IAUC 6403
Circular No. 6403
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 1996aa IN NGC 5557
W. Johnson, Anza, CA, reports his discovery of a supernova
(mag about 17) on two CCD image exposed on May 16 UT. The new star
is located about 5" northwest the center of NGC 5557 (R.A. =
14h18m.4, Decl. = +36o30', equinox 2000). SN 1996aa is not
present on a Carnegie Atlas print or on a slightly-out-of-focus CCD
image taken by Johnson in 1995. There is a foreground star of mag
about 15 located on the opposite side of the galaxy, about 15"
south-southeast from the galaxy nucleus.
P. Garnavich, A. Riess, and R. Kirshner, Harvard-Smithsonian
Center for Astrophysics, report that a spectrogram was obtained by
E. Barton with the 1.5-m Tillinghast telescope on May 19.26 UT,
showing that this is a type-Ia supernova, 6-8 weeks past maximum.
SN 1996aa appears 5" west and 3" north of the galaxy's center.
COMET C/1995 O1 (HALE-BOPP)
D. J. Osip, R. K. Pina, C. M. Telesco, and R. S. Fisher,
University of Florida (UF); and M. S. Hanner, Jet Propulsion
Laboratory, report the first mid-infrared detections of comet
C/1995 O1, using the UF/NASA imager/spectrometer (OSCIR; field-of-
view 28" x 28") at the Infrared Telescope Facility on May 19.7 UT,
with the comet at a heliocentric distance of 4.36 AU. Images were
obtained with the broadband N (10.8-micron) and the IHW 18-micron
filters. Preliminary data reduction yields flux densities
(integrated over a 3".25 box aperture) of 1.16 +/- 0.02 Jy at 10.8
microns and 3.35 +/- 0.19 Jy at 18 microns. The uncertainties
represent noise statistics and do not include photometric
uncertainties of about 10 percent. These flux densities indicate a
bandwidth-corrected color temperature of 224 K, compared to the
blackbody equilibrium temperature at 4.36 AU of 133 K.
SUPERNOVA 1996Z IN NGC 2935
S. Nakano, Sumoto, Japan, reports the following precise
position for SN 1996Z measured by Y. Kushida from a CCD image
obtained by R. Kushida, Yatsugatake South Base Observatory, on May
18.463 UT: R.A. = 9h36m44s.82, Decl. = -21o08'51".7 (equinox
2000.0). The magnitude of SN 1996Z was measured to be V = 14.2.
(C) Copyright 1996 CBAT
1996 May 20 (6403) Daniel W. E. Green
CBAT