The Challenges of Modeling Astrophysical Reacting Flows

Stellar evolution is driven by the changing composition of a star from nuclear reactions. At the late stages of evolution and during explosive events, the timescale can be short and drive strong hydrodynamic flows, making simulations of astrophysical reacting flows challenging. Over the past decades, the standard approach to modeling reactions in simulation codes has been operator splitting, using implicit integrators for reactions. Here we review the state-of-the-art, explore some of the assumptions in this standard approach, and describe some techniques for improving the efficiency and accuracy of astrophysical reacting flows.