Symbiotic Stars (Including T Corona Borealis) Are Not Immediate Progenitors of Normal Type Ia Supernovae

TL;DR

The paper addresses whether symbiotic stars are the immediate progenitors of normal Type Ia supernovae by compiling seven independent observational tests—direct ex-companion searches, pre-explosion imaging, nebular H and He lines, radio and X-ray ejecta-wind interactions, and the Kasen effect—applied to up to 189 normal SNIa. Across these diverse, high-sensitivity probes, no red-giant companions or strong winds are detected, yielding stringent upper limits such as $<0.53\%$ for the symbiotic-progenitor fraction. The findings imply that symbiotic-star channels contribute negligibly to the normal SNIa population, challenging the viability of the SD symbiotic scenario as a dominant progenitor path. This has significant implications for understanding SNIa progenitors and informs population synthesis and cosmological use of SNIa as standard candles.

Abstract

A popular solution to the Type Ia supernova (SNIa) progenitor problem is that the immediate progenitors are symbiotic star systems. This solution requires that the companion star of the exploding white dwarf must be a red giant star with a heavy stellar wind. This has been tested for 189 normal SNIa, with all tested systems being proven to not have the required red giant: (A) Zero-out-of-9 normal type Ia supernova remnants have any red giant ex-companion star near the center with limits of $M_V$$>$0.0. (B) Zero-out-of-2 normal SNIa in nearby galaxies have any red giant at the position as seen in archival pre-eruption images by HST to limits of $M_V$$>$0.0. (C and D) Zero-out-of-111 normal SNIa have any detected hydrogen or helium emission lines in their eruption spectra, with limits on entrained gas of $M_{\rm H}$$<$0.22 and $M_{\rm He}$$<$0.07 M$_{\odot}$, which is the minimum mass lost by a red giant in a nearby blastwave. (E and F) Zero-out-of-9 nearby normal SNIa were detected in the radio or X-rays, as required from the ejecta/wind impact, to limits of $\dot{M}_{\rm wind}$$<$3$\times$$10^{-9}$ M$_{\odot}$ yr$^{-1}$. (G) Zero-out-of-$\sim$69 normal SNIa display any brightening in the first few days to limits of $M_V$$>$$-$18, as required for a red giant companion when we are looking down its shadowcone. With zero-out-of-189 normal SNIa having any possibility of having a red giant companion, the fraction of SNIa with symbiotic progenitors is $<$0.53%. The overwhelming conclusion is that normal SNIa are not from symbiotic-progenitors in any measurable fraction.