The Early Light Curve of SN 2023bee: Constraining Type Ia Supernova Progenitors the Apian Way

TL;DR

This study presents early observations of SN 2023bee revealing a shock interaction consistent with a main-sequence companion, providing insights into the progenitor system of Type Ia supernovae.

Contribution

It provides the earliest photometric and spectroscopic data of SN 2023bee, constrains the nature of its binary companion, and tests various explosion models against observed light curves.

Findings

Early optical and UV excess consistent with a main-sequence companion shock

Spectral signatures of unburned carbon detected in early spectra

Radio observations limit the companion to a main-sequence star, excluding red giants

Abstract

We present very early photometric and spectroscopic observations of the Type Ia supernova (SN Ia) 2023bee, starting about 8 hr after the explosion, which reveal a strong excess in the optical and nearest UV (U and UVW1) bands during the first several days of explosion. This data set allows us to probe the nature of the binary companion of the exploding white dwarf and the conditions leading to its ignition. We find a good match to the Kasen model in which a main-sequence companion star stings the ejecta with a shock as they buzz past. Models of double detonations, shells of radioactive nickel near the surface, interaction with circumstellar material, and pulsational delayed detonations do not provide good matches to our light curves. We also observe signatures of unburned material, in the form of carbon absorption, in our earliest spectra. Our radio nondetections place a limit on the mass-loss rate from the putative companion that rules out a red giant but allows a main-sequence star. We discuss our results in the context of other similar SNe Ia in the literature.