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IAUC 7064: P/1939 TN = 1998 WG22

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                                                  Circular No. 7064
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 P/1939 TN = 1998 WG22 (VAISALA-OTERMA)
     Precise positions of 1939 TN, an apparently asteroidal object
discovered by Y. Vaisala at Turku on 1939 Oct. 7 and observed by him and
L. Oterma on three more nights over a 35-day arc, were published in 1979
in Turku Obs. Report R10 and on MPC 4811.  The orbit computation by
Oterma suggested to her that the object was a comet, and in a communication
to the Minor Planet Center in 1981 she remarked that a careful reexamination
of the plates suggested that the object was perhaps somewhat diffuse.
The introduction to the 1982 edition of the Catalogue of Cometary Orbits
quotes her conclusion that the object was probably a comet, but the
object was not actually listed as one.  On MPEC 1998-X19, the object is
identified by S. Nakano, Sumoto, with 1998 WG22, an apparently
asteroidal object observed by the LINEAR program on Nov. 18 and 21:

     1998 UT             R.A. (2000) Decl.        m2
     Nov. 18.25966    3 40 20.80   +19 53 48.8   19.0

Fortuitously, this object was located only 4' from the result of
integrating forward from 1939 the orbital elements by the undersigned
on MPC 6815.  Further LINEAR observations were made on Nov. 24.
On observing the object with the 1.8-m reflector at the Dominion
Astrophysical Observatory on Dec. 6.3 UT, D. Balam noted (in FWHM 3".1
seeing) an 8" coma and a tail extending 18" in p.a. 260 deg.  On Dec. 7.1
W. Offutt, Cloudcroft, observing between clouds, also remarked on a
tail (or antitail) extending 17" in p.a. 257 deg, but no coma was noted.
M. Tichy, observing in poor conditions at Klet on Dec. 7.9, remarked
on a possible 6" coma.

     The object's cometary nature seems now reasonably assured, and the
following are Nakano's elements on MPEC 1998-X19 in "cometary" style:

                    Epoch = 1999 Jan. 22.0 TT
     T = 1998 Sept.27.2636 TT         Peri. = 165.3358
     e = 0.246318                     Node  = 242.4572  2000.0
     q = 3.391581 AU                  Incl. =   2.3399
       a =  4.500018 AU    n = 0.1032483    P =   9.546 years

1998/99     R. A. (2000) Decl.     Delta      r    Elong. Phase      m1
Dec.  3     3 30.68    +19 11.6    2.446    3.406  164.4    4.5     16.8
     13     3 25.25    +18 45.9    2.504    3.410  152.9    7.5     16.8
     23     3 21.35    +18 25.6    2.588    3.415  141.8   10.3     16.9
Jan.  2     3 19.34    +18 12.5    2.694    3.421  131.1   12.5     17.0

                      (C) Copyright 1998 CBAT
1998 December 7                (7064)              Brian G. Marsden

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