Late time optical spectra from the /sup 56/Ni model for Type I supernovae

Technical Report · Tue Jul 01 04:00:00 EDT 1980

DOI:https://doi.org/10.2172/7096402· OSTI ID:7096402

Axelrod, T S

The hypothesis that the optical luminosity of Type I supernovae results from the radioactive decay of /sup 56/Ni synthesized and ejected by the explosion has been investigated by numerical simulation of the optical spectrum resulting from a homologously expanding shell composed initially of pure /sup 56/Ni core. This model, which neglects the effects of material external to the /sup 56/Ni core, is expected to provide a reasonable representation of the supernova at late times when the star is nearly transparent to optical photons. The numerical simulation determines the temperature, ionization state, and non-LTE level populations which result from energy deposition by the radioactive decay products of /sup 56/Ni and /sup 56/Co. The optical spectrum includes the effects of both allowed and forbidden lines. The optical spectra resulting from the simulation are found to be sensitive to the mass and ejection velocity of the /sup 56/Ni shell. A range of these parameters has been found which results in good agreement with the observed spectra of SN1972e over a considerable range of time. In particular, evidence for the expected decaying abundance of /sup 56/Co has been found in the spectra of SN1972e. These results are used to assess the validity of the /sup 56/Ni model and set limits on the mass and explosion mechanism of the Type I progenitor. The possibilities for improvement of the numerical model are discussed and future atomic data requirements defined.

• Research Organization: California Univ., Livermore (USA). Lawrence Livermore Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7096402
• Report Number(s): UCRL-52994
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CHEMICAL COMPOSITION
COBALT 56
COBALT ISOTOPES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
EMISSION SPECTRA
ERUPTIVE VARIABLE STARS
EVEN-EVEN NUCLEI
INTERMEDIATE MASS NUCLEI
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LUMINOSITY
MATHEMATICAL MODELS
NICKEL 56
NICKEL ISOTOPES
NUCLEI
ODD-ODD NUCLEI
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIOISOTOPES
SIMULATION
SPECTRA
STAR MODELS
STARS
SUPERNOVAE
VARIABLE STARS
VISIBLE SPECTRA