Electronic Telegram No. 3986
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 J2 (LINEAR)
     Z. Sekanina, Jet Propulsion Laboratory, reports that a modeling of the
companion's motion relative to the primary nucleus of C/2011 J2 (cf. CBET
3979), based on positional offsets (derived from the astrometry on MPECs
2014-R69 and 2014-R70 = MPC 89407-89408; and MPEC 2014-S34), suggests that the
companion, a strongly decelerating fragment (about 0.0008 the sun's
gravitational acceleration) of a fairly short lifetime (estimated at 20-40
days at 1 AU from the sun; for definition, cf. Sekanina 1982, in *Comets*, ed.
by L. L. Wilkening, Univ. of Arizona Press, p. 251), separated with a sub-
meter velocity from the parent some 2 weeks after perihelion, in early January
2014.  The solution is somewhat uncertain because the observations span a
period of time nearly centered on the earth's transit across the comet's orbit
plane, which occurred on 2014 Sept. 6.8 TT.  Predicted separation distances
and position angles of the companion relative to the primary are as follows
(0 TT; equinox 2000.0):  2014 Sept. 20, 11".9, 15 deg; Oct. 10, 17".5, 18 deg;
Oct. 30, 23".2, 18 deg; Nov. 19, 27".4, 17 deg; Dec. 9, 30".2, 16 deg; and
Dec. 29, 31".8, 15 deg.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2014 CBAT
2014 September 24                (CBET 3986)              Daniel W. E. Green