be much larger than the gravitational acceleration. The speaker will show how we can understand the physical processes in massive star envelopes based on a series of first principle global 3D radiation hydrodynamic simulations. These simulations can be used to understand the physical origin of super-Eddington outflows from massive stars and the outburst behavior of luminous blue variables, including the effects of metallicity and rotation. Particularly, the speaker will demonstrate these simulations can directly produce the low frequency variabilities of many O stars as observed by TESS recently. He will also illustrate how these simulation results can be used to improve the traditional 1D stellar evolution calculations, which will provide much more reliable models of massive stars.

BIO
Dr. Yanfei Jiang is currently an associate research scientist in the center for computational astrophysics at Flatiron Institute. He graduated from Tsinghua University in 2008 and got his Ph.D. from Princeton University in 2013. He is interested in radiation magneto-hydrodynamic simulations of various astrophysical systems, including accretion onto compact objects and evolution of massive stars. He is also interested in developing new numerical algorithms to perform these simulations.