The peculiar SN 2005hk: Do some type la supernovae explode as deflagrations?

M. M. Phillips, Weidong Li, Joshua A. Frieman, S. I. Blinnikov, Darren DePoy, José L. Prieto, P. Milne, Carlos Contreras, Gastón Folatelli, Nidia Morrell, Mario Hamuy, Nicholas B. Suntzeff, Miguel Roth, Sergio González, Wojtek Krzeminski, Alexei V. Filippenko, Wendy L. Freedman, Ryan Chornock, Saurabh Jha, Barry F. MadoreS. E. Persson, Christopher R. Burns, Pamela Wyatt, David Murphy, Ryan J. Foley, Mohan Ganeshalingam, Franklin J.D. Serduke, Kevin Krisciunas, Bruce Bassett, Andrew Becker, Ben Dilday, J. Eastman, Peter M. Garnavich, Jon Holtzman, Richard Kessler, Hubert Lampeitl, John Marriner, S. Frank, J. L. Marshall, Gajus Miknaitis, Masao Sako, Donald P. Schneider, Kurt Van Der Heyden, Naoki Yasuda

Research output: Contribution to journalArticlepeer-review


We present extensive u'g'r'i'BVRIYJHK.. photometry and optical spectroscopy of the Type la supernova (SN) 2005hk. These data reveal that SN 2005hk was nearly identical in its observed properties to SN 2002cx, which has been called "the most peculiar known Type la supernova." Both supernovae exhibited highionization SN 1991T-like premaximum spectra, yet low peak luminosities like that of SN 1991bg. The spectra reveal that SN 2005hk, like SN 2002cx, exhibited expansion velocities that were roughly half those of typical Type la supernovae. The R and / light curves of both supernovae were also peculiar in not displaying the secondary maximum observed for normal Type la supernovae. Our YJH photometry of SN 2005hk reveals the same peculiarity in the near-infrared. By combining our optical and near-infrared photometry of SN 2005hk with published ultraviolet light curves obtained with the Swift satellite, we are able to construct a bolometric light curve from ∼15 days before to ∼60 days after Baximum. The shape and unusually low peak luminosity of this light curve, plus the low expansion velocities and absence of a secondary maximum at red and near-infrared wavelengths, are all in reasonable agreement with model calculations of a three-dimensional deflagration that produces ∼0.2 M Ȯ of 56Ni.

Original languageEnglish (US)
Pages (from-to)360-387
Number of pages28
JournalPublications of the Astronomical Society of the Pacific
Issue number854
StatePublished - Apr 2007

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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