The Type Ib Supernova 1984L in NGC 991
Abstract
We present photometry from ~380 to ~520 days past maximum and spectroscopy at ~400 days past maximum for the type Ib supernova 1984L. The late-time light curve shows an exponential decline with an e-folding time of ~116 days, within the errors, the same as for ^56^Co decay, which powers SN 1987A. If the observed flux arises from the radioactive decay of ^56^Co, the luminosity implies an initial ^56^Ni mass of ~0.1 M_sun_. The late-time spectrum is dominated by [O I] 6300-6363 emission. The required mass of oxygen (~1 M_sun_), the ratios of magnesium to oxygen and magnesium to carbon all seem consistent with the origin of this SN Ib in a star of roughly 20 M_sun_. In addition, we compare SN 1984L to the Type II SN 1980K and SN 1987A, to the type Ib SN 1985F and SN 1987K, and to models. While the SN 1984L data do not exclude the possible origin of SN Ib in C-0 white dwarfs, they demonstrate that direct analysis of supernova photometry and spectra can provide significant clues to the progenitors.
- Publication:
-
The Astronomical Journal
- Pub Date:
- August 1989
- DOI:
- 10.1086/115158
- Bibcode:
- 1989AJ.....98..577S
- Keywords:
-
- Astronomical Photometry;
- Astronomical Spectroscopy;
- Supernovae;
- Cobalt Isotopes;
- Light Curve;
- Luminosity;
- Nickel Isotopes;
- Radioactive Decay;
- Supernova 1987a;
- Visible Spectrum;
- White Dwarf Stars;
- Astronomy;
- STARS: SUPERNOVAE