Electronic Telegram No. 2875
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


COMET C/2011 U2 (BRESSI)
     Terry H. Bressi reports the discovery of a diffuse comet on CCD mosaic
images taken with the Spacewatch 0.9-m f/3 reflector at Kitt Peak (discovery
astrometry tabulated below); a short tail extends 7" from the central
condensation in p.a. 260 deg.  Follow-up observations by Bressi on Oct. 24.4
UT with the Spacewatch 1.8-m f/2.7 reflector confirm the tail length and
direction; additional images with the same telescope taken by Bressi and R. S.
McMillan through clouds on Oct. 26.2 show a 9" tail in p.a. 260 deg.  Stacked
R-band images taken by R. S. McMillan, J. V. Scotti, and D. Means on Oct.
24.37 with the Steward Observatory 2.3-m Bok telescope on Kitt Peak show a
coma diameter of 5" and a narrow, straight tail that extends 0'.26 in
brighter form, and faintly out to 0'.52, in p.a. 254 degrees.  After posting
on the Minor Planet Center's NEOCP webpage, E. Guido (Castellammare di Stabia,
Italy) writes that three stacked 60-s R-band exposures taken remotely on
Oct. 25.5 with the 2.0-m f/10 "Faulkes Telescope North" at Haleakala by D.
Cirelli, Guido, N. Howes, and G. Sostero show a compact coma about 4" x 3" in
size, elongated toward p.a. 250 deg, with a sharp central condensation and a
tail about 20" long in p.a. 250 deg.  R. Ligustri (Udine, Italy) finds total
red mag 18.8-18.9 and a thin tail 20"-25" long in p.a. about 250 deg on five
stacked 300-s images taken remotely on Oct. 26.2 with a 0.50-m f/4.5 reflector
located at the RAS Observatory near Mayhill, NM, U.S.A.

     2011 UT             R.A. (2000) Decl.       Mag.   Observer
     Oct. 24.20595    2 59 13.56   +25 10 56.7   19.4   Bressi
          24.22375    2 59 12.92   +25 10 54.1   19.4     "
          24.24155    2 59 12.44   +25 10 51.9   19.4     "

The available astrometry, the following preliminary parabolic orbital elements
by G. V. Williams, and an ephemeris appear on MPEC 2011-U85.

     T = 2012 Oct.  9.205 TT          Peri. = 222.890
                                      Node  = 263.794   2000.0
     q = 2.49387 AU                   Incl. =   9.813


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2011 CBAT
2011 October 26                  (CBET 2875)              Daniel W. E. Green