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 [superscript 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 [57Ni/56Ni] = 2.5 ± 1.1, which is still somewhat high but is in agreement with gamma-ray observations and model predictions.
Details
- The Light Curve of SN 1987A Revisited: Constraining Production Masses of Radioactive Nuclides
- Seitenzahl, Ivo R. (Author)
- Timmes, Francis (Author)
- Magkotsios, Georgios (Author)
- College of Liberal Arts and Sciences (Contributor)
-
Digital object identifier: 10.1088/0004-637X/792/1/10
-
Identifier TypeInternational standard serial numberIdentifier Value0004-637X
-
Identifier TypeInternational standard serial numberIdentifier Value1538-4357
-
Copyright IOP Publishing. This is the authors' final, peer-reviewed manuscript. The final version as published can be viewed online at http://dx.doi.org/10.1088/0004-637X/792/1/10
Citation and reuse
Cite this item
This is a suggested citation. Consult the appropriate style guide for specific citation guidelines.
Seitenzahl, Ivo R., Timmes, F. X., & Magkotsios, Georgios (2014). THE LIGHT CURVE OF SN 1987A REVISITED: CONSTRAINING PRODUCTION MASSES OF RADIOACTIVE NUCLIDES. ASTROPHYSICAL JOURNAL, 792(1), 10. http://dx.doi.org/10.1088/0004-637X/792/1/10