Central Bureau for Astronomical Telegrams

IAUC 5769: 1993J; N Oph 1993

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                                                  Circular No. 5769
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
     R. Tweedy, Steward Observatory; T. Balonek, Colgate University;
and L. Wells, National Optical Astronomy Observatory and Kitt Peak
National Observatory, report:  "Several consecutive nights of UBVRI
CCD photometry with the Burrell Schmidt telescope at Kitt Peak (cf.
IAUC 5746, 5754) indicate that the brightness in U is no longer
increasing. This indicates the probable onset of the plateau phase
in the light curve.  The rate of brightening is decreasing at other
colors as well.  Magnitudes on Apr. 16.15 UT (using Corwin's
reference stars, IAUC 5742, uncorrected for color) are U = 11.35, B =
11.40, V = 10.88, R = 10.55, I = 10.46 (errors +/- 0.01-0.02), with
the present rates of increase being 0.00, 0.03, 0.04, 0.05, 0.05
mag/day, respectively."
     Further photoelectric photometry (cf. IAUC 5750, 5755, 5758)
by P. N. Appleton and J. J. Eitter, Iowa State University (AE;
observations made with the E. W. Fick 0.6-m wide-field CCD system;
magnitudes referred to Corwin's stars 0434 and 0928 from IAUC 5742;
rms error typically 0.03 mag); by M. Mikolajewski, K. Ruminski, and
B. Wikierski, N. Copernicus University, Torun (M); and by P.
Prugniel, Observatoire de Haute Provence (P):  Apr. 4.1 UT, V =
11.81, B-V = +0.45, V-R = +0.31, V-I = +0.57 (AE); 5.1, V = 11.96,
B-V = +0.34, V-R = +0.45, V-I = +0.66 (AE); 6.1, V = 11.86, V-R =
+0.41 (AE); 10.1, V = 11.37, B-V = +0.50, V-R = +0.33, V-I = +0.44
(AE); 13.1, V = 11.07, B-V = +0.51, V-R = +0.32, V-I = +0.43 (AE);
15.87, V = 10.87 +/- 0.02, U-B = -0.01, B-V = +0.54, V-R = +0.51,
V-I = +0.40 (M); 16.89, V = 10.86 +/- 0.01, U-B = -0.11, B-V =
+0.57, V-R = +0.49, V-I = +0.42 (M); 17.07, V = 10.86 +/- 0.02, U-B
= -0.19, B-V = +0.56, V-R = +0.44, V-I = +0.41 (M); 17.1, V = 10.85,
B-V = +0.56, V-I = +0.44 (AE); 18.00, Bc = 11.64, Bc-Rc = +0.93 (P);
19.00, Bc = 11.69, Bc-Rc = +1.02 (P); 19.88, V = 10.87 +/- 0.01,
U-B = -0.02, B-V = +0.68, V-R = +0.57, V-I = +0.57 (M); 20.00, Bc =
11.74, Bc-Rc = +1.05 (P).


NOVA OPHIUCHI 1993
     K. Sekiguchi, South African Astronomical Observatory, forwards
the following provisional photometry of N Oph 1993 obtained on Apr.
19.06 UT by F. van Wyk with the 0.5-m reflector at SAAO Sutherland:
V = 9.71, B-V = +0.89, U-B = -0.30, V-Rc = +0.92, V-Ic = +1.70.


1993 April 20                  (5769)            Daniel W. E. Green

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