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IAUC 8967: P/2008 Q2; eta Car

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                                                  Circular No. 8967
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 P/2008 Q2 (ORY)
     An apparently asteroidal object discovered by Michel Ory
(Delemont, Switzerland, on CCD images obtained with a 0.61-m f/3.9
reflector at Vicques; discovery observation tabulated below), which
was posted on the Minor Planet Center's 'NEOCP' webpage, has been
found by other CCD observers to be cometary.  A. Knoefel
(Schoenbrunn, Germany, 0.5-m reflector, Aug. 28.0 UT) reports an
apparent faint coma.  L. Buzzi (Varese, Italy, 0.60-m reflector,
Aug. 28.1) notes a 12" coma elongated to the southwest, adding that
his inspection of stacked astrographic images taken by R. Holmes
(Charleston, IL, U.S.A., Aug. 28.28) reveals a coma about 20" wide
that is elongated in p.a. 240 deg.  A. C. Gilmore and P. M.
Kilmartin remark that two stacked 120-s CCD frames taken with the
1.0-m f/7.7 reflector at Mt. John on Aug. 28.6 show a condensed,
circular coma of diameter 14" with no tail.

     2008 UT             R.A. (2000) Decl.       Mag.
     Aug. 27.09470    1 32 40.74   + 3 04 17.2   17.6

The available astrometry, the following preliminary elliptical
orbital elements, and an ephemeris appear on MPEC 2008-Q51.

     T = 2008 Oct. 23.018 TT          Peri. = 334.141
     e = 0.58310                      Node  =  59.478   2000.0
     q = 1.37046 AU                   Incl. =   2.814
       a =  3.28723 AU     n = 0.165370     P =   5.96 years

     A. Damineli -- on behalf of a large team monitoring eta Car
spectroscopicaly at the Observatories of Pico dos Dias (Brazil),
Casleo (Argentina), Las Campanas, and European Southern Observatory,
La Silla -- reports measurements in the He II 468.6-nm emission line.
The equivalent width was 0.009 nm at epochs 2007.3 and 2007.6, 0.012
nm at 2008.3, and 0.021 nm at 2008.6 -- repeating very well the past
cycle, as reported by Steiner and Damineli (2004, Ap.J. 612, L133).
The fact that the line-intensity curve follows the x-ray light curve
indicates that the He II emitting region is associated with the
wind-wind collision shock and not driven by a sudden shell ejection.
For related information, see also Damineli et al. 2008,
MNRAS 386, 2330.

                      (C) Copyright 2008 CBAT
2008 August 28                 (8967)            Daniel W. E. Green

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