SN 2021gno: a calcium-rich transient with double-peaked light curves

K. Ertini*, G. Folatelli, L. Martinez, M. C. Bersten, J. P. Anderson, C. Ashall, E. Baron, S. Bose, P. J. Brown, C. Burns, J. M. Derkacy, L. Ferrari, L. Galbany, E. Hsiao, S. Kumar, J. Lu, P. Mazzali, N. Morrell, M. Orellana, P. J. PessiM. M. Phillips, A. L. Piro, A. Polin, M. Shahbandeh, B. J. Shappee, M. Stritzinger, N. B. Suntzeff, M. Tucker, N. Elias-Rosa, H. Kuncarayakti, C. P. Gutiérrez, A. Kozyreva, T. E. Müller-Bravo, T. W. Chen, J. T. Hinkle, A. V. Payne, P. Székely, T. Szalai, B. Barna, R. Könyves-Tóth, D. Bánhidi, I. B. Bíró, I. Csányi, L. Kriskovits, A. Pál, Z. Szabó, R. Szakáts, K. Vida, J. Vinkó, M. Gromadzki, L. Harvey, M. Nicholl, E. Paraskeva, D. R. Young, B. Englert

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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 languageEnglish
Pages (from-to)279-298
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - 1 Nov 2023
Externally publishedYes


  • stars: massive
  • supernovae: general
  • supernovae: individual: SN 2021gno


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