Observations of supernovae: 1975a in NGC 2207 and 1975b in the Perseus cluster.
Abstract
Spectroscopic, spectrophotometric, and photometric data are discussed which demonstrate that supernova 1975a, located in the NGC 2207/IC 2163 system, was a type I event. January 22.8, 1975, is adopted as the date of maximum light, and an absolute bolometric magnitude of -19.4 at maximum light is estimated. The photospheric radius and temperature five days before maximum light are believed to have been 10 billion km and 12,000 K. The spectroscopic behavior of this supernova is described, emphasizing observed features that agree well with those seen in other type I supernovae and several narrow features that might have arisen in thin shells of absorbing matter. Similar data are discussed for supernova 1975b, which occurred in an anonymous galaxy of the Perseus cluster. The wavelengths are shown to agree very well with those measured for supernova 1975a. The only unusual feature discovered in 1975b was the absence of a clearly defined absorption feature at 6115 A. It is concluded that 1975b was either a normal type I supernova with the 6115-A feature obscured or a peculiar type I event.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1976
- DOI:
- 10.1086/154465
- Bibcode:
- 1976ApJ...207...44K
- Keywords:
-
- Astronomical Spectroscopy;
- Galactic Clusters;
- Image Orthicons;
- Interstellar Extinction;
- Red Shift;
- Supernovae;
- Energy Distribution;
- Milky Way Galaxy;
- Spectrum Analysis;
- Ubv Spectra;
- Astrophysics