[Iaude] CBET 4838: COMET C/2020 M3

[quai at eps.harvard.edu]

                                                  Electronic Telegram No. 4838
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/2020 M3 (ATLAS)
     K. Kadota (Ageo, Japan, 0.25-m f/5 reflector) and K. Yoshimoto
(Yamaguchi, Japan; remotely using a 0.50-m f/6.8 reflector at Siding Spring,
NSW) have reported new astrometry (in addition to that published yesterday on
MPEC 2020-Q175), as tabulated below.

     2020 UT             R.A. (2000) Decl.       Mag.   Observer
     Aug. 13.77223    2 07 04.84   -35 35 11.4   15.8   Kadota
          13.78559    2 07 07.09   -35 35 16.0            "
          24.71380    2 38 30.12   -36 16 31.3          Yoshimoto
          24.72022    2 38 31.20   -36 16 32.2   12.8     "

Yoshimoto notes that eight stacked 60-s exposures show the presence of a
very diffuse coma of size 3'.6 and a tail 1'.5 long in p.a. 250 deg.
     S. Nakano (CBAT) provides the following revised orbital elements
(cf. CBET 4808) from 105 observations spanning 2020 June 27-Aug. 24,
indicating that this is a periodic comet with an intermediate period.

     T = 2020 Oct. 25.62095 TT        Peri. = 328.44595
     e = 0.9525863                    Node  =  71.24731 2000.0
     q = 1.2682163 AU                 Incl. =  23.47210
       a = 26.7478689 AU   n = 0.00712476   P = 138.34 years

The following ephemeris by the undersigned from the above elements uses
photometric power-law parameters H = 14.0 and 2.5n = 10 for the magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2020 08 19    02 21.98   -35 58.0    0.880    1.606   116.0    34.5  15.8
2020 08 24    02 36.42   -36 14.6    0.831    1.564   115.8    35.6  15.5
2020 08 29    02 50.97   -36 24.4    0.786    1.523   115.5    36.7  15.3
2020 09 03    03 05.54   -36 25.5    0.743    1.485   115.2    37.9  15.1
2020 09 08    03 20.02   -36 16.1    0.702    1.449   114.8    39.1  14.8
2020 09 13    03 34.29   -35 54.2    0.663    1.416   114.4    40.3  14.6
2020 09 18    03 48.21   -35 17.7    0.627    1.385   114.2    41.5  14.4
2020 09 23    04 01.65   -34 24.1    0.592    1.357   114.1    42.4  14.2
2020 09 28    04 14.49   -33 10.5    0.558    1.333   114.3    43.2  14.0
2020 10 03    04 26.63   -31 34.1    0.526    1.312   114.9    43.8  13.8
2020 10 08    04 37.95   -29 31.8    0.496    1.295   115.9    44.0  13.6
2020 10 13    04 48.31   -27 00.1    0.468    1.282   117.4    43.7  13.4
2020 10 18    04 57.61   -23 54.8    0.441    1.273   119.6    42.9  13.3
2020 10 23    05 05.74   -20 11.8    0.417    1.269   122.6    41.4  13.1
2020 10 28    05 12.65   -15 48.0    0.396    1.269   126.4    39.1  13.0
2020 11 02    05 18.26   -10 42.3    0.378    1.273   131.0    36.0  12.9
2020 11 07    05 22.51   -04 57.3    0.366    1.282   136.5    32.1  12.9
2020 11 12    05 25.37   +01 19.5    0.359    1.294   142.8    27.5  12.9
2020 11 17    05 26.83   +07 54.6    0.359    1.311   149.5    22.5  13.0
2020 11 22    05 27.02   +14 30.3    0.367    1.332   156.4    17.3  13.1
2020 11 27    05 26.13   +20 47.4    0.382    1.356   162.7    12.5  13.2
2020 12 02    05 24.40   +26 30.2    0.404    1.383   167.5     8.9  13.4
2020 12 07    05 22.11   +31 28.7    0.434    1.414   169.3     7.4  13.7
2020 12 12    05 19.59   +35 39.4    0.470    1.447   167.4     8.5  14.0
2020 12 17    05 17.21   +39 03.7    0.513    1.483   163.6    10.8  14.3


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

                         (C) Copyright 2020 CBAT
2020 August 25                   (CBET 4838)              Daniel W. E. Green