@article{a11450e9912f4bc0b2d72ec758473e1a,
title = "SN 2016coi/ASASSN-16fp: An example of residual helium in a type Ic supernova?",
abstract = "The optical observations of Ic-4 supernova (SN) 2016coi/ASASSN-16fp, from \textasciitilde{}2 to \textasciitilde{}450 d 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 \textasciitilde{}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 is 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 \textasciitilde{}16 d after core-collapse reaching a bolometric luminosity of Lp\textasciitilde{}3 × 1042 erg s-1. Spectral models, including the nebular epoch, show that the SN ejected 2.5-4M⊙ of material, with \textasciitilde{}1.5M⊙ below 5000 km s-1, and with a kinetic energy of (4.5-7) × 1051 erg. The explosion synthesized \textasciitilde{}0.14M⊙ of 56Ni. There are significant uncertainties in E(B - V)host and the distance, however, which will affect Lp andMNi. 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 MZAMS of 23-28M⊙ and was stripped almost entirely down to its C/O core at explosion.",
keywords = "SN2016coi/ASASSN16-fp, Supernovae: individual",
author = "Prentice, \{S. J.\} and C. Ashall and Mazzali, \{P. A.\} and Zhang, \{J. J.\} and James, \{P. A.\} and Wang, \{X. F.\} and J. Vink{\'o} and S. Percival and L. Short and A. Piascik and F. Huang and J. Mo and Rui, \{L. M.\} and Wang, \{J. G.\} and Xiang, \{D. F.\} and Xin, \{Y. X.\} and Yi, \{W. M.\} and Yu, \{X. G.\} and Q. Zhai and Zhang, \{T. M.\} and G. Hosseinzadeh and Howell, \{D. A.\} and C. McCully and S. Valenti and B. Cseh and O. Hanyecz and L. Kriskovics and A. P{\'a}l and K. S{\'a}rneczky and A. S{\'o}dor and R. Szak{\'a}ts and P. Sz{\'e}kely and E. Varga-Vereb{\'e}lyi and K. Vida and M. Bradac and Reichart, \{D. E.\} and D. Sand and L. Tartaglia",
note = "Funding Information: SJP and CA are funded by a Science and Technology Facilities Council (STFC) grant. CA acknowledges the support provided by the National Science Foundation (NSF) under Grant No. AST-1613472. The LT is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the STFC. This paper makes use of data from Las Cumbres Observatory and the Supernova Key Project. DAH, CM, and GH are supported by NSF grant number 1313484. Research by DJS and L.T. is supported by NSF grant AST-1412504 and AST-1517649. Research at Lick Observatory is partially supported by a generous gift from Google. Funding for the Lijiang 2.4 m telescope (LJT) has been provided by the Chinese Academy of Sciences (CAS) and the People{\textquoteright}s Government of Yunnan Province. The LJT is jointly operated and administrated by Yunnan Observatories and Center for Astronomical Mega-Science (CAS). J.-J. Zhang is supported by National Science Foundation of China (NSFC, grants 11403096 and 11773067), the Youth Innovation Promotion Association of the CAS, the Western Light Youth Project, and the Key Research Program of the CAS (grant no. KJZD-EW-M06). Finally, we thank the anonymous referee for their time, consideration, and patience. Funding Information: SJP and CA are funded by a Science and Technology Facilities Council (STFC) grant. CA acknowledges the support provided by the National Science Foundation (NSF) under Grant No. AST-1613472. The LT is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de losMuchachos of the Instituto de Astrofisica de Canarias with financial support from the STFC. This paper makes use of data from Las Cumbres Observatory and the Supernova Key Project. DAH, CM, and GH are supported by NSF grant number 1313484. Research by DJS and L.T. is supported by NSF grant AST-1412504 and AST-1517649. Research at Lick Observatory is partially supported by a generous gift from Google. Funding for the Lijiang 2.4 m telescope (LJT) has been provided by the Chinese Academy of Sciences (CAS) and the People's Government of Yunnan Province. The LJT is jointly operated and administrated by Yunnan Observatories and Center for Astronomical Mega-Science (CAS). J.-J. Zhang is supported by National Science Foundation of China (NSFC, grants 11403096 and 11773067), the Youth Innovation Promotion Association of the CAS, the Western Light Youth Project, and the Key Research Program of the CAS (grant no. KJZD-EW-M06). Finally, we thank the anonymous referee for their time, consideration, and patience. Publisher Copyright: {\textcopyright} 2018 The Author(s).",
year = "2018",
month = aug,
day = "1",
doi = "10.1093/MNRAS/STY1223",
language = "English (US)",
volume = "478",
pages = "4162--4192",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "3",
}