Dust being ejected by stars leads to an interesting multi-physics problem. We simulate the transport of this dust and track the hydrodynamic development of the gas and dust over large domains and time periods.
Details
Stellar luminosity variations and dust hydrodynamics in Asymptotic Giant Branch (AGB) stars, and the consequences for dust survival and mass-loss, remain elusive. We broadly investigate the role of dust and radiation hydrodynamics in the formation of dust and gas structures, heterogeneous clumps, observable in AGB remnants, and planetary nebulae (PNe). Spatial perturbations arise due to luminosity variations from turbulent thermal convection within the star and stellar atmosphere. These variations in the radiation field drive spatial perturbations of the dust and gas field and may be responsible for the formation of larger clumps, such as cometary knots, seen in the PNe phase. We use FLASH for studying this problem at large length and time scales. Simulations are performed in 2D solving the Euler equations with source terms resulting from the particle phase, represented by free Lagrangian points. We implement radiation coupling for the particle phase, modeling radiation heating and acceleration of the particles, and subsequent coupling to the gas phase through non-continuum heat and momentum transfer models.
Research is done in conjunction with Dr. Angela Speck at the University of Texas, San Antonio.