Abstract
We present extensive ultraviolet (UV) and optical photometric and optical spectroscopic follow-up of supernova (SN) 2021gno by the 'Precision Observations of Infant Supernova Explosions' (POISE) project, starting less than 2 d after the explosion. Given its intermediate luminosity, fast photometric evolution, and quick transition to the nebular phase with spectra dominated by [Ca ii] lines, SN 2021gno belongs to the small family of Calcium-rich transients. Moreover, it shows double-peaked light curves, a phenomenon shared with only four other Calcium-rich events. The projected distance from the centre of the host galaxy is not as large as other objects in this family. The initial optical light-curve peaks coincide with a very quick decline of the UV flux, indicating a fast initial cooling phase. Through hydrodynamical modelling of the bolometric light curve and line velocity evolution, we found that the observations are compatible with the explosion of a highly stripped massive star with an ejecta mass of and a 56Ni mass of 0.024 M⊙. The initial cooling phase (first light-curve peak) is explained by the presence of an extended circumstellar material comprising ∼ with an extension of. We discuss if hydrogen features are present in both maximum-light and nebular spectra, and their implications in terms of the proposed progenitor scenarios for Calcium-rich transients.
Original language | English |
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Pages (from-to) | 279-298 |
Number of pages | 20 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 526 |
Issue number | 1 |
DOIs | |
State | Published - 1 Nov 2023 |
Externally published | Yes |
Keywords
- stars: massive
- supernovae: general
- supernovae: individual: SN 2021gno