SN 2017ens: The Metamorphosis of a Luminous Broadlined Type Ic Supernova into an SN IIn
Date Issued
2018
Author(s)
Chen, T. -W.
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Inserra, C.
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Fraser, M.
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Moriya, T. J.
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Schady, P.
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Schweyer, T.
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Filippenko, A. V.
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Perley, D. A.
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Ruiter, A. J.
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Seitenzahl, I.
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Sollerman, J.
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Taddia, F.
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Anderson, J. P.
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Foley, R. J.
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Jerkstrand, A.
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Ngeow, C. -C.
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Pan, Y. -C.
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•
Points, S.
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Smartt, S. J.
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Smith, K. W.
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Taubenberger, S.
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Wiseman, P.
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Young, D. R.
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Berton, M.
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Clark, P.
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•
Galbany, L.
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Gal-Yam, A.
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Gromadzki, M.
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Gutiérrez, C. P.
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Heinze, A.
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Kankare, E.
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Kilpatrick, C. D.
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Kuncarayakti, H.
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Leloudas, G.
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Lin, Z. -Y.
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Maguire, K.
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Mazzali, P.
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McBrien, O.
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Prentice, S. J.
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Rau, A.
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Rest, A.
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Siebert, M. R.
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Stalder, B.
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Tonry, J. L.
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Yu, P. -C.
Abstract
We present observations of supernova (SN) 2017ens, discovered by the ATLAS survey and identified as a hot blue object through the GREAT program. The redshift z = 0.1086 implies a peak brightness of M g = -21.1 mag, placing the object within the regime of superluminous supernovae. We observe a dramatic spectral evolution, from initially being blue and featureless, to later developing features similar to those of the broadlined Type Ic SN 1998bw, and finally showing ∼2000 km s-1 wide Hα and Hβ emission. Relatively narrow Balmer emission (reminiscent of a SN IIn) is present at all times. We also detect coronal lines, indicative of a dense circumstellar medium. We constrain the progenitor wind velocity to ∼50-60 km s-1 based on P-Cygni profiles, which is far slower than those present in Wolf-Rayet stars. This may suggest that the progenitor passed through a luminous blue variable phase, or that the wind is instead from a binary companion red supergiant star. At late times we see the ∼2000 km s-1 wide Hα emission persisting at high luminosity (∼3 × 1040 erg s-1) for at least 100 day, perhaps indicative of additional mass loss at high velocities that could have been ejected by a pulsational pair instability.
Volume
867
Issue
2
Start page
L31
Issn Identifier
2041-8205
Ads BibCode
2018ApJ...867L..31C
Rights
open.access
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