Why are surviving companion stars absent near Type Ia remnants? · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
Why are surviving companion stars absent near Type Ia remnants?
Plain
If a white dwarf explodes while pulling gas from a normal star, that companion should survive and be seen near the center of the debris. Deep searches of young remnants have found no such star.
Precise · changed · core
Revision 1: Single-degenerate models predict a surviving donor at the center of young SN Ia remnants (for example Tycho, Kepler, SN 1006, SNR 0509-67.5), inflated and overluminous for $1e3 \text{ to } 1e4\,\mathrm{yr}$ and moving at a few hundred km/s; deep HST searches exclude such stars in several remnants. Explain the nondetections (double-degenerate origin, spin-up/spin-down delay that lets the donor shrink, or misidentified models), and reconcile the observed hypervelocity white dwarfs moving above $1000\,\mathrm{km/s}$ with the number expected if double detonations eject surviving companions.
Revision 2: Single-degenerate models predict a surviving donor at the center of young SN Ia remnants (for example Tycho, Kepler, SN 1006, SNR 0509-67.5), inflated and overluminous for $10^{3} \text{ to } 10^{4}\,\mathrm{yr}$ and moving at a few hundred km/s; deep HST searches exclude such stars in several remnants. Explain the nondetections (double-degenerate origin, spin-up/spin-down delay that lets the donor shrink, or misidentified models), and reconcile the observed hypervelocity white dwarfs moving above $1000\,\mathrm{km/s}$ with the number expected if double detonations eject surviving companions.
Settled by
A complete census of hypervelocity runaway white dwarfs from Gaia compared with the predicted ejection rate, together with deep companion limits in a larger set of Ia remnants.
Kind
phenomenon
Answer type
mechanism
References
(empty)
Literature status
open
Status note
Hypervelocity runaway white dwarfs found in Gaia data since 2018 are candidate survivors of double detonations; whether their numbers match the SN Ia rate is debated.
Posed since
(empty)

Decisions