SN 2017ens: The Metamorphosis of a Luminous Broadlined Type Ic Supernova into an SN IIn

DOI: 
10.3847/2041-8213/aaeb2e
Publication date: 
28/11/2018
Main author: 
Chen T.-W.
IAA authors: 
Valle, M.D.
Authors: 
Chen T.-W., Inserra C., Fraser M., Moriya T.J., Schady P., Schweyer T., Filippenko A.V., Perley D.A., Ruiter A.J., Seitenzahl I., Sollerman J., Taddia F., Anderson J.P., Foley R.J., Jerkstrand A., Ngeow C.-C., Pan Y.-C., Pastorello A., Points S., Smartt S.J., Smith K.W., Taubenberger S., Wiseman P., Young D.R., Benetti S., Berton M., Bufano F., Clark P., Valle M.D., Galbany L., Gal-Yam A., Gromadzki M., Gutiérrez C.P., Heinze A., Kankare E., Kilpatrick C.D., Kuncarayakti H., Leloudas G., Lin Z.-Y., Maguire K., Mazzali P., McBrien O., Prentice S.J., Rau A., Rest A., Siebert M.R., Stalder B., Tonry J.L., Yu P.-C.
Journal: 
Astrophysical Journal Letters
Refereed: 
Yes
Publication type: 
Article
Volume: 
867
Pages: 
L31
Number: 
L31
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. © 2018. The American Astronomical Society. All rights reserved.
Database: 
SCOPUS
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2018ApJ...867L..31C/abstract
ADS Bibcode: 
2018ApJ...867L..31C
Keywords: 
supernovae: general; supernovae: individual (SN 2017ens)