SNhunt151: an explosive event inside a dense cocoon



: Elias-Rosa N, Benetti S, Cappellaro E, Pastorello A, Terreran G, Morales-Garoffolo A, Howerton SC, Valenti S, Kankare E, Drake AJ, Djorgovski SG, Tomasella L, Tartaglia L, Kangas T, Ochner P, Filippenko AV, Ciabattari F, Geier S, Howell DA, Isern J, Leonini S, Pignata G, Turatto M, Turatto M

Publisher: OXFORD UNIV PRESS

: 2018

: Monthly Notices of the Royal Astronomical Society

: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

: MON NOT R ASTRON SOC

: 475

: 2

: 2614

: 2631

: 18

: 0035-8711

DOI: https://doi.org/10.1093/mnras/sty009

: https://research.utu.fi/converis/portal/detail/Publication/30673600


SNhunt151 was initially classified as a supernova (SN) impostor (nonterminal outburst of a massive star). It exhibited a slow increase in luminosity, lasting about 450 d, followed by a major brightening that reaches M-V approximate to -18 mag. No source is detected to M-V greater than or similar to -13 mag in archival images at the position of SNhunt151 before the slow rise. Low-to-mid-resolution optical spectra obtained during the pronounced brightening show very little evolution, being dominated at all times by multicomponent Balmer emission lines, a signature of interaction between the material ejected in the new outburst and the pre-existing circumstellar medium. We also analysed mid-infrared images from the Spitzer Space Telescope, detecting a source at the transient position in 2014 and 2015. Overall, SNhunt151 is spectroscopically a Type IIn SN, somewhat similar to SN 2009ip. However, there are also some differences, such as a slow pre-discovery rise, a relatively broad light-curve peak showing a longer rise time (similar to 50 d), and a slower decline, along with a negligible change in the temperature around the peak (T <= 10(4) K). We suggest that SNhunt151 is the result of an outburst, or an SN explosion, within a dense circumstellar nebula, similar to those embedding some luminous blue variables like eta Carinae and originating from past mass-loss events.

Last updated on 2024-26-11 at 21:45