Electronic Telegram No. 5144
Central Bureau for Astronomical Telegrams
Mailing address:  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/2022 L4 (PANSTARRS)
     An apparently asteroidal object discovered on June 4 (discovery
observations tabulated below) in images obtained with the Pan-STARRS2 1.8-m
Ritchey-Chretien reflector at Haleakala, HI, USA, has been found to show
cometary activity.

     2022 UT             R.A. (2000) Decl.       Mag.
     June  4.39626   17 04 16.67   -12 19 59.4   21.4
           4.40654   17 04 15.08   -12 20 04.0   21.0
           4.41688   17 04 13.46   -12 20 08.1   21.8
           4.42718   17 04 11.89   -12 20 12.2   20.8
           4.48439   17 04 02.91   -12 20 36.0   21.5
           4.48502   17 04 02.81   -12 20 36.4   21.3

R. Weryk, Department of Physics and Astronomy, University of Western Ontario,
writes that he and R. Wainscoat obtained three 60-s gri-band images with the
3.6-m Canada-France-Hawaii Telescope at Mauna Kea (queue observer L. Wells;
coordinator H. Flewelling) on June 27.26 UT that show a condensed head of size
0".8 (full-width-at-half-maximum) in 0".7 seeing with a clear, braod tail 4"
long spanning p.a. 60-110 degrees.  Twenty-six stacked 60-s CCD exposures
taken remotely by H. Sato (Tokyo, Japan) on June 20.54-20.55 UT with a 0.51-m
f/6.8 astrograph located at Siding Spring show the object to be stellar in
appearance; the magnitude was 20.7 as measured within a circular aperture of
radius 3".2.
     The available astrometry appears on MPEC 2022-M104.  The following
parabolic orbital elements by S. Nakano (Central Bureau) are from 43
observations spanning June 4-27 (mean residual 0".4), and suggest that the
comet passed 3.25 AU from Jupiter on 2021 Aug. 24 UT.

     T = 2021 Dec.  9.94711 TT        Peri. = 125.56866
                                      Node  =  66.02580 2000.0
     q = 3.0207838 AU                 Incl. = 141.28959

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 14.0 and 2.5n = 8 for the
magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2022 05 21    17 40.73   -10 39.6    2.487    3.412   151.7     8.1  20.2
2022 05 31    17 15.60   -11 49.6    2.468    3.458   165.2     4.3  20.3
2022 06 10    16 49.95   -12 57.5    2.504    3.505   168.8     3.2  20.4
2022 06 20    16 25.57   -13 59.9    2.595    3.554   157.3     6.3  20.5
2022 06 30    16 03.91   -14 55.4    2.736    3.605   143.6     9.6  20.6
2022 07 10    15 45.77   -15 45.2    2.918    3.657   130.2    12.3  20.8
2022 07 20    15 31.37   -16 30.9    3.130    3.711   117.6    14.0  21.0
2022 07 30    15 20.48   -17 14.6    3.362    3.766   105.7    15.0  21.2
2022 08 09    15 12.71   -17 57.7    3.607    3.822    94.5    15.3  21.4
2022 08 19    15 07.58   -18 41.1    3.854    3.880    83.9    15.0  21.6
2022 08 29    15 04.62   -19 25.6    4.098    3.939    73.8    14.3  21.8
2022 09 08    15 03.45   -20 11.2    4.334    3.998    64.1    13.1  22.0
2022 09 18    15 03.70   -20 58.0    4.556    4.059    54.7    11.7  22.2


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

                         (C) Copyright 2022 CBAT
2022 June 30                     (CBET 5144)              Daniel W. E. Green