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IAUC 8558: 9P; P/2005 M1

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                                                  Circular No. 8558
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)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)

     C. W. Hergenrother, J. R. Weirich, and J. Keller, Lunar and
Planetary Laboratory, University of Arizona, report the results of
aperture photometry on the inner coma of comet 9P/Tempel with the
Kuiper 1.54-m reflector via a series of 30- and 60-s R-band
integrations.  The inner coma experienced a rapid brightening
immediately after the impact by the 'Deep Impact' spacecraft onto
the comet's surface (around July 4.244 UT).  The brightening began
to level off approximately 15 min after impact.  By the time the
comet was no longer observable, 70 min after impact, the
brightening appeared to have plateaued.  The following brightness
increases were observed in apertures of varying diameters:  2".6,
2.15 mag; 3".5, 2.04 mag; 4".4, 1.92 mag; 5".2, 1.82 mag; 6".1,
1.74 mag; 7".0, 1.67 mag.  The brightening was confined to the
seeing disk of the pseudo-nucleus.
     J. McGaha, Tucson, AZ, reports that comet 9P was observed with
a low-light PC-164 video camera (exposing at 30 frames/s; spectral
sensitivity peaking around 500-600 nm) attached to his 0.20-m f/4
reflector during July 4.240-4.257 UT; no flash was observed around
the time of impact by the 'Deep Impact' spacecraft.  Also, 90-s CCD
images taken with a 0.62-m reflector during July 4.240-4.302 show
no changes, the coma and tail showing very well in these images.
     Total visual magnitude estimates by M. Linnolt (Woodside, CA,
0.20-m reflector), while the coma diameter remained steady at 2'.2:
July 4.2368 UT, 11.2; 4.2451, 11.2; 4.2500, 11.1; 4.2583, 10.9;
4.2674, 10.7.
     M. Kidger, Instituto de Astrofisica de Canarias, reports that
his "Observadores cometas" group has obtained almost 2000 CCD
photometric points of the light curve of 9P/Tempel since October
2004.  There is a strong suggestion of a periodic rapid rise and
slow decline, with the best-fit period being approximately 4.40 +/-
0.05 days, in both the light curve and in dust production measured
as Af(rho), that is presumably precessional.

     Additional astrometry and the following improved elliptical
orbital elements appear on MPEC 2005-N20.

     T = 2006 Jan. 31.809 TT          Peri. = 226.708
     e = 0.30668                      Node  = 143.046   2000.0
     q = 2.91826 AU                   Incl. =  10.149
       a =  4.20910 AU     n = 0.114135     P =   8.64 years

                      (C) Copyright 2005 CBAT
2005 July 4                    (8558)            Daniel W. E. Green

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