Supernova 1988A in M58 (original) (raw)

Abstract

H. Kosai, Tokyo Astronomical Observatory, reported the visual discovery on Jan. 18 by Kaoru Ikeya, Maisaka-machi, Shizuoka, of a possible supernova in M58 (NGC 4579; R.A. = 12h35.1, Decl. = +12 05', equinox 1950.0), located 40" due south of the galaxy's center. An independent discovery was made by Robert O. Evans, Hazelbrook, N.S.W. The following visual magnitude estimates are available: Jan. 15.7 UT, [15.5 (Evans); 18.799, 13.5 (Ikeya); 20.757, 13.5 (Ikeya); 22.45, 13.9 (J. Bryan, Georgetown, TX); 22.73, 14.5 (Evans). J. C. Wheeler, University of Texas at Austin, reports an observation obtained Jan. 22 at McDonald Observatory by A. Cochran and E. Barker under unfavorable weather conditions, revealing a supernova-like object with a fairly featureless spectrum and a broad emission feature near H-beta, with a deep absorption on the blueward side of the emission. E. M. Schlegel, Center for Astrophysics, reports that a low signal-to-noise, low-dispersion (400-700 nm) spectrum, obtained by J. Peters on Jan. 22.5 with the 1.5-m telescope (+ Z-machine) at Whipple Observatory (poor seeing), indicates this to be probably a type-II SN, not long after maximum; the FWZI of the H-alpha emission is at least 10 000 km/s and may show a weak P-Cyg profile.