Published September 1, 1995 | Version Published
Journal Article Open

The Type Ic Supernova 1994I in M51: Detection of Helium and Spectral Evolution

  • 1. ROR icon University of California, Berkeley
  • 2. ROR icon University of Arizona
  • 3. ROR icon Johns Hopkins University
  • 4. ROR icon University of California, San Diego
  • 5. ROR icon Columbia University
  • 6. ROR icon University of California, Santa Cruz
  • 7. ROR icon Space Telescope Science Institute
  • 8. ROR icon Lawrence Livermore National Laboratory
  • 9. ROR icon Infrared Processing and Analysis Center

Abstract

We present a series of spectra of SN 1994I in M51, starting 1 week prior to maximum brightness. The nebular phase began about 2 months after the explosion; together with the rapid decline of the optical light, this suggests that the ejected mass was small. Although lines of He I in the optical region are weak or absent, consistent with the Type Ic classification, we detect strong He I λ10830 absorption during the first month past maximum. Thus, if SN 1994I is a typical Type Ic supernova, the atmospheres of these objects cannot be completely devoid of helium. The emission-line widths are smaller than predicted by the model of Nomoto and coworkers, in which the iron core of a low-mass carbon-oxygen star collapses. They are, however, larger than in Type Ib supernovae.

Additional Information

© 1995 American Astronomical Society. Received 1995 May 19; accepted 1995 June 14. This work was supported by grants from NSF, most recently AST-9417213; from NASA, especially GO-2563.01-87A from STScI (operated by AURA, Inc., under NASA contract NAS5-26555); and from the DOE (contract W-7405-ENG-48). We thank the Lick staff for their assistance, and R. P. Harkness for the digital spectrum of SN 1984L (Fig. 2).

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Identifiers

Eprint ID
34626
Resolver ID
CaltechAUTHORS:20121002-113037407

Funding

NSF
AST-9417213
NASA
GO-2563.01-87A
NASA
NAS5-26555
Department of Energy (DOE)
W-7405-ENG-48
Space Telescope Science Institute

Dates

Created
2012-10-02
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Updated
2021-11-09
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