Massive stars exploding in a He-rich circumstellar medium - II. The transitional case of SN 2005la

: Pastorello A, Quimby RM, Smartt SJ, Mattila S, Navasardyan H, Crockett RM, Elias-Rosa N, Mondol P, Wheeler JC, Young DR

Publisher: WILEY-BLACKWELL PUBLISHING, INC

: 2008

Monthly Notices of the Royal Astronomical Society

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

: MON NOT R ASTRON SOC

: 389

: 1

: 131

: 140

: 10

: 0035-8711

DOI: https://doi.org/10.1111/j.1365-2966.2008.13603.x

We present photometric and spectroscopic data of the peculiar SN 2005la, an object which shows an optical light curve with some luminosity fluctuations and spectra with comparably strong narrow hydrogen and helium lines, probably of circumstellar nature. The increasing full width at half-maximum velocity of these lines is indicative of an acceleration of the circumstellar material. SN 2005la exhibits hybrid properties, sharing some similarities with both Type IIn supernovae and 2006jc-like (Type Ibn) events. We propose that the progenitor of SN 2005la was a very young Wolf-Rayet (WN-type) star which experienced mass ejection episodes shortly before core collapse.