Help, my star is on fire - Carbon burning flames in SAGB stars.
Abstract
We explore the detailed and broad properties of carbon burning in Super Asymptotic Giant Branch (SAGB) stars with a comprehensive grid of MESA models. The location of first carbon ignition, quenching location of the carbon burning flames and flashes, angular frequency of the carbon core, and carbon core mass are studied as a function of the ZAMS mass, initial rotation rate, and mixing parameters such as convective overshoot, semiconvection, thermohaline and angular momentum transport. We find the properties of carbon burning in SAGB models are not a strong function of the initial rotation profile, but are a sensitive function of the strength of overshoot mixing. Increasing the amount of overshoot decreases the initial mass needed for off center and center carbon ignitions. Carbon burning flames show a range of morphologies, which vary as a function of initial mass and convective overshoot strength, with either a series of flashes or a flame which propagates inwards towards the core. We find that only systems with overshoot values ≥0.01 and zero age main sequence (ZAMS) masses ≈7.2-8.0 M⊙ is carbon burning quenched at a significant distance from the center. These results have implications for the formation rate of hybrid C-O-Ne WDs, postulated as supernova Type 1a progenitors.
- Publication:
-
American Astronomical Society Meeting Abstracts #227
- Pub Date:
- January 2016
- Bibcode:
- 2016AAS...22734505F