The nature of SN 1997D: low-mass progenitor and weak explosion
Abstract
We analyzed the spectra and light curve of the peculiar type II-P supernova 1997D to recover ejecta parameters. The optimal hydrodynamical model of SN 1997D, which meets observational constraints at the photospheric epoch, suggests a low explosion energy of about 1050 erg, ejecta mass around 6 Msun, and presupernova radius near 85 Rsun. We confirm the previous result by Turatto et al. (\cite{tmy98}) that the ejecta contain a very low amount of radioactive 56Ni (~ 0.002 Msun). Modelling the nebular spectrum supports the hydrodynamical model and permits us to estimate the mass of freshly synthesized oxygen (0.02-0.07 Msun). Combined with the basic results of stellar evolution theory the obtained parameters of SN 1997D imply that the progenitor was a star from the 8-12 Msun mass range at the main sequence. The fact that at least some progenitors from this mass range give rise to core-collapse supernovae with a low kinetic energy (~ 1050 erg) and low amount of radioactive 56Ni (~ 0.002 Msun) has no precedent and imposes important constraints on the explosion mechanism. We speculate that the galactic supernovae 1054 and 1181 could be attributed to SN 1997D-like events. All the SN~1997D spectra used in this paper were kindly provided by Massimo Turrato
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 2000
- DOI:
- 10.48550/arXiv.astro-ph/9906190
- arXiv:
- arXiv:astro-ph/9906190
- Bibcode:
- 2000A&A...354..557C
- Keywords:
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- SUPERNOVAE: GENERAL;
- SUPERNOVAE: INDIVIDUAL: SN 1997D;
- ISM: SUPERNOVA REMNANTS;
- Astrophysics
- E-Print:
- 11 pages, 11 figures, submitted to A&