Optical spectroscopy of the somewhat peculiar type IIb supernova 2001ig

Jeffrey M. Silverman, Paolo Mazzali, Ryan Chornock, Alexei V. Filippenko, Alejandro Clocchiatti, Mark M. Phillips, Mohan Ganeshalingam, Ryan J. Foley

Research output: Contribution to journalArticlepeer-review


Here we present previously unpublished optical spectra of supernova (SN) 2001ig, a Type IIb SN, from about a week after explosion until nearly one year later. The earliest spectrum consists of only a few broad absorption features, but soon more common Type II SN features including hydrogen P Cygni profiles and helium absorption become apparent. At later times, as the H features fade and the He I absorption becomes more prominent, we observe the SN to transition from a Type II to a Type Ib. Finally, observations after 250 days past explosion show a nebular-phase SN spectrum with one of the largest magnesium to oxygen intensity ratios ever seen. Additionally, we present models of the late-time spectra which indicate that the inner ejecta consist of ∼1:15 M⊙ of material, most of which (by mass) is in the form of oxygen, with ∼0:13 M⊙ of 56Ni and essentially no hydrogen.

Original languageEnglish (US)
Pages (from-to)689-698
Number of pages10
JournalPublications of the Astronomical Society of the Pacific
Issue number881
StatePublished - Jul 2009

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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