학술논문
SN 2016coi/ASASSN-16fp: An example of residual helium in a type Ic supernova?
Document Type
Working Paper
Author
Prentice, S. J.; Ashall, C.; Mazzali, P. A.; Zhang, J. -J.; James, P. A.; Wang, X. -F.; Vinko, J.; Percival, S.; Short, L.; Piascik, A.; Huang, F.; Mo, J.; Rui, L. -M.; Wang, J. -G.; Xiang, D. -F.; Xin, Y. -X.; Yi, W. -M.; Yu, X. -G.; Zhai, Q.; Zhang, T. -M.; Hosseinzadeh, G.; Howell, D. A.; McCully, C.; Valenti, S.; Cseh, B.; Hanyecz, O.; Kriskovics, L.; Pal, A.; Sarneczky, K.; Sodor, A.; Szakats, R.; Szekely, P.; Varga-Verebelyi, E.; Vida, K.; Bradac, M.; Reichart, D. E.; Sand, D.; Tartaglia, L.
Source
Subject
Language
Abstract
The optical observations of Ic-4 supernova (SN) 2016coi/ASASSN-16fp, from $\sim 2$ to $\sim450$ days after explosion, are presented along with analysis of its physical properties. The SN shows the broad lines associated with SNe Ic-3/4 but with a key difference. The early spectra display a strong absorption feature at $\sim 5400$ \AA\ which is not seen in other SNe~Ic-3/4 at this epoch. This feature has been attributed to He I in the literature. Spectral modelling of the SN in the early photospheric phase suggests the presence of residual He in a C/O dominated shell. However, the behaviour of the He I lines are unusual when compared with He-rich SNe, showing relatively low velocities and weakening rather than strengthening over time. The SN is found to rise to peak $\sim 16$ d after core-collapse reaching a bolometric luminosity of Lp $\sim 3\times10^{42}$ \ergs. Spectral models, including the nebular epoch, show that the SN ejected $2.5-4$ \msun\ of material, with $\sim 1.5$ \msun\ below 5000 \kms, and with a kinetic energy of $(4.5-7)\times10^{51}$ erg. The explosion synthesised $\sim 0.14$ \msun\ of 56Ni. There are significant uncertainties in E(B-V)host and the distance however, which will affect Lp and MNi. SN 2016coi exploded in a host similar to the Large Magellanic Cloud (LMC) and away from star-forming regions. The properties of the SN and the host-galaxy suggest that the progenitor had $M_\mathrm{ZAMS}$ of $23-28$ \msun\ and was stripped almost entirely down to its C/O core at explosion.
Comment: Accepted for publication in MNRAS. Updated to reflect the published version, minor typographical changes only
Comment: Accepted for publication in MNRAS. Updated to reflect the published version, minor typographical changes only