The 1972 supernova in NGC 5253. Photometric results from the first observing season.
Abstract
Summary. Photoelectric UBV photometry is presented for the bright 1972 supernova in NGC 5253.48 measurements were made during 16 nights; the period covered is 134 days. The observations provide the normal light and colour curves but make also possible a study of minor fluctuations on a minute as well as on a second time scale. Whereas no fluctuations with a time scale less than one hour are found, we demonstrate the presence of a secondary light and colour variation with a period between 0.1 and 1.0 days. Comparisons of our measurements with published UBV data show very good agreement. The distance modulus of the supernova and the absorption affecting the obtained UBV data are discussed. Two photographic prediscovery-magnitude estimates and two upper-limit estimates of the supernova luminosity give especially high weight to the B light curve. The Zwicky parameters are deducted and discussed. At the luminosity maximum the apparent blue magnitude is B =7.75. Accepting the results of van den Bergh and Sersic for the uncorrected distance modulus this means an absolute blue magnitude of B0 = -20.25. The luminosity maximum in U is found to be 2-4 days before and in Y2-3 days after that in B. Both the light curves and the colour curves are of a type I supernova. The results obtained are compared with those of other supernovae and with theoretical data. Some measures of radiation outburst energy are calculated. The "visual outburst energy" is found to be Evis =7.2 x 10 erg. Galactic absorption data of Shane and Wirtanen are used. Key words. supernova - light curve - decay fluctuation - outburst energy - UBVphotometry
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- October 1973
- Bibcode:
- 1973A&A....28..295A