[Iaude] CBET 5316: COMET C/2023 V5

[quai at eps.harvard.edu]

                                                  Electronic Telegram No. 5316
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/2023 V5 (LEONARD)
     Gregory J. Leonard, Lunar and Planetary Laboratory, University of
Arizona, reports his discovery of another comet on images obtained on Nov. 6
UT with the Catalina Sky Survey's 0.68-m Schmidt telescope (discovery
observations tabulated below).  The comet showed a moderately condensed coma
10" across with no apparent tail in four co-added 30-s exposures.

     2023 UT             R.A. (2000) Decl.       Mag.   Observer
     Nov.  6.14346   22 17 57.49   - 8 47 42.1   17.4   Leonard
           6.14852   22 17 51.86   - 8 46 39.7   17.7     "
           6.15358   22 17 46.19   - 8 45 38.3            "
           6.15865   22 17 40.47   - 8 44 37.0   17.8     "

After the comet was posted to the Minor Planet Center's PCCP webpage, other
CCD astrometrists have also commented on the cometary appearance.  A. C.
Gilmore and P. M. Kilmartin write that images taken on Nov. 6.4 UT with the
Mount John University Observatory 1.0-m f/7.7 reflector show a coma diameter
of 7" with a diffuse edge in p.a. 60 degrees; magnitudes of 18.3-19.1 were
measured in an 11" aperture.  Sixteen stacked 15-s exposures taken by K.
Yoshimoto (Kumage, Yamaguchi, Japan) with a 0.51-m f/6.8 reflector located at
Siding Spring, NSW, Australia, on Nov. 6.49 show a diffuse coma 15" in
diameter of total magnitude 17.8 with no tail.  Thirty stacked 8-s exposures
taken remotely by H. Sato (Bunkyo-ku, Tokyo, Japan) with a 0.51-m f/6.8
astrograph located at Siding Spring on Nov. 6.53-6.58 show a strongly
condensed coma 12" in diameter with no tail; the magnitude was 17.9 as
measured within a circular aperture of radius 6".5.  Three-hundred-forty-two
stacked 8-s exposures taken on Nov. 7.7 by A. Aletti (and measured by M.
Auteri and Aletti) with a 0.36-m f/7.5 reflector at Varese, Italy, show this
object to be clearly a comet with a slightly condensed 8" coma of mag 18.2
and a faint, straight tail at least 15" long in p.a. 75 degrees.  One-
hundred stacked 13-s exposures taken by L. Buzzi and G. Galli with a 0.84-m
f/3.5 reflector at Varese (measured by Buzzi, Galli, and Aletti) on Nov. 7.8
show a moderately diffuse 8" coma with a tail 15" long in p.a. 75 degrees.
     R. Bouma, Groningen, The Netherlands, notes that this comet's orbital
elements appear similar to that of the C/1988 A1 group of comets that also
includes C/1996 Q1, C/2015 F3, and C/2019 Y1.  The available astrometry
appears on MPEC 2023-V193.  The following preliminary parabolic orbital
elements by S. Nakano (Central Bureau) are from 114 observations spanning
Nov. 6-10 (mean residual 0".7); these elements indicate that the comet passed
0.22 AU from the earth on 2023 Nov. 4 UT.

     T = 2023 Dec. 14.08199 TT        Peri. =  57.23504
                                      Node  =  31.55731 2000.0
     q = 0.8447278 AU                 Incl. =  73.39038

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 21.0 and 2.5n = 8 for the
magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2023 10 23    02 44.99   -35 47.6    0.358    1.260   131.2    36.5  19.6
2023 10 28    01 29.71   -32 55.6    0.274    1.199   133.4    37.1  18.8
2023 11 02    23 43.95   -22 38.6    0.227    1.139   125.6    45.1  18.2
2023 11 07    22 02.72   -05 56.0    0.237    1.083   106.6    61.3  18.2
2023 11 12    20 53.49   +07 29.4    0.298    1.030    89.2    74.0  18.5
2023 11 17    20 10.27   +15 26.4    0.384    0.982    77.7    79.8  18.9
2023 11 22    19 41.96   +20 05.2    0.479    0.939    70.0    81.4  19.2
2023 11 27    19 21.86   +22 56.6    0.578    0.903    64.4    80.4  19.5
2023 12 02    19 06.50   +24 45.2    0.675    0.874    60.1    77.9  19.7
2023 12 07    18 54.06   +25 53.1    0.769    0.855    56.7    74.5  19.9
2023 12 12    18 43.58   +26 32.5    0.858    0.846    54.1    70.6  20.1
2023 12 17    18 34.52   +26 50.9    0.940    0.846    52.1    66.6  20.3
2023 12 22    18 26.57   +26 53.7    1.014    0.858    50.8    62.7  20.5
2023 12 27    18 19.55   +26 45.3    1.080    0.878    50.1    59.2  20.7
2024 01 01    18 13.30   +26 29.6    1.137    0.908    50.1    56.1  20.9
2024 01 06    18 07.69   +26 09.8    1.185    0.945    50.7    53.6  21.2
2024 01 11    18 02.54   +25 48.7    1.223    0.989    51.9    51.5  21.4


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

                         (C) Copyright 2023 CBAT
2023 November 11                 (CBET 5316)              Daniel W. E. Green