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Numerically Modeling the First Peak of the Type IIb SN 2016gkg

Piro, Anthony L. and Muhleisen, Marc and Arcavi, Iair and Sand, David J. and Tartaglia, Leonardo and Valenti, Stefano (2017) Numerically Modeling the First Peak of the Type IIb SN 2016gkg. Astrophysical Journal, 846 (2). Art. No. 94. ISSN 1538-4357.

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Many Type IIb supernovae (SNe) show a prominent additional early peak in their light curves, which is generally thought to be due to the shock cooling of extended hydrogen-rich material surrounding the helium core of the exploding star. The recent SN 2016gkg was a nearby Type IIb SN discovered shortly after explosion, which makes it an excellent candidate for studying this first peak. We numerically explode a large grid of extended envelope models and compare these to SN 2016gkg to investigate what constraints can be derived from its light curve. This includes exploring density profiles for both a convective envelope and an optically thick steady-state wind, the latter of which has not typically been considered for Type IIb SNe models. We find that roughly ~ 0.02 M⊙ of extended material with a radius of ≈ 180-260 R⊙ reproduces the photometric light curve data, consistent with pre-explosion imaging. These values are independent of the assumed density profile of this material, although a convective profile provides a somewhat better fit. We infer from our modeling that the explosion must have occurred within ≈2–3 hr of the first observed data point, demonstrating that this event was caught very close to the moment of explosion. Nevertheless, our best-fitting 1D models overpredict the earliest velocity measurements, which suggests that the hydrogen-rich material is not distributed in a spherically symmetric manner. We compare this to the asymmetries that have also been seen in the SN IIb remnant Cas A, and we discuss the implications of this for Type IIb SN progenitors and explosion models.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Piro, Anthony L.0000-0001-6806-0673
Arcavi, Iair0000-0001-7090-4898
Sand, David J.0000-0003-4102-380X
Tartaglia, Leonardo0000-0003-3433-1492
Valenti, Stefano0000-0001-8818-0795
Additional Information:© 2017 The American Astronomical Society. Received 2017 March 2; revised 2017 July 31; accepted 2017 August 8; published 2017 September 5. We thank Maria Drout, Chris Kochanek, and Ben Shappee for feedback on a previous draft, and Saurabh Jha for helpful discussions. We thank the Summer Undergraduate Research Fellowship (SURF) program at Caltech, which supported the internship of M.E.M. at the Carnegie Observatories. We also thank Drew Clausen for generating the 15 M⊙ model and associated helium core with MESA that was used in this work. Support for I.A. was provided by NASA through the Einstein Fellowship Program, grant PF6-170148. D.J.S. acknowledges support from NSF grant AST-1517649. The computations were performed on the MIES cluster of the Carnegie Observatories, which was made possible by a grant from the Ahmanson Foundation.
Funding AgencyGrant Number
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
NASA Einstein FellowshipPF6-170148
Ahmanson FoundationUNSPECIFIED
Subject Keywords:hydrodynamics – radiative transfer – supernovae: general – supernovae: individual (SN 2016gkg)
Issue or Number:2
Record Number:CaltechAUTHORS:20170905-154604575
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Official Citation:Anthony L. Piro et al 2017 ApJ 846 94
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:81163
Deposited By: Tony Diaz
Deposited On:05 Sep 2017 22:56
Last Modified:09 Mar 2020 13:19

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