Can common-envelope ejection produce tight merging black-hole binaries? · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
Can common-envelope ejection produce tight merging black-hole binaries?
Plain
Many merging pairs are thought to have shrunk when one star swelled and engulfed its companion, which spiraled in and blew off the shared envelope; whether the envelope can actually be thrown off and leave a tight enough orbit has not been shown.
Precise · changed · core
Revision 1: In common-envelope evolution the orbital energy released during inspiral must unbind the donor envelope, conventionally parametrized by $\alpha_{\mathrm{CE}}\times\lambda$. Determine from $3D$ hydrodynamics (with recombination energy, jets and post-plunge evolution) whether envelopes of $15\ \text{to}\ 40\ M_{\mathrm{sun}}$ red supergiant donors are fully ejected, and whether final separations of a few $R_{\mathrm{sun}}$, small enough to merge by gravitational waves within $1.4e10\ \mathrm{yr}$, result. Answer: final separation and ejected mass versus donor mass and radius, and the implied share of mergers from this route versus stable mass transfer.
Revision 2: In common-envelope evolution the orbital energy released during inspiral must unbind the donor envelope, conventionally parametrized by $\alpha_{\mathrm{CE}}\times\lambda$. Determine from $3D$ hydrodynamics (with recombination energy, jets and post-plunge evolution) whether envelopes of $15\ \text{to}\ 40\ M_{\mathrm{sun}}$ red supergiant donors are fully ejected, and whether final separations of a few $R_{\mathrm{sun}}$, small enough to merge by gravitational waves within $1.4 \times 10^{10}\ \mathrm{yr}$, result. Answer: final separation and ejected mass versus donor mass and radius, and the implied share of mergers from this route versus stable mass transfer.
Settled by
3D simulations followed to full envelope ejection or merger for massive donors, calibrated on observed post-common-envelope binaries.
Kind
well-posed
Answer type
value
References
(empty)
Literature status
open
Status note
(empty)
Posed since
1976

Decisions