Binarity as the Solution to the Stellar Evolution Enigma Posed by NGC 6791

CARRARO, GIOVANNI; BENVENUTO, OMAR G.

Astrophysical Journal Letters

Institute of Physics Publishing

Año: 2017 vol. 841 p. 10 - 13

2041-8205

Binary evolution is investigated as the source for the extreme horizontal branch (EHB) stars in the old and metal-rich open cluster NGC 6791. Employing an updated version of our binary stellar evolution code, we demonstrate that EHB stars naturally emerge from the common-envelope phase. In sum, the binary model reproduces the observed (T eff, ) and temporal properties of the EHB overdensity tied to NGC 6971, without needing an ad hoc and anomalous mass-loss prescription.