Abstract

Contributed Talk - Splinter CloseBinaries   (MW-0250)

Unveiling luminous red novae from 3D radiation-hydrodynamic simulations of common-envelope evolution

Mike Lau et al.
Heidelberg Institute for Theoretical Studies

Binary stars that merge or undergo common-envelope evolution are believed to produce a class of transients known as luminous red novae. These transients exhibit weeks- to month-long plateaus and peak luminosities roughly between those of supernovae and classical novae. We present synthetic photometry from one of the first 3D radiation-hydrodynamic simulations of common-envelope evolution involving a 12 solar mass red supergiant (Lau et al. 2025). The model produces a weeks-long transient whose duration, peak luminosity, and colour evolution broadly match those of known red novae. We further show that this emission cannot be reproduced by an adiabatic simulation, which instead predicts that the giant star dims as it becomes obscured by cool, toroidal ejecta.