We present observational data for a peculiar supernova discovered by the OGLE-IV survey and followed by the Public ESO Spectroscopic Survey for Transient Objects. The inferred redshift of z=0.07 implies an absolute magnitude in the rest-frame I-band of MI∼−17.6 mag. This places it in the luminosity range between normal Type Ia SNe and novae. Optical and near infrared spectroscopy reveal mostly Ti and Ca lines, and an unusually red color arising from strong depression of flux at rest wavelengths <5000 \AA. To date, this is the only reported SN showing Ti-dominated spectra. The data are broadly consistent with existing models for the pure detonation of a helium shell around a low-mass CO white dwarf and "double-detonation" models that include a secondary detonation of a CO core following a primary detonation in an overlying helium shell.
@article{arxiv.1410.6473,
title = {OGLE-2013-SN-079: a lonely supernova consistent with a helium shell detonation},
author = {C. Inserra and S. A. Sim and L. Wyrzykowski and S. J. Smartt and M. Fraser and M. Nicholl and K. J. Shen and A. Jerkstrand and A. Gal-Yam and D. A. Howell and K. Maguire and P. Mazzali and S. Valenti and S. Taubenberger and S. Benitez-Herrera and D. Bersier and N. Blagorodnova and H. Campbell and T. -W. Chen and N. Elias-Rosa and W. Hillebrandt and Z. Kostrzewa-Rutkowska and S. Kozlowski and M. Kromer and J. D. Lyman and J. Polshaw and F. K. Ropke and A. J. Ruiter and K. Smith and S. Spiro and M. Sullivan and O. Yaron and D. Young and F. Yuan},
journal= {arXiv preprint arXiv:1410.6473},
year = {2015}
}
Comments
ApJ Letter accepted on the 5th of December 2014. 8 pages, 3 figures. This version matches the upcoming published one