Central Bureau for Astronomical Telegrams

IAUC 5741: 1993J

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                                                  Circular No. 5741
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM     EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


SUPERNOVA 1993J IN NGC 3031
     E. Magnier and W. Lewin, Masachusetts Institute of Technology;
L. Lubin, Princeton University; J. van Paradijs, University of
Amsterdam; U. Zimmerman, Max Planck Institute for Extraterrestrial
Physics; and G. Fabbiano, Center for Astrophysics, report: "We
have found an object within 0".25 of the position of SN
1993J on CCD images taken 1992 Jan. 24 at the Michigan-Dartmouth-MIT
Observatory's 2.4-m Hiltner telescope.  The object appears stellar
(FWHM 1".8) but is in a somewhat crowded region.  We find the
following magnitudes and colors: V = 19.7 +/- 0.5, V-R = +0.8 +/- 0.1,
m(H alpha) = 19.54 +/- 0.1, m([S II]) = 19.85 +/- 0.1.
The V magnitude is a quick-look result, and the error should reduce
to < 0.1 mag with careful calibration.  The emission-line fluxes
are from 3.5-nm-wide filter images centered at 655.0 and 673.0 nm,
and magnitudes are calibrated using the standard stars of Oke and
Gunn (1983, Ap.J. 266, 713).  The colors do not appear
to be those of an emission-line object."

     J. Salzer, W. Herbst and G. Vinton, Wesleyan University, report:
"A CCD image taken by Salzer with the 0.9-m telescope at Kitt Peak
on 1992 Oct. 2 includes the field of SN 1993J.  A single R image of
300-s duration was obtained under photometric conditions and shows a faint,
stellar-appearing object with R = 20.0 +/- 0.2 at the supernova's
position.  CCD images obtained with the Van Vleck Observatory's 0.6-m
reflector on 1993 Mar 31.2 UT confirm the identity of the supernova
progenitor to within 0".2.  The nearby star GSC 4383.0340 has R = 14.14
+/- 0.04, and the supernova was at R = 10.7 in the VVO observations.
The observed progenitor brightness is 0.7 mag fainter than the Mar.
1990 measurement reported on IAUC 5736, suggesting significant light
variations in the progenitor--as would be expected in a late-type
supergiant.  A distance modulus of 27.6 gives a luminosity for the
progenitor of M(V) = -6.9, consistent with a K0 Ia."

     G. Calamai, G. Govazzi, I. Randone and G. Tofani report that
near-infrared photometry at the CNR Tirgo Observatory, Gornergrat,
gave J = 10.57 +/- 0.05, H = 10.48 +/- 0.05, K = 10.41 +/- 0.05, in
less than perfect sky conditions during Mar. 31.83-31.93 UT.  Photoelectric
photometry by G. Sostero, A. Lepardo and U. Munari with the Friuli
Astronomical-Meteorological Association's 0.45-m telescope on Mar.
31.972 UT gave V = 11.06, B-V = -0.35 [sic](+/- 0.02, comparison HD
86677).  CCD photometry by P. Prugniel at Haute Provence on Apr. 1.00 UT
gave B = 11.40, B-R = +0.45 (+/- 0.03, Cousins system; cf. IAUC 5736).


1993 April 2                   (5741)              Brian G. Marsden

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