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IAUC 6500: 1996bq; COMETS C/1995 O1 (HALE-BOPP) AND 126P/IRAS

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                                                  Circular No. 6500
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
Phone 617-495-7244/7440/7444 (for emergency use only)

     C. Pollas, Observatoire de la Cote d'Azur (OCA), reports his
discovery of an apparent supernova on OCA films taken on Oct. 12.05
and 12.11 UT.  SN 1996bq located is at R.A. = 2h38m40s.03, Decl. =
+41o39'17".8 (equinox 2000.0), which is 0".6 east and 27".4 north
of the center of NGC 996.  Nothing appears at this position on the
original Palomar Sky Survey prints, on a second Sky Survey B film,
or on 1995 OCA films.  A recent deeper OCA film shows that the
object has faded, as indicated by the following V magnitudes:  Oct.
12.1, 18.7; Nov. 3.9, 19.4.  A nearby star (V about 18.5) has
position end figures 40s.07, 12".6.

     D. Lynch, R. Russell, and T. Tessensohn, Aerospace Corporation;
M. Sitko, University of Cincinnati; and M. Hanner, Jet Propulsion
Laboratory, report 8-13-micron spectroscopy of comet C/1995 O1 on
Oct. 14.25 UT using the Infrared Telescope Facility (+ Aerospace
BASS spectrograph) with a 3".4 beam and a 60" chop throw:  "The
comet's central condensation showed a strong silicate emission
feature with a line/continuum ratio of 1.5.  The gross shape of the
silicate emission closely resembles the now-familiar trapezoidal
feature previously seen in comets 1P/Halley, C/1987 P1 (Bradfield),
and C/1990 K1 (Levy).  The feature also showed significant spectral
structure with a peak at 11.2 +/- 0.1 microns (0.4 micron wide,
FWHM) and potentially a second peak at 10.1 +/- 0.1 microns (0.3
micron wide).  The 8-12.5-micron color temperature was 255 +/- 15 K,
or about 85 K above the radiative equilibrium temperature (168 K)
for a blackbody at heliocentric distance of 2.73 AU.  Magnitudes at
8.0, 10.5, and 12 microns were 3.9 +/- 0.1, 1.20 +/- 0.06, and 1.16
+/- 0.1, respectively.  On Oct. 16.25, the spectrum was the same
shape as before but about 10 percent brighter.  Photometry of comet
126P/IRAS was obtained on Oct. 15.3 with the same instrument; by
averaging spectroscopic points between 10 and 13 microns, they
obtained a positive detection of N' = 2.7 +/- 0.19 under poor seeing
     Visual m1 estimates of C/1995 O1:  Oct. 8.39 UT, 5.0 (D.
Seargent, The Entrance, N.S.W., naked eye); 13.74, 4.9 (M. Plsek,
Lelekovice, Czech Rep., 10x50 binoculars); 29.74, 5.2 (R. J. Bouma,
Groningen, The Netherlands, 7x50 binoculars); Nov. 1.76, 4.9 (R.
Haver, Frasso Sabino, Italy, 10x50 binoculars); 3.71, 4.7 (V.
Znojil, Brno, Czech Rep., naked eye).

                      (C) Copyright 1996 CBAT
1996 November 4                (6500)            Daniel W. E. Green

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