Abstract

Duilia de Mello, Observatorio Nacional, Rio de Janeiro, reports her discovery of a supernova on Jan. 14.15 UT with the European Southern Observatory (ESO) 1.52-m telescope at La Silla; SN 1997D is located 11" east and 43" south of the nucleus of NGC 1536 (R.A. = 4h11m.0, Decl. = -56o29', equinox 2000.0). S. Benetti, ESO, writes: "Inspection of a fully-reduced spectrum (range 369.5- 757.8 nm, resolution about 0.6 nm), obtained on Jan. 14.15 with the ESO 1.52-m telescope (+ Boller & Chivens spectrograph) by the discoverer, confirms SN 1997D to be a peculiar type-II supernova, about 100 days after maximum. The spectrum contains a variety of lines superimposed on a red continuum. H-alpha shows an unusual double-P-Cyg profile, from which expansion velocities of about 5000 and 1200 km/s are derived (the redshift of the galaxy being 1296 km/s). A line with P-Cyg profile (peak measured at 663.3 nm and minimum at 661.5 nm) is visible on the H-alpha red wing. The Na I-D doublet is present with a P-Cyg profile (expansion velocity of about 3700 km/s), together with a strong P- Cyg line of Ba II 614.2-nm (expansion velocity about 2200 km/s) and P-Cyg lines of Sc II at 552.7, 565.8, and 624.5 nm (expansion velocity of about 1800 km/s). Emission lines of Fe II at 492.4, 501.8, and 516.9 nm are present in the supernova spectrum. A relatively strong emission line at 734.3 nm has been identified with the Ca II] 729.1-732.3-nm doublet. H-beta is very weak if present at all." An R image obtained by G. Massone (Osservatorio di Torino) with the 0.9-m Dutch telescope on Jan. 15.05 yields a supernova magnitude of 16.3.