### Abstract

We revisit the evidence for the contribution of the long-lived radioactive nuclides ^{44}Ti, ^{55}Fe, ^{56}Co, ^{57}Co, and ^{60}Co 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 ^{44}Ti, ^{55}Co, ^{56}Ni, ^{57}Ni, and ^{60}Co, we perform a least squares fit to the constructed composite bolometric light curve. For the nickel isotopes, we obtain best fit values of M(^{56}Ni) = (7.1 ± 0.3) × 10 ^{-2} M _{⊙} and M(^{57}Ni) = (4.1 ± 1.8) × 10^{-3} M _{⊙}. Our best fit ^{44}Ti mass is M(^{44}Ti) = (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 ^{55}Co and ^{60}Co and, as a result, we only give upper limits on the production masses of M(^{55}Co) < 7.2 × 10^{-3} M _{⊙} and M(^{60}Co) < 1.7 × 10^{-4} M _{⊙}. Furthermore, we find that the leptonic channels in the decay of ^{57}Co (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 [^{57}Ni/^{56}Ni] = 2.5 ± 1.1, which is still somewhat high but is in agreement with gamma-ray observations and model predictions.

Original language | English (US) |
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Article number | 10 |

Journal | Astrophysical Journal |

Volume | 792 |

Issue number | 1 |

DOIs | |

State | Published - Sep 1 2014 |

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### Keywords

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

### ASJC Scopus subject areas

- Space and Planetary Science
- Astronomy and Astrophysics

### Cite this

*Astrophysical Journal*,

*792*(1), [10]. https://doi.org/10.1088/0004-637X/792/1/10

**The light curve of SN 1987A revisited : Constraining production masses of radioactive nuclides.** / Seitenzahl, Ivo R.; Timmes, Francis; Magkotsios, Georgios.

Research output: Contribution to journal › Article

*Astrophysical Journal*, vol. 792, no. 1, 10. https://doi.org/10.1088/0004-637X/792/1/10

}

TY - JOUR

T1 - The light curve of SN 1987A revisited

T2 - Constraining production masses of radioactive nuclides

AU - Seitenzahl, Ivo R.

AU - Timmes, Francis

AU - Magkotsios, Georgios

PY - 2014/9/1

Y1 - 2014/9/1

N2 - 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.

AB - 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.

KW - nuclear reactions, nucleosynthesis, abundances

KW - supernovae: general

KW - supernovae: individual (SN 1987A)

UR - http://www.scopus.com/inward/record.url?scp=84906243671&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84906243671&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/792/1/10

DO - 10.1088/0004-637X/792/1/10

M3 - Article

AN - SCOPUS:84906243671

VL - 792

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 10

ER -