This paper presents optical photometry and spectroscopy of SN 1987D, a Type Ia supernova in the nearby galaxy UGC 7370, during the period immediately subsequent to its discovery. The distance modulus of the galaxy, independently determined by the redshift and the Tully-Fisher (1977) relation, is 32.3 + or - 1.0. The maximum brightness of SN 1987D was V about 13.2 and occurred on April 18, 1987, + or - 4 days; the absolute luminosity is about 0.6 mag brighter than the average for SNe Ia. The spectrum of SN 1987D is typical of SNe Ia, but the expansion velocity (9600 km/s) is considerably lower than average.
Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 99; 1167-117