Medler, K.Mazzali, P.A.Teffs, J.Ashall, C.Anderson, J.P.Arcavi, I.Benetti, S.Bostroem, K.A.Burke, J.Cai, Y.-Z.Charalampopoulos, P.Elias Rosa, N.Ergon, M.Galbany, L.Gromadzki, M.Hiramatsu, D.Howell, D.A.Inserra, C.Lundqvist, P.McCully, C.Müller Bravo, T.Newsome, M.Nicholl, M.Gonzalez, E. PadillaParaskeva, E.Pastorello, A.Pellegrino, C.Pessi, P.J.Reguitti, A.Reynolds, T.M.Roy, R.Terreran, G.Tomasella, L.Young, D.R.2023-11-162023-11-162022-07-01Monthly Notices of the Royal Astronomical Society, Volume 513, Issue 4, Pages 5540 - 5558, 1 July 20220035-8711https://repositorio.unab.cl/xmlui/handle/ria/53986Indexación: Scopus.The ultraviolet (UV) and near-infrared (NIR) photometric and optical spectroscopic observations of SN 2020acat covering ∼250 d after explosion are presented here. Using the fast rising photometric observations, spanning from the UV to NIR wavelengths, a pseudo-bolometric light curve was constructed and compared to several other well-observed Type IIb supernovae (SNe IIb). SN 2020acat displayed a very short rise time reaching a peak luminosity of Log10(L) = 42.49 ± 0.17 erg s-1 in only ∼14.6 ± 0.3 d. From modelling of the pseudo-bolometric light curve, we estimated a total mass of 56Ni synthesized by SN 2020acat of MNi = 0.13 ± 0.03 M⊙, with an ejecta mass of Mej = 2.3 ± 0.4 M⊙ and a kinetic energy of Ek = 1.2 ± 0.3 × 1051 erg. The optical spectra of SN 2020acat display hydrogen signatures well into the transitional period (≳ 100 d), between the photospheric and the nebular phases. The spectra also display a strong feature around 4900 Å that cannot be solely accounted for by the presence of the Fe ii 5018 line. We suggest that the Fe ii feature was augmented by He i 5016 and possibly by the presence of N ii 5005. From both photometric and spectroscopic analysis, we inferred that the progenitor of SN 2020acat was an intermediate-mass compact star with an MZAMS of 15-20 M⊙. © 2022 The Author(s).enSupernovae: generalSupernovae: individual: SN 2020acatArtículoCC BY 4.0 DEED Atribución 4.0 Internacional10.1093/mnras/stac1192