The light curve of SN 1987A revisited: Constraining production masses of radioactive nuclides

Ivo R. Seitenzahl, Francis Timmes, Georgios Magkotsios

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

We revisit the evidence for the contribution of the long-lived radioactive nuclides 44Ti, 55Fe, 56Co, 57Co, and 60Co to the UVOIR light curve of SN 1987A. We show that the V-band luminosity constitutes a roughly constant fraction of the bolometric luminosity between 900 and 1900 days, and we obtain an approximate bolometric light curve out to 4334 days by scaling the late time V-band data by a constant factor where no bolometric light curve data is available. Considering the five most relevant decay chains starting at 44Ti, 55Co, 56Ni, 57Ni, and 60Co, we perform a least squares fit to the constructed composite bolometric light curve. For the nickel isotopes, we obtain best fit values of M(56Ni) = (7.1 ± 0.3) × 10 -2 M and M(57Ni) = (4.1 ± 1.8) × 10-3 M . Our best fit 44Ti mass is M(44Ti) = (0.55 ± 0.17) × 10-4 M , which is in disagreement with the much higher (3.1 ± 0.8) × 10-4 M recently derived from INTEGRAL observations. The associated uncertainties far exceed the best fit values for 55Co and 60Co and, as a result, we only give upper limits on the production masses of M(55Co) < 7.2 × 10-3 M and M(60Co) < 1.7 × 10-4 M . Furthermore, we find that the leptonic channels in the decay of 57Co (internal conversion and Auger electrons) are a significant contribution and constitute up to 15.5% of the total luminosity. Consideration of the kinetic energy of these electrons is essential in lowering our best fit nickel isotope production ratio to [57Ni/56Ni] = 2.5 ± 1.1, which is still somewhat high but is in agreement with gamma-ray observations and model predictions.

Original languageEnglish (US)
Article number10
JournalAstrophysical Journal
Volume792
Issue number1
DOIs
StatePublished - Sep 1 2014

Keywords

  • nuclear reactions, nucleosynthesis, abundances
  • supernovae: general
  • supernovae: individual (SN 1987A)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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