SN 2017ivv: two years of evolution of a transitional Type II supernova

Gutiérrez, CP, Pastorello, A, Jerkstrand, A, Galbany, L, Sullivan, M, Anderson, JP, Taubenberger, S, Kuncarayakti, H, González-Gaitán, S, Wiseman, P, Inserra, C, Fraser, M, Maguire, K, Smartt, S, Müller-Bravo, TE, Arcavi, I, Benetti, S, Bersier, D, Bose, S, Bostroem, KA et al (2020) SN 2017ivv: two years of evolution of a transitional Type II supernova. Monthly Notices of the Royal Astronomical Society, 499 (1). pp. 974-992. ISSN 0035-8711

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Abstract

We present the photometric and spectroscopic evolution of the Type II supernova (SN II) SN 2017ivv (also known as ASASSN-17qp). Located in an extremely faint galaxy (M$_r=-10.3$ mag), SN 2017ivv shows an unprecedented evolution during the two years of observations. At early times, the light curve shows a fast rise ($\sim6-8$ days) to a peak of ${\rm M}^{\rm max}_{g}= -17.84$ mag, followed by a very rapid decline of $7.94\pm0.48$ mag per 100 days in the $V-$band. The extensive photometric coverage at late phases shows that the radioactive tail has two slopes, one steeper than that expected from the decay of $^{56}$Co (between 100 and 350 days), and another slower (after 450 days), probably produced by an additional energy source. From the bolometric light curve, we estimated that the amount of ejected $^{56}$Ni is $\sim0.059\pm0.003$ M$\odot$. The nebular spectra of SN 2017ivv show a remarkable transformation that allows the evolution to be split into three phases: (1) H$\alpha$ strong phase ($<200$ days); (2) H$\alpha$ weak phase (between 200 and 350 days); and (3) H$\alpha$ broad phase ($>500$ days). We find that the nebular analysis favours a binary progenitor and an asymmetric explosion. Finally, comparing the nebular spectra of SN 2017ivv to models suggests a progenitor with a zero-age main-sequence mass of 15 -- 17 \Msun.

Item Type:	Article
Additional Information:	This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2020 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords:	0201 Astronomical and Space Sciences
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	Oxford University Press
Related URLs:	http://arxiv.org/abs/2008.09628v1
Date of acceptance:	3 September 2020
Date of first compliant Open Access:	1 April 2021
Date Deposited:	01 Apr 2021 12:40
Last Modified:	04 Sep 2021 05:39
DOI or ID number:	10.1093/mnras/staa2763
URI:	https://ljmu-9.eprints-hosting.org/id/eprint/14736

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