TESS early light curves of type Ia Supernovae

For assumptions about the SN properties and the observer viewing angle (ejecta mass of 1.4M{sun}, expansion velocity of 104km/s, opacity of 0.2cm^2^/g, and viewing angle of 45{deg}) and a further assumption that any companion stars would be in Roche lobe overflow, it is possible to place upper limits on the radii of any companion stars. Six of the nine SNe had complete coverage of the early-time light curves, and we placed upper limits on the radii of companion stars of <~32R{sun} for these SNe, <~20R{sun} for five of the six, and <~4R{sun} for two of the six.

The small sample size did not allow us to put limits on the occurrence rate of companion stars in the progenitors of SNe Ia. However, we expect that TESS observed enough SNe in its two-year primary mission (26 sectors) to either detect the signature of a large companion (R>20R{sun}) or constrain the occurrence rate of such systems, at least for the fiducial SN properties adopted here. We also show that TESS is capable of detecting emission from a 1R{sun} companion for an SN Ia within 50Mpc and has a reasonable chance of doing so after about six years.