천문학회보 (The Bulletin of The Korean Astronomical Society)
- 제46권1호
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- Pages.55.2-56
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- 2021
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- 1226-2692(pISSN)
Intensive Monitoring Survey of Nearby Galaxies (IMSNG) : Constraints on the progenitor system of a normal Type Ia SN 2019ein from its light curve at the early phase
- Lim, Gu (SNU Astronomy Research Center, Seoul National University) ;
- Im, Myungshin (SNU Astronomy Research Center, Seoul National University) ;
- Kim, Dohyeong (Department of Earth Sciences, Pusan National University) ;
- Paek, Gregory S.H (SNU Astronomy Research Center, Seoul National University) ;
- Choi, Changsu (SNU Astronomy Research Center, Seoul National University) ;
- Kim, Sophia (SNU Astronomy Research Center, Seoul National University) ;
- Hwang, Sungyong (SNU Astronomy Research Center, Seoul National University)
- 발행 : 2021.04.13
초록
The progenitor of Type Ia supernovae (SNe Ia) is mainly believed to be a close binary system of acarbon-oxygen white dwarf (CO WD) and non-degenerate companion (single degenerate) or another WD (double degenerate). However, it is unclear which system is more prevalent. Here, we present a high cadence optical/Near-IR light curve of normal but slightly faint type Ia SN 2019ein from IMSNG project. We fit the early light curve (t <+8.3 days from the first detection) with various models to find the shock-heated cooling emission from SN ejecta-companion interaction. No significant shock-heated cooling emission is found, from which we constrain the progenitor star size as the following. The upper limit (Rupper,*) of the companion size in R-band is ~0.2R⊙ when forcing the first light time (tfl) to have one value and ~0.9R⊙ when using the mean value of tfl from the fitting in each band. Assuming the source of the I-band curve is almost powered from the radioactive decay, we obtained Rupper,*~1.2R⊙. The early B-V color curve is in agreement with the model color curve of the 2M⊙ main sequence companion. These results allow us to at least rule out large stars like red giants as a companion star of the binary progenitor system of this supernova. B-R and V-R color do not show any significant signs of a red bump, which shows a thin helium shell (MHe<0.1M⊙) for the sub-Mch WD (double detonation model). In addition, we estimated the distance to NGC 5353 as 37.098±0.028Mpc.
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