Speaker
Description
To reveal the nature of Type Ia supernovae (SNe Ia), one approach is to identify the surviving companions of their progenitor systems near the explosion centers of the SN remnants (SNRs). In DEM L71, a star was previously reported as a potential surviving companion of the SN Ia because of its peculiar radial velocity, offset by more than 2.5$\sigma$ from the mean of the underlying stellar population. However, this star lies at a relatively large distance (13.2\arcsec)
from the previously estimated SN explosion site, and the positional uncertainty of that site was not quantified. If it were the surviving companion, it would require an unusually large proper motion. In this study, we apply a robust machine-learning–based framework to re-assess the explosion site and estimate the site's positional uncertainty to be about 9.3\arcsec (3$\sigma$). This result clearly shows that the candidate star lies well within the primary search radius (5.7\arcsec) from the explosion site, greatly reducing the inferred excessive proper motion. Furthermore, by comparing the star’s photometric properties with evolutionary models of surviving red-giant (RG) companions in the color–magnitude diagrams, we find that its characteristics are consistent with those expected for a post-He-flash RG companion, although ordinary RG companions cannot be ruled out. Finally, based on the analysis of the physical structure of DEM L71, we estimate the mass of the circumstellar medium within the remnant to be $\sim$ 0.1--0.2 $M_\odot$, supporting a single-degenerate origin.
| Participate the oral/poster presentation award competition | Yes |
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