Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Erik C. Kool
Joel Johansson
Jesper Sollerman
Javier Moldón
Takashi J. Moriya
Steve Schulze
Laura Chomiuk
Chelsea Harris
Miguel Pérez-Torres
Seppo Mattila
Peter Lundqvist
Matthew Graham
Sheng Yang
Daniel A. Perley
Nora Linn Strotjohann
Christoffer Fremling
Avishay Gal-Yam
Jeremy Lezmy
Kate Maguire
Conor Omand
Abstract： Type Ia supernovae are thought to be carbon-oxygen white dwarf stars that explode after accreting material from a companion star, but despite extensive studies the nature of the companion star is still poorly understood, as is the explosion mechanism. In the single degenerate scenario, the companion is a non-degenerate star that loses material through winds and/or binary interaction, and a few Type Ia supernovae have shown evidence for hydrogen-rich circumstellar material. We present here the study of SN 2020eyj, a unique Type Ia supernova showing delayed interaction with helium-rich, but hydrogen-poor, circumstellar material. This material surrounding SN 2020eyj is revealed by its unusual light curve and infrared emission, narrow helium emission lines and, for the first time ever in a Type Ia supernova, also a radio counterpart. The circumstellar material likely originates from the companion star, providing the first direct evidence for a, so far hypothesized, single degenerate progenitor system composed of a white dwarf and a helium donor star.
Peer Review Status:
Awaiting Review
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