Electronic Telegram No. 5183
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 U1 (LEONARD)
G. J. Leonard, Lunar and Planetary Laboratory, University of Arizona,
reports his discovery of another comet on CCD images obtained on Oct. 20 UT
with the Mt. Lemmon 1.5-m reflector (discovery observations tabulated below);
he noted a strongly condensed coma about 8" across with some diffuseness and
no apparent tail in four 30-s co-added images.
2022 UT R.A. (2000) Decl. Mag. Observer
Oct. 20.33718 4 32 11.28 +33 25 34.0 19.8 Leonard
20.34233 4 32 11.00 +33 25 35.4 19.8 "
20.34748 4 32 10.69 +33 25 36.4 20.0 "
20.35262 4 32 10.41 +33 25 37.9 19.9 "
After the comet was posted on the Minor Planet Center's PCCP webpage, F. Kugel
found a 7" tail in p.a. 232 degrees in seven 120-s unfiltered CCD images taken
on Oct. 27.1 UT with a 0.4-m f/2.8 reflector at Dauban, France; the magnitude
was 19.4-20.0 in an aperture of radius 5".8. However, ten stacked 120-s CCD
exposures taken remotely by H. Sato (Bunkyo-ku, Tokyo, Japan) with a 0.43-m
f/6.8 astrograph located at Mayhill, NM, USA, on Oct. 20.4 show only a
stellar appearance; the magnitude was 19.6 as measured within a circular
aperture of radius 5".7.
The available astrometry appears on MPEC 2022-U343 and 2022-U349,
including pre-discovery observations (found subsequent to Leonard's discovery
report) that were made on Sept. 23.45 UT at Mt. Lemmon (mag 20.2-20.3;
observer K. W. Wierzchos) and on Oct. 19.03-19.06 at Nauchnij, Crimea (mag
19.7-20.1; observer G. Borisov). The following parabolic orbital elements by
S. Nakano (Central Bureau) are from 55 observations spanning Sept. 23-Oct. 28
(mean residual 0".3). The orbit is overly dependent upon the Sept. 23
observations, with no additional observations being available until Oct. 19.
T = 2024 Mar. 25.47118 TT Peri. = 78.53929
Node = 72.50219 2000.0
q = 4.2010637 AU Incl. = 128.12890
The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 9.5 and 2.5n = 8 for the
magnitudes.
Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag.
2022 09 18 04 53.15 +30 55.9 5.898 6.138 99.1 9.3 19.7
2022 09 28 04 48.71 +31 43.2 5.673 6.083 109.6 8.9 19.5
2022 10 08 04 42.47 +32 30.3 5.461 6.028 120.4 8.2 19.4
2022 10 18 04 34.36 +33 15.5 5.267 5.974 131.4 7.2 19.3
2022 10 28 04 24.38 +33 56.6 5.099 5.920 142.6 5.9 19.2
2022 11 07 04 12.72 +34 31.1 4.963 5.866 153.4 4.3 19.1
2022 11 17 03 59.75 +34 56.7 4.862 5.813 162.4 2.9 19.0
2022 11 27 03 45.99 +35 11.6 4.801 5.760 164.9 2.6 19.0
2022 12 07 03 32.11 +35 15.7 4.780 5.707 158.3 3.7 18.9
2022 12 17 03 18.80 +35 10.0 4.798 5.655 147.8 5.3 18.9
2022 12 27 03 06.63 +34 56.9 4.850 5.603 136.4 7.0 18.9
2023 01 06 02 56.06 +34 39.9 4.932 5.552 124.8 8.4 18.9
2023 01 16 02 47.31 +34 22.1 5.036 5.502 113.4 9.4 18.9
2023 01 26 02 40.47 +34 06.6 5.156 5.451 102.3 10.2 19.0
2023 02 05 02 35.48 +33 55.6 5.283 5.402 91.6 10.5 19.0
2023 02 15 02 32.20 +33 50.7 5.412 5.353 81.3 10.5 19.0
2023 02 25 02 30.45 +33 52.7 5.536 5.304 71.4 10.2 19.0
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2022 CBAT
2022 October 29 (CBET 5183) Daniel W. E. Green