[Iaude] CBET 5136: COMET C/2022 L2

[quai at eps.harvard.edu]

                                                  Electronic Telegram No. 5136
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau at eps.harvard.edu (alternate cbat at iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET C/2022 L2 (ATLAS)
     P. Veres, Minor Planet Center, reports that A. Fitzsimmons notified the
MPC on June 10 of the discovery of an apparent new comet on four 30-s CCD
images taken with a 0.5-m f/2 Schmidt reflector at Mauna Loa, Hawaii, in the
course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search
program, with Fitzsimmons describing the object's image as "soft" with an
apparent coma of size 8" (full-width-at-half-maximum) in 6".0 seeing, adding
that background objects made the observation difficult.  The discovery
observations are tabulated below.

     2022 UT             R.A. (2000) Decl.       Mag.
     June 10.47539   19 29 56.35   +34 30 14.6   18.4
          10.47724   19 29 56.37   +34 30 15.3   18.3
          10.48000   19 29 56.11   +34 30 16.2   18.3
          10.48810   19 29 55.73   +34 30 17.4   18.5

After the object was posted on the MPC's PCCP webpage, other CCD astrometrists
have confirmed the cometary appearance.  Six stacked 120-s exposures taken
remotely by H. Sato (Tokyo, Japan) with a 0.43-m f/6.8 astrograph located at
Mayhill, NM, USA, on June 11.42 UT show a strongly condensed coma 8" in
diameter and no tail; the magnitude was 18.7 as measured within a circular
aperture of radius 5".7.  A. Valvasori, Padulle, Italy, writes that forty-nine
stacked 120-s unfiltered exposures taken remotely by E. Guido and himself with
a 0.30-m f/4 reflector at the ALMO Observatory in Padulle on June 11.9 show a
coma about 10" in diameter of mag 18.3.  E. Guido, Castellammare di Stabia,
Italy, writes that twenty-five 90-s unfiltered exposures obtained remotely by
a large group of observers using a "Telescope Live" 0.7 m f/8 Ritchey-Chretien
reflector at Oria, Spain, on June 12.0 show a diffuse coma about 7" in
diameter of mag 18.5-18.6.  Twenty stacked 120-s unfiltered exposures taken
on June 13.93-14.00 by E. Bryssinck, Kruibeke, Belgium, with a 0.4-m f/3.8
reflector in poor conditions show a central condensation with a coma of size
8" and no tail in a dense starfield.
     The available astrometry appears on MPEC 2022-M18.  The following
parabolic orbital elements by S. Nakano (Central Bureau) are from 173
observations spanning June 10-20 (mean residual 0".5).

     T = 2024 Mar. 17.23231 TT        Peri. = 198.63714
                                      Node  =  38.70167 2000.0
     q = 2.7567140 AU                 Incl. = 129.36779

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 8.0 and 2.5n = 8 for the magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2022 05 21    19 45.35   +33 07.9    6.417    6.712   102.6     8.5  18.7
2022 05 31    19 38.54   +33 53.4    6.248    6.640   108.5     8.3  18.6
2022 06 10    19 30.36   +34 28.9    6.092    6.567   113.8     8.1  18.5
2022 06 20    19 20.98   +34 51.3    5.954    6.495   118.1     7.9  18.4
2022 06 30    19 10.65   +34 58.1    5.837    6.423   121.2     7.8  18.3
2022 07 10    18 59.75   +34 47.2    5.742    6.350   122.8     7.7  18.2
2022 07 20    18 48.71   +34 17.8    5.670    6.277   122.7     7.8  18.2
2022 07 30    18 37.99   +33 30.3    5.623    6.205   120.8     8.1  18.1
2022 08 09    18 28.00   +32 26.2    5.600    6.132   117.3     8.4  18.0
2022 08 19    18 19.11   +31 08.4    5.598    6.059   112.6     8.9  18.0
2022 08 29    18 11.53   +29 40.1    5.615    5.986   106.8     9.3  18.0
2022 09 08    18 05.44   +28 05.0    5.647    5.913   100.4     9.6  17.9
2022 09 18    18 00.84   +26 26.7    5.690    5.840    93.6     9.9  17.9


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

                         (C) Copyright 2022 CBAT
2022 June 20                     (CBET 5136)              Daniel W. E. Green