EDP Sciences

Vol. 542
In section 7. Stellar structure and evolution

Lithium production in the merging of white dwarf stars

by R. Longland, P. Lorén-Aguilar, J. José, E. García-Berro, L. G. Althaus, A&A 542, A117

R Coronae Borealis stars are hydrogen-poor giant stars. Two scenarios for their origin are being discussed: a late final He-shell flash after the star left the asymptotic giant branch, and the merging of two white dwarfs, one of which has a He core. The detection of Li in some R CrB stars was used as a strong argument for the final-flash scenario. This article presents nycleosynthesis calculations of a merger event. The authors conclude that it is possible to produce the observed Li abundances, which means that the detection of Li does not rule out a merger origin.