Archive for July 20th, 2011

CBET 2768: COMET P/2011 NO1

                                                  Electronic Telegram No. 2768
Central Bureau for Astronomical Telegrams
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail: (alternate
Prepared using the Tamkin Foundation Computer Network

COMET P/2011 NO1
     L. Elenin (Lyubertsy, Russia) and I. Molotov (Moscow, Russia) report
their discovery of an object with slight apparent cometary appearance
on four 240-s unfiltered CCD exposures taken remotely with a 0.45-m f/2.8
astrograph at the ISON-NM observatory near Mayhill, NM, USA, on July 7.3 UT
(discovery observation tabulated below).  After posting on the Minor Planet
Center's NEOCP webpage, several other CCD astrometrists have also commented
on the object's cometary appearance.  Stacked images taken by R. Holmes
(Ashmore, IL, USA; 0.61-m f/4.0 astrograph; measured by S. Foglia and T.
Vorobjov) on July 9.26 UT show a possible coma out to 8", while similar
images taken on July 11.25 show an elongated shape 8" x 5" in shape extended
in p.a. 247 deg; similar images from July 12.3 show the comet to be diffuse
and of similar size (though no elongation mentioned).  Foglia also adds that
eight stacked 60-s images taken by P. Miller, P. Roche, A. Tripp, R. Holmes,
R. Miles, L. Buzzi, and himself with the 2.0-m f/10 Ritchey-Chretien "Faulkes
Telescope North" at Haleakala (and measured by Buzzi and Foglia) on July
13.6 show a diffuse coma of size 4" x 7", elongated in p.a. 244 deg.  L. Buzzi
(Varese, Italy, 0.38-m f/6.8 reflector; July 12.04-12.07) writes that stacked
images taken in a hazy sky and at low altitude show the object to be diffuse,
with the center of light difficult to measure.  N. Howes, G. Sostero, and E.
Guido report that thirteen stacked 20-s R-band images taken remotely with the
2.0-m f/10 Ritchey-Chretien "Faulkes Telescope South" at Siding Spring on July
12.5 in good seeing shows a coma about 2" in diameter, elongated toward the
southwest, with a narrow 3" tail toward p.a. 250 deg.  H. Sato (Tokyo, Japan)
reports that images taken remotely with a 0.43-m f/6.8 reflector at Nerpio,
Spain, in moonlight on July 14.0 show a diffuse coma 6" in diameter of red
mag 18.6, with no tail visible.

     2011 UT             R.A. (2000) Decl.       Mag.   Observer
     July  7.30144   20 22 49.05   -19 39 34.9   19.5   Elenin

     This object was announced by T. Spahr as a minor planet on MPEC
2011-O09 while a CBET was being prepared to announce it as a comet, and he
assigned the designation 2011 NO1 to it.  The available astrometry, the
following preliminary elliptical orbital elements by G. V. Williams, and
an ephemeris appear on MPEC 2011-O10.

     T = 2011 Jan. 22.0172 TT         Peri. = 264.0650
     e = 0.775686                     Node  = 296.0592  2000.0
     q = 1.244833 AU                  Incl. =  15.0324
       a =  5.549505 AU    n = 0.0753916    P =  13.07 years

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

                         (C) Copyright 2011 CBAT
2011 July 19                     (CBET 2768)              Daniel W. E. Green
July 2011
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