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IAUC 5770: 1993J

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                                                  Circular No. 5770
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
     V. Klochkova and V. Panchuk, Special Astrophysical Observatory,
report:  "Four CCD spectrograms (range 400-1000 nm; resolution
about 0.15-0.2 nm, S/N > 100) of SN 1993J were obtained on Apr. 5/6
at the 6-m telescope (+ medium-resolution echelle spectrometer,
Zebra).  The Balmer and Pashen series of hydrogen are absent in
these spectra.  The only spectral details revealed were the
interstellar Na I 588.9- and 589.5-nm lines, each of these doublet
components being split; we estimated the radial velocities for the
components as -103, -2, and +128 km/s."
     P. Prugniel, Observatoire de Haute Provence, writes: "To match
the 'zero point' of Corwin's photometry for star 0928 (IAUC 5742),
corrections of -0.11 in Bc and +0.04 in Bc-Rc should be added to my
measurements published since IAUC 5736.  The supernova is now fading
in B, V, R, and I.  The shape of the lightcurve is almost symmetrical
around the secondary maxima, which from the OHP monitoring
are as follows:  Bc, 11.51, Apr. 16.7 UT; Vc, 10.87, 18.1; Rc,
10.52, 19.0; Ic, 10.43, 19.6."
     E. Guinan, J. Marshall, and G. McCook, Villanova University,
report on UBVRI photoelectric photometry of SN 1993J, conducted
with the FCC 0.8-m Automatic Photometry Telescope on Mt. Hopkins.
The observations have been obtained since Apr. 2 UT using HD 85458
and HD 86677 as comparison stars.  The observations show a local
light minimum at Apr. 5.1 +/- 0.5.  The star has gone through a
second wavelength-dependent light maximum.  The times of the
second light maximum in the U, B, V, R, and I bandpasses are Apr.
15.2, 16.5, 18.0, 18.6, and 19.0, respectively.  After Apr. 15, SN
1993J has rapidly decreased in brightness in the U bandpass.
     The following photometry (cf. IAUC 5750, 5755, 5758) by M.
Okyudo and T. Ishida, Nishi-Harima Astronomical Observatory (OI;
generally +/- 0.01 mag); by Guinan et al. (G; see above); and by
Prugniel (P; see above), are Johnson V magnitudes unless otherwise
noted:  Apr. 2.12 UT, 11.46 (G); 3.13, 11.67 (G); 4.13, 11.81 (G);
5, 11.84 (G); 7.14, 11.71 (G); 9.14, 11.53 (G); 10.13, 11.32 (G);
10.608, 11.46 (OI); 11.659, 11.30 (OI); 12.557, 11.24 (OI); 13.577,
11.17 (OI); 14.628, 11.03 (OI); 16.14, 11.00 (G); 16.601, 10.88
(OI); 17.15, 10.97 (G); 17.612, 11.00 (OI); 18.644, 10.97 (OI);
19.15, 10.98 (G); 19.634, 10.85 (OI); 20.16, 11.01 (G); 20.605,
11.04 (OI); 21.00, Vc = 10.96, Bc-Vc = +0.76, Vc-Rc = +0.40, Vc-Ic
= +0.50 (P).


1993 April 21                  (5770)            Daniel W. E. Green

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