Rejuvenated accretors have less bound envelopes: Impact of Roche lobe overflow on subsequent common envelope events. (arXiv:2206.15338v3 [astro-ph.SR] UPDATED)

Rejuvenated accretors have less bound envelopes: Impact of Roche lobe overflow on subsequent common envelope events. (arXiv:2206.15338v3 [astro-ph.SR] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Renzo_M/0/1/0/all/0/1">M. Renzo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zapartas_E/0/1/0/all/0/1">E. Zapartas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Justham_S/0/1/0/all/0/1">S. Justham</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Breivik_K/0/1/0/all/0/1">K. Breivik</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lau_M/0/1/0/all/0/1">M. Lau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Farmer_R/0/1/0/all/0/1">R. Farmer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cantiello_M/0/1/0/all/0/1">M. Cantiello</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Metzger_B/0/1/0/all/0/1">B. D. Metzger</a>

Common-envelope (CE) evolution is an outstanding open problem in stellar
evolution, critical to the formation of compact binaries including
gravitational-wave sources. In the “classical” isolated binary evolution
scenario for double compact objects, the CE is usually the second mass transfer
phase. Thus, the donor star of the CE is the product of a previous binary
interaction, often stable Roche-lobe overflow (RLOF). Because of the accretion
of mass during the first RLOF, the main-sequence core of the accretor star
grows and is “rejuvenated”. This modifies the core-envelope boundary region
and decreases significantly the envelope binding energy for the remaining
evolution. Comparing accretor stars from self-consistent binary models to stars
evolved as single, we demonstrate that the rejuvenation can lower the energy
required to eject a CE by $sim 42-96%$ for both black hole and neutron star
progenitors, depending on the evolutionary stage and final orbital separation.
Therefore, binaries experiencing first stable mass transfer may more easily
survive subsequent CE events and result in possibly wider final separations
compared to current predictions. Despite their high mass, our accretors also
experience extended “blue loops”, which may have observational consequences
for low-metallicity stellar populations and asteroseismology.

Common-envelope (CE) evolution is an outstanding open problem in stellar
evolution, critical to the formation of compact binaries including
gravitational-wave sources. In the “classical” isolated binary evolution
scenario for double compact objects, the CE is usually the second mass transfer
phase. Thus, the donor star of the CE is the product of a previous binary
interaction, often stable Roche-lobe overflow (RLOF). Because of the accretion
of mass during the first RLOF, the main-sequence core of the accretor star
grows and is “rejuvenated”. This modifies the core-envelope boundary region
and decreases significantly the envelope binding energy for the remaining
evolution. Comparing accretor stars from self-consistent binary models to stars
evolved as single, we demonstrate that the rejuvenation can lower the energy
required to eject a CE by $sim 42-96%$ for both black hole and neutron star
progenitors, depending on the evolutionary stage and final orbital separation.
Therefore, binaries experiencing first stable mass transfer may more easily
survive subsequent CE events and result in possibly wider final separations
compared to current predictions. Despite their high mass, our accretors also
experience extended “blue loops”, which may have observational consequences
for low-metallicity stellar populations and asteroseismology.

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