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Title: Uncovering the putative B-star binary companion of the SN 1993J progenitor

The Type IIb supernova (SN) 1993J is one of only a few stripped-envelope SNe with a progenitor star identified in pre-explosion images. SN IIb models typically invoke H envelope stripping by mass transfer in a binary system. For the case of SN 1993J, the models suggest that the companion grew to 22 M{sub ☉} and became a source of ultraviolet (UV) excess. Located in M81, at a distance of only 3.6 Mpc, SN 1993J offers one of the best opportunities to detect the putative companion and test the progenitor model. Previously published near-UV spectra in 2004 showed evidence for absorption lines consistent with a hot (B2 Ia) star, but the field was crowded and dominated by flux from the SN. Here we present Hubble Space Telescope Cosmic Origins Spectrograph and Wide-Field Camera 3 observations of SN 1993J from 2012, at which point the flux from the SN had faded sufficiently to potentially measure the UV continuum properties from the putative companion. The resulting UV spectrum is consistent with contributions from both a hot B star and the SN, although we cannot rule out line-of-sight coincidences.
Authors:
; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA. (United States)
  2. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  3. Caltech, Mailcode 314-6, Pasadena, CA 91125 (United States)
  4. Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden)
  5. National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719-4933 (United States)
  6. National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune University Campus, Ganeshkhind, Pune-411007 (India)
  7. Department of Astronomy and Astrophysics, University of Chicago, 5640 S Ellis Ave, Chicago, IL 60637 (United States)
  8. Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
Publication Date:
OSTI Identifier:
22365621
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 790; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; BINARY STARS; EXPLOSIONS; MASS TRANSFER; SPACE; STRIPPING; SUPERNOVAE; TELESCOPES; ULTRAVIOLET RADIATION; ULTRAVIOLET SPECTRA