[Iaude] CBET 4784: COMET C/2019 K6

quai at eps.harvard.edu quai at eps.harvard.edu
Mon May 25 21:49:49 EDT 2020


                                                  Electronic Telegram No. 4784
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/2019 K6 (PANSTARRS)
     An apparently asteroidal object discovery with the Pan-STARRS2 1.8-m
Ritchey-Chretien reflector at Haleakala on 2019 May 31.6 UT has been found
to show cometary appearance by CCD astrometrists elsewhere.  The comet was
given the designation A/2019 K6 when announced on MPEC 2019-N10; the discovery
observations are tabulated below along with pre-discovery Pan-STARRS1
observations also found on 2019 May 7.5.

     2019 UT             R.A. (2000) Decl.       Mag.
     May   7.46071   18 01 14.06   +16 07 39.0   21.1
           7.47302   18 01 13.28   +16 07 41.0   21.3
           7.48531   18 01 12.51   +16 07 42.8   20.9
          31.55619   17 31 08.36   +16 32 19.8   20.6
          31.55619   17 31 08.37   +16 32 19.9   21.1
          31.56847   17 31 07.32   +16 32 19.2   20.8
          31.56847   17 31 07.43   +16 32 19.0   24.2
          31.58080   17 31 06.27   +16 32 18.7   20.9
          31.58080   17 31 06.26   +16 32 18.5   20.9

H. Sato, Tokyo, Japan, reports that CCD images taken with a 0.51-m f/6.8
astrograph at Siding Spring, NSW, Australia, on 2020 Mar. 20.78 UT show a
strongly condensed coma 12" in diameter; the magnitude was 18.2 as measured
within a circular aperture of radius 6".5.  Four stacked 30-s exposures
taken on 2020 Apr. 24.4 by K. Wierzchos with the Mount Lemmon 1.5-m
reflector show a short, diffuse tail.  E. Guido, Castellammare di Stabia,
Italy, writes that twelve stacked 60-s unfiltered exposures taken remotely
on 2020 Apr. 25.5 with an iTelescope 0.50-m f/6.8 astrograph at Siding Spring
show a compact coma about 5" in diameter and a tail 20" long in p.a. 55
degrees; the magnitude was measured to be 18.5-18.9.
     Upon a request for additional information by the Central Bureau, R.
Weryk, Institute for Astronomy, University of Hawaii, writes that 45-s w-band
Pan-STARRS1 images taken during the past month show this object to be clearly
a comet.  On 2020 Apr. 26, there was a tail > 40" long in p.a. 60 degrees; on
Apr. 28, the images show a tail > 30" long in p.a. 60 deg; on May 15, there
was a tail > 30" long in p.a. 70 deg; and on May 19, there was a tail > 40"
long in p.a. 70 deg.  The coma on the four nights was 2".9, 2".6, 1".6, and
2".1 in size (full-width-at-half-maximum) with seeing being 1".7, 1".4, 1".0,
and 1".5, respectively.
     The following orbital elements by S. Nakano, Sumoto, Japan, are from
278 observations spanning 2019 May 7-2020 Apr. 28 (mean residual 0".50).  The
corresponding original and future values of 1/a are +0.001026 and +0.001213
AU**-1, respectively; the comet passed 2.60 AU from Jupiter on 2019 Aug. 6 UT.

                    Epoch = 2020 May  31.0 TT
     T = 2020 May  20.17397 TT        Peri. = 187.61571
     e = 0.9973879                    Node  =  42.94005 2000.0
     q = 3.9286413 AU                 Incl. = 132.37332

The following ephemeris by the undersigned, from the above orbital elements,
uses photometric power-law parameters H = 11.0 and 2.5n = 8 for the magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2020 04 21    14 46.38   -18 32.0    2.954    3.937   166.1     3.5  18.1
2020 04 26    14 35.45   -18 39.0    2.934    3.934   172.8     1.8  18.1
2020 05 01    14 24.35   -18 42.8    2.927    3.932   175.7     1.1  18.1
2020 05 06    14 13.26   -18 43.6    2.932    3.931   170.3     2.5  18.1
2020 05 11    14 02.36   -18 41.8    2.951    3.929   163.4     4.2  18.1
2020 05 16    13 51.82   -18 37.7    2.982    3.929   156.3     5.9  18.1
2020 05 21    13 41.76   -18 32.0    3.024    3.929   149.3     7.6  18.2
2020 05 26    13 32.31   -18 25.1    3.077    3.929   142.4     9.0  18.2
2020 05 31    13 23.55   -18 17.8    3.140    3.930   135.7    10.4  18.2
2020 06 05    13 15.52   -18 10.7    3.211    3.931   129.1    11.5  18.3
2020 06 10    13 08.26   -18 04.3    3.289    3.933   122.8    12.5  18.3
2020 06 15    13 01.77   -17 58.9    3.374    3.935   116.6    13.3  18.4
2020 06 20    12 56.02   -17 55.0    3.463    3.938   110.6    14.0  18.5
2020 06 25    12 51.00   -17 52.8    3.557    3.941   104.8    14.4  18.5
2020 06 30    12 46.65   -17 52.5    3.653    3.945    99.2    14.7  18.6
2020 07 05    12 42.95   -17 54.3    3.750    3.949    93.7    14.9  18.6
2020 07 10    12 39.84   -17 58.2    3.849    3.953    88.4    14.9  18.7
2020 07 15    12 37.27   -18 04.3    3.947    3.958    83.2    14.8  18.8
2020 07 20    12 35.20   -18 12.4    4.045    3.964    78.2    14.5  18.8
2020 07 25    12 33.58   -18 22.7    4.141    3.970    73.3    14.2  18.9
2020 07 30    12 32.37   -18 35.1    4.234    3.976    68.5    13.7  18.9
2020 08 04    12 31.53   -18 49.5    4.324    3.983    63.9    13.2  19.0
2020 08 09    12 31.02   -19 05.9    4.411    3.990    59.3    12.6  19.0
2020 08 14    12 30.80   -19 24.1    4.495    3.998    54.9    12.0  19.1
2020 08 19    12 30.85   -19 44.2    4.573    4.006    50.5    11.2  19.1
2020 08 24    12 31.12   -20 06.1    4.647    4.015    46.3    10.5  19.2
2020 08 29    12 31.59   -20 29.7    4.715    4.024    42.2     9.7  19.2
2020 09 03    12 32.24   -20 55.0    4.778    4.034    38.2     8.9  19.2
2020 09 08    12 33.02   -21 21.8    4.835    4.044    34.4     8.1  19.3
2020 09 13    12 33.93   -21 50.2    4.886    4.054    30.7     7.3  19.3
2020 09 18    12 34.94   -22 20.1    4.931    4.065    27.4     6.5  19.3
2020 09 23    12 36.02   -22 51.6    4.969    4.076    24.4     5.8  19.4
2020 09 28    12 37.14   -23 24.4    5.001    4.088    21.9     5.2  19.4
2020 10 03    12 38.29   -23 58.6    5.026    4.100    20.0     4.8  19.4
2020 10 08    12 39.45   -24 34.2    5.044    4.112    19.1     4.6  19.4
2020 10 13    12 40.58   -25 11.2    5.055    4.125    19.1     4.5  19.4
2020 10 18    12 41.68   -25 49.5    5.060    4.138    20.1     4.8  19.5
2020 10 23    12 42.70   -26 29.1    5.058    4.152    22.0     5.2  19.5
2020 10 28    12 43.63   -27 09.9    5.049    4.166    24.6     5.7  19.5
2020 11 02    12 44.44   -27 52.0    5.034    4.181    27.6     6.3  19.5
2020 11 07    12 45.10   -28 35.3    5.013    4.195    31.1     7.0  19.5
2020 11 12    12 45.58   -29 19.8    4.985    4.210    34.8     7.7  19.5
2020 11 17    12 45.86   -30 05.4    4.952    4.226    38.7     8.4  19.5
2020 11 22    12 45.89   -30 52.0    4.914    4.242    42.8     9.1  19.5
2020 11 27    12 45.64   -31 39.7    4.870    4.258    46.9     9.7  19.5
2020 12 02    12 45.07   -32 28.2    4.822    4.275    51.2    10.4  19.5
2020 12 07    12 44.14   -33 17.5    4.770    4.291    55.6    10.9  19.5
2020 12 12    12 42.82   -34 07.4    4.714    4.309    60.1    11.4  19.4
2020 12 17    12 41.04   -34 57.7    4.655    4.326    64.7    11.9  19.4


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

                         (C) Copyright 2020 CBAT
2020 May 25                      (CBET 4784)              Daniel W. E. Green



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