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

Filippenko, Alexei V. and Barth, Aaron J. and Matheson, Thomas and Armus, Lee and Brown, Michael J. I. and Espey, Brian R. and Fan, Xiao-Ming and Goodrich, Robert W. and Ho, Luis C. and Junkkarinen, Vesa T. and Koo, David C. and Lehnert, Matthew D. and Martel, André R. and Mazzarella, Joseph M. and Miller, Joseph S. and Smith, Graeme H. and Tytler, David and Wirth, Gregory D. (1995) The Type Ic Supernova 1994I in M51: Detection of Helium and Spectral Evolution. Astrophysical Journal Letters, 450 (1). L11-L15. ISSN 2041-8205. doi:10.1086/309659.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Filippenko, Alexei V.0000-0003-3460-0103
Barth, Aaron J.0000-0002-3026-0562
Matheson, Thomas0000-0001-6685-0479
Armus, Lee0000-0003-3498-2973
Brown, Michael J. I.0000-0002-1207-9137
Ho, Luis C.0000-0001-6947-5846
Lehnert, Matthew D.0000-0003-1939-5885
Mazzarella, Joseph M.0000-0002-8204-8619
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).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Department of Energy (DOE)W-7405-ENG-48
Space Telescope Science InstituteUNSPECIFIED
Subject Keywords:binaries: close; stars: evolution; stars: mass loss; supernovae: general; supernovae: individual (SN 1994I, SN 1987M, SN 1984L)
Issue or Number:1
Record Number:CaltechAUTHORS:20121002-113037407
Persistent URL:
Official Citation:The Type Ic Supernova 1994I in M51: Detection of Helium and Spectral Evolution Alexei V. Filippenko et al. 1995 ApJ 450 L11
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34626
Deposited By: Ruth Sustaita
Deposited On:02 Oct 2012 20:15
Last Modified:09 Nov 2021 23:09

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