2007ApJ...659.1536R

M85 OT2006-1 is the latest and most brilliant addition to the small group of known luminous red novae (LRNe). An identifying characteristic of the previously detected events (M31 RV, V4332 Sgr, and V838 Mon) was a spectral redward evolution connected with an emerging infrared component following the optical decay. Here we report on the discovery of a similar feature in Keck NIRC and Spitzer photometry of M85 OT2006-1 6 months posteruption. We find that its 2.1-22 µm spectral energy distribution is best described by a blackbody with effective temperature T_eff=950±150 K and bolometric luminosity L=2.9^+0.4_–0.5x10⁵ L_☉. Assuming spherical geometry, the blackbody effective radius, R=2.0^+0.6_–0.4x10⁴ R_☉, and corresponding expansion velocity, v=870⁺²⁶⁰_–180 km/s, are remarkably similar to the properties of M31 RV 70 days after its eruption. Furthermore, we propose a search strategy for LRNe in the local universe making use of the longevity of their infrared excess emission and discuss the expected number of events in the Spitzer Infrared Nearby Galaxies Survey.