[Iaude] CBET 4777: COMET C/2020 H7
quai at eps.harvard.edu
quai at eps.harvard.edu
Thu May 21 18:56:45 EDT 2020
Electronic Telegram No. 4777
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 H7 (LEMMON)
An apparently asteroidal object discovered on images taken by G. J.
Leonard with the Mount Lemmon Survey 1.5-m reflector on Apr. 29.4 UT
(discovery observations tabulated below) has been found to show cometary
appearance by observers elsewhere after the object was posted on the Minor
Planet Center's PCCP webpage.
2020 UT R.A. (2000) Decl. Mag. Observer
Apr. 29.42332 17 40 11.31 +27 32 32.7 20.6 Leonard
29.42852 17 40 10.87 +27 32 36.9 20.7 "
29.43376 17 40 10.38 +27 32 40.7 20.7 "
29.43900 17 40 09.92 +27 32 44.9 20.6 "
29.47407 17 40 06.79 +27 33 12.2 20.6 "
29.47764 17 40 06.48 +27 33 14.9 "
29.47919 17 40 06.33 +27 33 15.5 "
H. Sato, Tokyo, Japan, writes that fourteen stacked 60-s exposures taken
remotely with a 0.61-m f/6.5 astrograph located at the Sierra Remote
Observatory near Auberry, CA, USA, on May 2.5 UT show a stellar appearance;
the magnitude was 20.8 as measured within a circular aperture of radius 3".7.
Twenty-five stacked 120-s unfiltered exposures taken by E. Bryssinck,
Kruibeke, Belgium, with a 0.4-m f/3.8 reflector, during May 11.94-11.97 shows
a diffuse, elongated coma of size 8" x 11", oriented north-south (p.a. about
183 deg); the magnitude was 20.0 in an aperture of radius 5". Images taken
by D. D. Balam and D. W. E. Green on May 18.34 with the 1.82-m Plaskett
telescope (+ SDSS g' filter) of the National Research Council of Canada show
a small coma (full-width-at-half-maximum 4".2, vs. 2".5 for nearby stars)
that is elongated toward p.a. about 100 degrees; additional exposures taken
on May 19.3 show the comet to be clearly extended compared to nearby stars.
The available astrometry appear on MPEC 2020-K107. The following
preliminary parabolic orbital elements by S. Nakano, Sumoto, Japan, are from
130 observations spanning Apr. 29-May 19 (mean residual 0".4).
T = 2020 June 2.8617 TT Peri. = 82.6623
Node = 323.5151 2000.0
q = 4.420622 AU Incl. = 135.9203
The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 11.5 and 2.5n = 8 for the
magnitudes.
Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag.
2020 04 21 17 51.58 +25 38.4 3.967 4.435 111.5 12.2 19.7
2020 04 26 17 45.05 +26 47.0 3.912 4.431 114.9 11.9 19.6
2020 05 01 17 37.84 +27 53.0 3.865 4.429 118.1 11.6 19.6
2020 05 06 17 29.98 +28 55.5 3.825 4.427 120.8 11.3 19.6
2020 05 11 17 21.52 +29 53.3 3.793 4.425 123.0 11.0 19.6
2020 05 16 17 12.51 +30 45.5 3.770 4.423 124.6 10.8 19.5
2020 05 21 17 03.05 +31 31.0 3.756 4.422 125.6 10.7 19.5
2020 05 26 16 53.25 +32 09.1 3.751 4.421 125.8 10.7 19.5
2020 05 31 16 43.25 +32 39.0 3.756 4.421 125.4 10.8 19.5
2020 06 05 16 33.18 +33 00.6 3.769 4.421 124.3 10.9 19.5
2020 06 10 16 23.17 +33 13.7 3.792 4.421 122.5 11.2 19.6
2020 06 15 16 13.38 +33 18.4 3.823 4.422 120.2 11.5 19.6
2020 06 20 16 03.91 +33 15.3 3.862 4.423 117.4 11.8 19.6
2020 06 25 15 54.89 +33 04.8 3.908 4.424 114.3 12.1 19.6
2020 06 30 15 46.40 +32 47.8 3.961 4.426 110.9 12.4 19.7
2020 07 05 15 38.51 +32 25.0 4.020 4.428 107.2 12.7 19.7
2020 07 10 15 31.25 +31 57.5 4.084 4.431 103.4 12.9 19.7
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2020 CBAT
2020 May 21 (CBET 4777) Daniel W. E. Green
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