ACES New model of the R Cor Bor phenomenon: connecting dusty winds to stellar evolution-Mark Walker
Mark Walker
Manly Astrophysics, Australia
R Cor Bor stars exhibit frequent, deep fading events due to the sudden emergence of thick sprays of dust particles. I will present a new model of the fadings as eclipses by radiation-driven, dusty winds from molecular hydrogen ”snow” clouds on highly eccentric orbits around the star. This model naturally produces deep eclipses with strong asymmetry between ingress and egress. At periastron each cloud is tidally disrupted, creating an unbound debris stream of hydrogen dust and a partially-bound debris stream of helium gas. The helium accretes onto the degenerate core, where it burns via triple-alpha to carbon. Consequently our model of the fading events also accounts for their occurrence specifically in hydrogen-deficient, carbon-rich supergiants.
