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Post-common envelope binary systems experiencing helium-shell-driven stable mass transfer

Published version
Peer-reviewed

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Authors

Halabi, GM 
Izzard, RG 
Tout, CA 

Abstract

We evolve stellar models to study the common envelope (CE) interaction of an early asymptotic giant branch star of initial mass 5M with a companion star of mass ranging from 0.1 to 2M. We model the CE as a fast stripping phase in which the primary experiences rapid mass loss and loses about 80 per cent of its mass. The post-CE remnant is then allowed to thermally readjust during a Roche-lobe overflow (RLOF) phase and the final binary system and its orbital period are investigated. We find that the post-CE RLOF phase is long enough to allow nuclear burning to proceed in the helium shell. By the end of this phase, the donor is stripped of both its hydrogen and helium and ends up as carbon-oxygen white dwarf of mass about 0.8M. We study the sensitivity of our results to initial conditions of different companion masses and orbital separations at which the stripping phase begins. We find that the companion mass affects the final binary separation and that helium-shell burning causes the star to refill its Roche lobe leading to post-CE RLOF. Our results show that double mass transfer in such a binary interaction is able to strip the helium and hydrogen layers from the donor star without the need for any special conditions or fine tuning of the binary parameters.

Description

Keywords

binaries: general, stars: evolution, stars: interiors, stars: mass-loss

Journal Title

Monthly Notices of the Royal Astronomical Society

Conference Name

Journal ISSN

0035-8711
1365-2966

Volume Title

480

Publisher

Oxford University Press (OUP)
Sponsorship
Science and Technology Facilities Council (ST/M003892/1)