Electronic Telegram No. 4111
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 P/2015 J4 = P/2009 L2 (YANG-GAO)
     H. Sato, Tokyo, Japan, reports his recovery of comet P/2009 L2 (cf. IAUC
9052) on CCD images obtained with an 0.51-m f/6.8 astrograph (+ luminance
filter) at Siding Spring.  The comet appeared stellar on May 11 in ten stacked
60-s exposures; the w-band magnitude tabulated below for that date was
measured within a circular aperture of radius 6".6.  The comet appeared
cometary on June 9, with a faint outer coma 15" in diameter and a fan-like
tail 30" long spanning p.a. 45-135 degrees in eight stacked 60-s exposures;
the tabulated magnitude for June 9 were measured within a circular aperture
of radius 8".8.  Eight stacked 60-s follow-up exposures by Sato on June 10.36
UT show the comet to be moderately condensed with a faint coma 12" in
diameter and a fan-like tail 20" long spanning 40-130 degrees; he measured
magnitude 18.3 within a circular aperture of radius 6".6.

     2015 UT             R.A. (2000) Decl.       Mag.   Observer
     May  11.38368    9 21 24.94   - 6 48 01.6          Sato
          11.38579    9 21 25.07   - 6 48 00.8            "
          11.38790    9 21 25.23   - 6 48 00.2   19.1     "
     June  9.37566   10 12 16.84   - 6 25 38.3            "
           9.37736   10 12 17.04   - 6 25 38.3            "
           9.37905   10 12 17.25   - 6 25 38.9   18.6     "

The indicated correction to the prediction by B. G. Marsden on MPC 79350 is
Delta(T) = +0.10 day.
     The following linked orbital elements by G. V. Williams are from 1052
observations spanning 2009 June 15-2015 June 9 (mean residual 0".5).
Additional elements and an ephemeris appear on MPEC 2015-L28.

                    Epoch = 2015 Aug.  6.0 TT
     T = 2015 Aug. 15.13638 TT        Peri. = 343.56508
     e = 0.5936996                    Node  = 257.62554 2000.0
     q = 1.4310835 AU                 Incl. =  16.69224
       a =  3.5222304 AU   n = 0.14909993   P =   6.61 years


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2015 CBAT
2015 June 10                     (CBET 4111)              Daniel W. E. Green