PTF11iqb: Cool supergiant mass-loss that bridges the gap between Type IIn and normal supernovae

Nathan Smith*, Jon C. Mauerhan, S. Bradley Cenko, Mansi M. Kasliwal, Jeffrey M. Silverman, Alexei V. Filippenko, Avishay Gal-Yam, Kelsey I. Clubb, Melissa L. Graham, Douglas C. Leonard, J. Chuck Horst, G. Grant Williams, Jennifer E. Andrews, Shrinivas R. Kulkarni, Peter Nugent, Mark Sullivan, Kate Maguire, Dong Xu, Sagi Ben-Ami

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

113 Citations (Scopus)

Abstract

The supernova (SN) PTF11iqb was initially classified as a Type IIn event caught very early after explosion. It showed narrowWolf-Rayet (WR) spectral features on day 2 (as in SN 1998S and SN 2013cu), but the narrow emission weakened quickly and the spectrum morphed to resemble Types II-L and II-P. At late times, H alpha exhibited a complex, multipeaked profile reminiscent of SN 1998S. In terms of spectroscopic evolution, we find that PTF11iqb was a near twin of SN 1998S, although with somewhat weaker interaction with circumstellar material (CSM) at early times, and stronger interaction at late times. We interpret the spectral changes as caused by early interaction with asymmetric CSM that is quickly (by day 20) enveloped by the expanding SN ejecta photosphere, but then revealed again after the end of the plateau when the photosphere recedes. The light curve can be matched with a simple model for CSM interaction (with a mass-loss rate of roughly 10(-4) M-circle dot yr(-1)) added to the light curve of a normal SN II-P. The underlying plateau requires a progenitor with an extended hydrogen envelope like a red supergiant at the moment of explosion, consistent with the slow wind speed (<80 km s−1) inferred from narrow Hα emission. The cool supergiant progenitor is significant because PTF11iqb showed WR features in its early spectrum – meaning that the presence of such WR features does not necessarily indicate a WR-like progenitor. Overall, PTF11iqb bridges SNe IIn with weaker pre-SN mass-loss seen in SNe II-L and II-P, implying a continuum between these types.
Original languageEnglish
Pages (from-to)1876-1896
Number of pages21
JournalMonthly notices of the Royal Astronomical Society
Volume449
Issue number2
Early online date26 Mar 2015
DOIs
Publication statusPublished - 11 May 2015

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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