Cai, Y.-Z.Pastorello, A.Fraser, M.Botticella, M. T.Elias-Rosa, N.Wang, L.-Z.Kotak, R.Benetti, S.Cappellaro, E.Turatto, M.Reguitti, A.Mattila, S.Smartt, S. J.Ashall, C.Benitez, S.Chen, T.-W.Harutyunyan, A.Kankare, E.Lundqvist, P.Mazzali, P. A.Morales-Garoffolo, A.Ochner, P.Pignata, G.Prentice, S. J.Reynolds, T. M.Shu, X.-W.Stritzinger, M. D.Tartaglia, L.Terreran, G.Tomasella, L.Valenti, S.Valerin, G.Wang, G.-J.Wang, X.-F.Borsato, L.Callis, E.Cannizzaro, G.Chen, S.Congiu, E.Ergon, M.Galbany, L.Gal-Yam, A.Gao, X.Gromadzki, M.Holmbo, S.Huang, F.Inserra, C.Itagaki, K.Kostrzewa-Rutkowska, Z.Maguire, K.Margheim, S.Moran, S.Onori, F.Sagués Carracedo, A.Smith, K. W.Sollerman, J.Somero, A.Wang, B.Young, D. R.2022-06-142022-06-142021-10-01Astronomy and Astrophysics Volume 6541 October 2021 Article number A1570004-6361https://repositorio.unab.cl/xmlui/handle/ria/22818Indexación ScopusWe present the spectroscopic and photometric study of five intermediate-luminosity red transients (ILRTs), namely AT 2010dn, AT 2012jc, AT 2013la, AT 2013lb, and AT 2018aes. They share common observational properties and belong to a family of objects similar to the prototypical ILRT SN 2008S. These events have a rise time that is less than 15 days and absolute peak magnitudes of between-11.5 and-14.5 mag. Their pseudo-bolometric light curves peak in the range 0.5-9.0 × 1040 erg s-1 and their total radiated energies are on the order of (0.3-3) × 1047 erg. After maximum brightness, the light curves show a monotonic decline or a plateau, resembling those of faint supernovae IIL or IIP, respectively. At late phases, the light curves flatten, roughly following the slope of the 56Co decay. If the late-time power source is indeed radioactive decay, these transients produce 56Ni masses on the order of 10-4 to 10-3 M⊙. The spectral energy distribution of our ILRT sample, extending from the optical to the mid-infrared (MIR) domain, reveals a clear IR excess soon after explosion and non-negligible MIR emission at very late phases. The spectra show prominent H lines in emission with a typical velocity of a few hundred km s-1, along with Ca II features. In particular, the [Ca II] λ7291,7324 doublet is visible at all times, which is a characteristic feature for this family of transients. The identified progenitor of SN 2008S, which is luminous in archival Spitzer MIR images, suggests an intermediate-mass precursor star embedded in a dusty cocoon. We propose the explosion of a super-asymptotic giant branch star forming an electron-capture supernova as a plausible explanation for these events.enStars: AGB and post-AGBStars: Mass-lossSupernovae: GeneralArtículoAttribution 4.0 International (CC BY 4.0)10.1051/0004-6361/202141078