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Abstract We present photometric and spectroscopic observations of SN 2020bio, a double-peaked Type IIb supernova (SN) discovered within a day of explosion, primarily obtained by Las Cumbres Observatory and Swift. SN 2020bio displays a rapid and long-lasting initial decline throughout the first week of its light curve, similarly to other well-studied Type IIb SNe. This early-time emission is thought to originate from the cooling of the extended outer hydrogen-rich (H-rich) envelope of the progenitor star that is shock heated by the SN explosion. We compare SN 2020bio to a sample of other double-peaked Type IIb SNe in order to investigate its progenitor properties. Analytical model fits to the early-time emission give progenitor radius (≈100–1500R⊙) and H-rich envelope mass (≈0.01–0.5M⊙) estimates that are consistent with other Type IIb SNe. However, SN 2020bio displays several peculiarities, including (1) weak H spectral features indicating a greater amount of mass loss than other Type IIb progenitors; (2) an underluminous secondary light-curve peak that implies a small amount of synthesized56Ni (MNi≈0.02M⊙); and (3) low-luminosity nebular [Oi] and interaction-powered nebular features. These observations are more consistent with a lower-mass progenitor (MZAMS≈ 12M⊙) that was stripped of most of its H-rich envelope before exploding. This study adds to the growing diversity in the observed properties of Type IIb SNe and their progenitors.
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Characterizing the Rapid Hydrogen Disappearance in SN 2022crv: Evidence of a Continuum between Type Ib and IIb Supernova Properties
Abstract We present optical and near-infrared (NIR) observations of SN 2022crv, a stripped-envelope supernova in NGC 3054, discovered within 12 hr of explosion by the Distance Less Than 40 Mpc Survey. We suggest that SN 2022crv is a transitional object on the continuum between Type Ib supernovae (SNe Ib) and Type IIb supernovae (SNe IIb). A high-velocity hydrogen feature (∼ −20,000 to −16,000 km s−1) was conspicuous in SN 2022crv at early phases, and then quickly disappeared. We find that a hydrogen envelope of ∼10−3M⊙can reproduce the observed behavior of the hydrogen feature. The lack of early envelope cooling emission implies that SN 2022crv had a compact progenitor with an extremely low amount of hydrogen. A nebular spectral analysis shows that SN 2022crv is consistent with the explosion of a He star with a final mass of ∼4.5–5.6M⊙that evolved from a ∼16 to 22M⊙zero-age main-sequence star in a binary system with ∼1.0–1.7M⊙of oxygen finally synthesized in the core. In order to retain such a small amount of hydrogen, the initial orbital separation of the binary system is likely larger than ∼1000R⊙. The NIR spectra of SN 2022crv show a unique absorption feature on the blue side of the Heiline at ∼1.005μm. This is the first time such a feature has been observed in SNe Ib/IIb, and it could be due to Sr II. Further detailed modeling of SN 2022crv can shed light on the progenitor and the origin of the mysterious absorption feature in the NIR.
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- PAR ID:
- 10549687
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 974
- Issue:
- 2
- ISSN:
- 0004-637X
- Format(s):
- Medium: X Size: Article No. 316
- Size(s):
- Article No. 316
- Sponsoring Org:
- National Science Foundation
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