The reddening toward cassiopeia A's supernova: Constraining the 56ni yield

Kristoffer A. Eriksen, David Arnett, Donald W. McCarthy, Patrick Young

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


We present new reddening measurements toward the young supernova remnant Cassiopeia A using two techniques not previously applied to this object. Our observations of the near-infrared [FeII] 1.257 μm and 1.644 μm lines show the extinction to be highly variable across the remnant, increasing toward the west and the south, consistent with previous radio and X-ray observations. While the absolute value of AV as determined by the [FeII] lines is uncertain due to conflicting calculations and observations of their intrinsic flux ratio, parts of the remnant without previous optical measurements show comparatively higher reddening. We find AV = 6.2 0.6 from the broadband shape of the infrared synchrotron emission of a knot within 13″ of the expansion center. Given this reddening, the apparent faintness of the nascent supernova, and iron mass constraints from X-ray observations, we estimate an ejected mass of 56Ni of 0.058-0.16 M. Taken with γ-ray observations of the 44Ti decay chain, this nickel mass is broadly consistent with the solar 44Ca/56Fe ratio.

Original languageEnglish (US)
Pages (from-to)29-36
Number of pages8
JournalAstrophysical Journal
Issue number1
StatePublished - 2009


  • Abundances
  • Dust
  • Extinction
  • Nuclear reactions
  • Nucleosynthesis
  • Supernova remnants
  • Supernovae: individual (SN1680)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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