München 2019 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 28: Nuclear Astrophysics II
HK 28.3: Talk
Tuesday, March 19, 2019, 17:15–17:30, HS 16
Astrophysical implications of the forbidden transition between 20Ne and 20F — •Dag Fahlin Strömberg1,2 and Gabriel Martínez-Pinedo1,2 — 1Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, Schlossgartenstraße 2, 64289 Darmstadt, Germany — 2Gesellschaft für Schwerionenforschung Darmstadt, Planckstr. 1, D-64259 Darmstadt, Germany
Following carbon burning, intermediate-mass stars (initial mass ∼7–11 solar masses) form degenerate cores composed primarily of 16O and 20Ne. When such cores grow massive and dense enough various electron capture reactions occur due to the high chemical potential of the electron gas. In addition to absorbing electrons these reactions also affect the temperature of the core. Most notably, the double electron capture 20Ne→20F→20O releases enough heat to ignite runaway oxygen burning resulting in either a collapse to a neutron star or a thermonuclear explosion.
In this talk we will discuss the implications of the newly measured forbidden transition (0+→2+) between the ground states of 20Ne and 20F. Its effects are twofold: the ignition occurs at lower central densities and the point of ignition is shifted away from the centre. We will discuss how this happens, the role played by the composition and growth rate of the core, and what this means for the final outcome.
This work is supported by the Deutsche Forschungsgemeinschaft through contract SFB 1245 and the EU COST Action CA16117 (ChETEC).