[IAUC] IAUC 9208: C/2011 J2; 251P [25139-2011/04-R1]

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                                                  Circular No. 9208
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
New postal address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
CBATIAU en EPS.HARVARD.EDU           ISSN 0081-0304
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Prepared using the Tamkin Foundation Computer Network


COMET C/2011 J2 (LINEAR)
     As first reported on CBET 2714, an apparently asteroidal
object discovered by the LINEAR survey (discovery observation
tabulated below), and posted on the Minor Planet Center's NEOCP
webpage, has been found by other CCD astrometrists to show cometary
appearance.  Juan Lacruz (Madrid, Spain) writes that sixty stacked
30-s images taken with a 0.40-m reflector at La Canada on May 5.9
UT show a diffuse object about 10" wide that is slightly elongated
toward the southeast (but no distinct tail).  H. Sato (Tokyo, Japan)
notes that images taken remotely with a 0.43-m f/6.8 reflector at
the RAS Observatory near Nerpio, Spain, on May 5.9 show the object
to be elongated; additional images taken remotely by Sato on May
6.2 with a 0.50-m f/4.5 reflector at the RAS Observatory near
Mayhill, NM, U.S.A., show a coma diameter of about 8" and a hint of
a fan-like tail extending 10" eastwards.  R. Holmes (Ashmore, IL,
USA) reports that co-added images taken by T. Linder, V. Hoette,
and himself with a 0.41-m f/11 reflector at Cerro Tololo on May 6.0
in 1".5 seeing show the object to be diffuse with a coma diameter
of 7".1, elongated in p.a. 73 deg.  J. V. Scotti (Lunar and
Planetary Laboratory) finds a coma diameter of 11" and a faint
0'.18 tail in p.a. 135 deg on six co-added frames taken on May 6.2
with the Spacewatch 1.8-m f/2.7 reflector.  R-band CCD frames taken
by W. H. Ryan and E. V. Ryan on May 7.12-7.15 with the Magdalena
Ridge Observatory 2.4-m f/8.9 reflector show a distinct coma (total
mag 19.1) with a tail in p.a. about 135 deg.

     2011 UT             R.A. (2000) Decl.       Mag.   Observer
     May   4.18905   10 50 06.11   - 8 27 24.5   19.7   LINEAR

The initial astrometry (including pre-discovery Mar. 10 and 25
Catalina observations, found by the MPC staff after posting on the
NEOCP) were published on MPEC 2011-J31; revised orbital elements
by G. V. Williams from MPC 75010:

                    Epoch = 2013 Dec. 14.0 TT
     T = 2013 Dec. 29.6479 TT         Peri. =  84.9167
     e = 0.998030                     Node  = 163.8811  2000.0
     q = 3.479486 AU                  Incl. = 122.9663


COMET 251P/LINEAR
     Comet P/2011 J1 = P/2004 HC_18 (cf. IAUC 9207) has been
assigned the permanent numeral designation 251P.

                      (C) Copyright 2011 CBAT
2011 May 20                    (9208)            Daniel W. E. Green