Electronic Telegram No. 3969
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


DUST TRAIL OF COMET 17P/HOLMES
     P. M. Jenniskens forwards the following report:
     E. Lyytinen, M. Nissinen, H. J. Lehto, and J. Suomela, Helsinki, Finland,
report that the convergence of dust ejected by comet 17P/Holmes in 2007 is
now detected at the position in the orbit where it was originally released.
The dust trail was centered at R.A. = 4h57m28s, Decl. = +41d39'02" (equinox
2000.0) on Aug. 27d11h00m UT and oriented toward position angle 90.73 deg.
The detection was made with the Californian iTelescope T24, after subtracting
stacked images taken on Aug. 25 and 26 from those taken on Aug. 27.  The peak
surface brightness is 5.8 mag per square arcsecond fainter than the sky
background (assumed to be 21.0 mag per square arcsec).  This convergence is
expected to be visible during the coming year, even when the earth is not in
the plane of the comet orbit.  The surface brightness of the dust trail is
expected to increase until about Sept. 15.54, when the comet approaches the
point of its orbit where maximum dust outflow happened in 2007, and will only
gradually decrease in the months thereafter, with predicted coordinates for
the position of the trail given by Lyytinen et al. (2013, JIMO 41, 77-83).


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2014 CBAT
2014 September 7                 (CBET 3969)              Daniel W. E. Green