Two stars, of and , exhaust core hydrogen and develop helium cores surrounded by…
PHYSICS · Multi-part · Fermi University Physics · Astrophysics & Cosmology · Stellar structure, energy generation and evolution · Stellar structure, energy generation and evolution
Stars from the Inside, Ch Stellar evolution: from the Hayashi track to the iron core, and the ages of clusters
Problem
Two stars, of 1.0M⊙ and 5.0M⊙, exhaust core hydrogen and develop helium cores surrounded by hydrogen-burning shells.
((a)) For each star, predict whether its crossing of the Hertzsprung gap is rapid (on the core's Kelvin-Helmholtz timescale) or slow (on the shell-burning timescale), stating whether its core does or does not exceed the Schonberg-Chandrasekhar fraction qSC≈0.08.
((b)) For each star, predict whether core helium ignition occurs as a flash or quiescently, justifying the answer from the expected degree of electron degeneracy in each core.