Bridging between Type IIb and Ib Supernovae: SN IIb 2022crv with a Very Thin Hydrogen Envelope
Abstract
We present optical, near-infrared, and radio observations of supernova (SN) SN IIb 2022crv. We show that it retained a very thin H envelope and transitioned from an SN IIb to an SN Ib; prominent Hα seen in the pre-maximum phase diminishes toward the post-maximum phase, while He I lines show increasing strength. SYNAPPS modeling of the early spectra of SN 2022crv suggests that the absorption feature at 6200 Å is explained by a substantial contribution of Hα together with Si II, as is also supported by the velocity evolution of Hα. The light-curve evolution is consistent with the canonical stripped-envelope SN subclass but among the slowest. The light curve lacks the initial cooling phase and shows a bright main peak (peak M V = -17.82 ± 0.17 mag), mostly driven by radioactive decay of 56Ni. The light-curve analysis suggests a thin outer H envelope (M env ~ 0.05 M ⊙) and a compact progenitor (R env ~ 3 R ⊙). An interaction-powered synchrotron self-absorption model can reproduce the radio light curves with a mean shock velocity of 0.1c. The mass-loss rate is estimated to be in the range of (1.9-2.8) × 10-5 M ⊙ yr-1 for an assumed wind velocity of 1000 km s-1, which is on the high end in comparison with other compact SNe IIb/Ib. SN 2022crv fills a previously unoccupied parameter space of a very compact progenitor, representing a beautiful continuity between the compact and extended progenitor scenario of SNe IIb/Ib.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2023
- DOI:
- 10.3847/1538-4357/acfa94
- arXiv:
- arXiv:2309.07463
- Bibcode:
- 2023ApJ...957..100G
- Keywords:
-
- Photometry;
- Spectroscopy;
- Supernovae;
- Type Ib supernovae;
- Radio astronomy;
- 1234;
- 1558;
- 1668;
- 1729;
- 1338;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- The paper contains 20 figures and 9 tables. Accepted for publication in The Astrophysical Journal (ApJ)