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IAUC 7299: 141P

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                                                  Circular No. 7299
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  ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)


COMET 141P/MACHHOLZ 2
     On Oct. 17 R. H. McNaught, Research School of Astronomy and Astrophysics,
Siding Spring Observatory, reported his single-night detection of another
component of this comet, with m2 fainter by 0.5 mag but with brighter m1
and a larger coma (diameter 8", as opposed to 5") that night than the object
reported on IAUC 7231 (presumed to be the 1994 component A, which he
measured to be 260" to the east and 346" to the north).  It seemed likely
that the new object was component D.  On Oct. 23 S. Nakano reported an
independent detection of the new component by A. Sugie, Dynic Observatory,
on Oct. 21 (m1 = 16.2, coma 10") and 23 (m1 = 17.3), and calculations by him
and by the undersigned confirmed this to be component D, linkable to the
complete 1994 arc without allowance for nongravitational effects.  October
astrometry and linked orbital elements are given on MPC 36175 and 36213, the
Delta T difference from component A (for which Nakano gave on MPC 35815 a
complete 1994-1999 linkage using three nongravitational components) being
+0.69 day.  McNaught searched for but failed to find component D on images
obtained on Oct. 6 and 7, when it must have been at least 1 mag fainter than
component A.  On Oct. 31 H. Luthen, Hamburg, reported the photographic
detection by M. Jager, Vienna, on Oct. 27 and by Jager and G. Rhemann on
Oct. 29 and 31 of an object with a 1'.5-2'.0 coma and m1 = 12.8-13.0.
Astrometry by E. Meyer, E. Obermair and H. Raab, Linz, on Nov. 1 confirms
this also to have been component D, with coma 0'.5 and m1 = 15.4.  The MPC
36213 elements for component D and an ephemeris follow (the predicted
magnitude being very uncertain):

                    Epoch = 1999 Dec.  8.0 TT
     T = 1999 Dec.  9.9624 TT         Peri. = 149.2961
     e = 0.751113                     Node  = 246.1392  2000.0
     q = 0.748957 AU                  Incl. =  12.8128
       a =  3.009220 AU    n = 0.1888092    P =   5.220 years

1999 TT     R. A. (2000) Decl.     Delta      r    Elong. Phase      m1
Oct. 29    18 05.71    -11 59.6    1.129    1.021   57.1   54.8     13.0
Nov.  3    18 18.66    -11 58.7    1.088    0.970   55.3   57.3     12.3
      8    18 32.58    -11 55.6    1.042    0.921   53.8   60.2     11.5
     13    18 47.52    -11 50.3    0.991    0.877   52.5   63.6     10.8
     18    19 03.49    -11 43.4    0.936    0.837   51.5   67.5     10.0
     23    19 20.55    -11 35.7    0.877    0.803   50.6   71.9      9.4
     28    19 38.75    -11 28.7    0.814    0.777   50.0   76.6      8.8

                      (C) Copyright 1999 CBAT
1999 November 1                (7299)              Brian G. Marsden

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