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IAUC 6825: C/1997 U1; V4334 Sgr; 55P

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                                                 Circular No. 6825
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)


COMET C/1997 U1 (SOHO)
     C. St. Cyr, Naval Research Laboratory, on behalf of the SOHO-
LASCO Consortium (cf. IAUC 6685), reports the discovery by D. A.
Biesecker, University of Birmingham, of another comet in archival
C3 coronagraphic data.  The comet reached an estimated peak
magnitude of 7.3 and never developed a tail.  Measurements by
Biesecker and St. Cyr have been reduced by G. V. Williams and are
published in detail on MPEC 1998-D09, together with an orbit
solution by B. G. Marsden.

     1997 UT           R.A. (2000) Decl.
     Oct. 28.134      13 53.6      -16 24


V4334 SAGITTARII
     W. Liller, Instituto Isaac Newton, Vina del Mar, Chile; M.
Janson, Groningen University; H. W. Duerbeck, Muenster University;
and A. van Genderen, Leiden University, report that this object (cf.
IAUC 6718) has faded by almost 2 mag since last November, indicating
that the predicted dust formation (Duerbeck et al. 1997, A.J. 114,
1657) from the presumed final helium flash has begun.  During 1997
Mar.-Nov., the star was between V = 10.75 and 11.0.  Subsequent V
magnitudes by Liller (L; 0.2-m telescope) and by Janson (J; ESO
Dutch 0.9-m telescope):  1997 Nov. 21.02 UT, 10.76 (L); 1998 Feb.
9.37, 11.96 (L); 10.35, 11.90 (L); 14.38, 12.73 (J); 15.38, 12.75
(J); 17.36, 12.74 (J).  The star has also become generally redder;
between 1997 Sept. 14 and 1998 Feb. 15, U-B changed from +0.83 to
+1.12, B-V from +1.66 to +1.51, V-R from +1.11 to +1.71, and V-i
(Gunn i) from 2.08 to 2.86.  Multicolor optical monitoring is being
carried out, and infrared photometry is encouraged.


COMET 55P/TEMPEL-TUTTLE
     Total visual magnitude estimates:  Feb. 1.00 UT, 8.3 (J. E.
Bortle, Stormville, NY, 20x80 binoculars); 3.3, 7.9 (S. J. O'Meara,
Volcano, HI, 0.10-m refractor); 6.83, 8.3 (A. Pereira, Cabo da
Roca, Portugal, 14x100 binoculars); 12.77, 8.4 (B. H. Granslo,
Movatn, Oslo, Norway, 0.07-m refractor); 17.46, 8.4 (M. Mattiazzo,
Wallaroo, S. Australia, 0.20-m reflector); 20.76, 8.7 (M. Meyer,
Frauenstein, Germany, 0.25-m reflector).

                      (C) Copyright 1998 CBAT
1998 February 20               (6825)            Daniel W. E. Green

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