Common-envelope evolution — where a star is engulfed by a companion — is critical for, e.g., the formation of gravitational-wave sources. However, it remains poorly understood theoretically, and it has been extremely challenging to identify observable signatures. In this talk, I will show that for systems involving a neutron star, the hypothesized super-Eddington accretion onto the neutron star produces MeV-range, months-long neutrino signals within reach of present and planned detectors.
While there are substantial uncertainties on the rate of such event and the total neutrino luminosity, this signal can only be found if dedicated new searches are developed. If detected, the neutrino signal would lead to significant new insights into the astrophysics of common-envelope evolution and, potentially, into particle physics too.