Supernova 1996ai in NGC 5005

Claudio Bottari, Sava, Italy, reports his discovery on a CCD image (+ ISIS deep-sky filter) obtained on June 16.86 UT of a supernova of mag 14.5 located some 50" east-northeast of the center of NGC 5005. S. Nakano, Sumoto, Japan, relays a subsequent unfiltered CCD observation by R. and Y. Kushida (Yatsugatake South Base Observatory) on June 19.472, which confirms the presence of a new star of mag 13.0 (near an apparent H II clump) that was not present on a May 12 image (limiting mag 16.5), located at R.A. = 13h10m58s.13, Decl. = +37o03'35".4 (equinox 2000.0). P. Garnavich, P. Challis, and R. Kirshner, Center for Astrophysics, communicate: "Spectra obtained by P. Challis with the Multiple Mirror Telescope and by P. Berlind with the 1.5-m Tillinghast telescope on June 20.3 UT show a red continuum with a strong, broad absorption feature at 614.81 nm. The spectra suggest that SN 1996ai is an extremely obscured type-Ia supernova, a few days before maximum light. A deep Na I interstellar absorption line is observed at 591.4 nm with an equivalent width of 0.23 nm. The steep red continuum implies E(B-V) > 1.0 when compared with SN 1996X at a similar phase. CCD images taken with the Whipple Observatory 1.2-m telescope by J. Kleyna on June 20.3 show the supernova 24" east and 4" north of the galaxy nucleus at V = 16.2 +/- 0.2."