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IAUC 6648: 1997 J2; V1974 Cyg

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                                                  Circular No. 6648
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
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COMET 1997 J2
     Michel Meunier reports his discovery of a new comet on May 7.9 UT,
only some 6' southwest of comet C/1997 J1, perhaps 0.5 mag brighter
than C/1997 J1 but having a much slower motion.  Additional observations,
apparently an independent discovery, have also been reported by
Philippe Dupouy and J. F. Lahitte.

     1997 UT             R.A. (2000) Decl.        m1    Observer
     May   7.91366   10 54 10.28   +73 53 08.6   14.0   Meunier
           7.92087   10 54 09.88   +73 53 07.6   13.9     "
           8.01956   10 54 04.71   +73 52 52.6   15.5   Dupouy
           8.05955   10 54 02.69   +73 52 46.3   15.5     "
           8.08126   10 54 01.62   +73 52 44.1   15.5     "
           8.88024   10 53 23.25   +73 50 46.7   14.2     "
           8.95490   10 53 19.28   +73 50 35.1   14.2     "

M. Meunier (Arbonne la Foret).  0.20-m f/6 reflector + CCD.
P. Dupouy and J. F. Lahitte (Observatoire de Dax).  0.20-m reflector + CCD.

     P. Garnavich and J. Raymond, Harvard-Smithsonian Center for
Astrophysics, report: "Narrow-band H-alpha imaging of the nebula associated
with V1974 Cyg = N Cyg 1992 (cf. IAUC 6441) shows that the region of
emission is apparently expanding away from the nova.  CCD images obtained
with the F. L. Whipple Observatory's 1.2-m reflector on 1996 Oct. 15 were
compared with data taken by P. Challis with the same equipment on 1997 May 5.
The difference between the frames shows that the brightest emission region,
about 2' southwest of the nova, has increased in extent by 10" to the
southwest.  A long, faint emission arc extending south of the nova around to
the east with a radius of 6'-7' is visible at both epochs.  The arc has
now increased in distance from the nova by about 30" to the southeast.
Another faint arc 4' to the west has brightened but has not significantly
changed position.  The shift of 30" over a 200-day interval is consistent
with the speed of light at distance of 1 kpc, suggesting that the changes
are not due to physical motion of the gas.  Spectra of the nebula southwest
of the nova were obtained on 1996 Oct. 14 with the Multiple-Mirror Telescope
and show only narrow Balmer emission.  Such a spectrum is inconsistent with
either reflection or ionization as the source of the emission.  Instead,
Lyman photons from the nova may be reprocessed by the ambient hydrogen in the
interstellar gas."

                      (C) Copyright 1997 CBAT
1997 May 8                     (6648)              Brian G. Marsden

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