[Iaude] CBET 5299: COMET C/2023 S2
quai at eps.harvard.edu
quai at eps.harvard.edu
Mon Oct 2 19:01:38 EDT 2023
Electronic Telegram No. 5299
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 S2 (ATLAS)
P. Veres, Minor Planet Center, informs the Central Bureau that L. Denneau
has reported the discovery of a comet in survey images taken in the course of
the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program
on Sept. 29.0 UT with a 0.5-m f/2 Schmidt reflector at Rio Hurtado, Chile,
noting a diffuse 8".5 coma (cf. MPEC 2023-T5). The discovery observations
are tabulated below.
2023 UT R.A. (2000) Decl. Mag.
Sept.28.98636 15 54 22.83 - 5 53 57.3 15.1
28.98953 15 54 23.53 - 5 53 57.9 15.1
28.99819 15 54 25.48 - 5 53 58.0 15.2
29.00969 15 54 28.06 - 5 53 57.7 15.4
After the comet was posted on the MPC's PCCP webpage, numerous other CCD/CMOS
astrometrists have sent reports of cometary activity to the Central Bureau.
M. Mattiazzo (Swan Hill, Victoria, Australia) writes that stacked 120-s CMOS
exposures using a green filter taken on Sept. 30.0 UT with a 500-mm f/2.8
Takahashi Epsilon 180ED refractor located at Rio Hurtado Valley, Chile, show
a diffuse coma 70" wide of total V magnitude 13.2 (UCAC4 reference
stars). Ten stacked 30-s exposures taken on Oct. 1.4 by Mattiazzo using a
Celestron RASA 0.28-m f/2.2 astrograph at Swan Hill show a diffuse coma 2' in
diameter of UCAC4 V total magnitude 13.0. Twenty-four stacked 10-s CCD
exposures taken remotely on Sept. 30.0 by H. Sato (Bunkyo-ku, Tokyo, Japan)
with a "Deep Sky Chile" 0.51-m f/6.8 astrograph located at Rio Hurtado, Chile,
show a strongly condensed coma 40" in diameter with no tail; the magnitude was
13.8 as measured within a circular aperture of radius 20".2.
E. Guido (Castellammare di Stabia, Italy) writse that twenty stacked
unfiltered 60-s CMOS exposures taken remotely by M. Rocchetto, A. Valvasori,
and himself on Sept. 30.4 UT with a "Telescope Live" 0.10-m f/3.6 refractor
located at Yass, NSW, Australia show a coma about 80" in diameter.
A. Valvasori (Padulle, Italy) adds that eighty stacked unfiltered 30-s CCD
exposures taken by Guido and himself on Oct. 1.75-1.77 with a 0.30-m f/4
reflector at the ALMO Observatory in Italy show a coma about 37" in diameter
of mag 15.3-15.5.
L. Buzzi (Varese, Italy) relates that fifth-two stacked 30-s CCD
exposures taken with an R_c filter on Sept. 30.8 UT by A. Aletti (and measured
by Aletti and F. Bellini) with a 0.36-m f/7.5 reflector at Varese show a
moderately condensed coma 20" wide and a faint, straight tail 15" long toward
p.a. 115 degrees.
J.-F. Soulier finds a coma of size 42" in thirty 30-s unfiltered CCD
exposures taken on Sept. 30.8 UT with a 0.30-m f/3.8 Newtonian reflector at
Maisoncelles, France; the red magnitude was 16.2 in an aperture of radius
6".5. Eighty additional unfiltered 30-s CCD exposures obtained on Oct. 1.8
by Soulier using a 0.25-m f/3.5 Newtonian reflector located at Dauban, France,
show a 45" coma and magnitude 16.4 in an aperture of raidus 6".
T. Prystavski (Lyiv, Ukraine) reports a 2'.5 coma of total mag 12.7 and
no tail on CMOS images obtained on Oct. 1.0 UT with a "Deep Sky Chile" 0.18-m
f/2.8 hyperbolic astrograph located at Rio Hurtado.
J. J. Gonzalez Suarez (observing from Pandorado, Leon, Spain) writes
that he observed this comet visually in a very clear mountain sky on Oct.
2.89 UT with a 0.20-m reflector (when the comet was at altitude 23 degrees),
finding total mag 10.9 and coma diameter 4'.
The following parabolic orbital elements by S. Nakano (Central Bureau)
are from 134 observations spanning 2023 Sept. 28-Oct. 1 (mean residual 0".5).
The comet will pass 0.63 AU from Jupiter on 2024 Oct. 25 UT.
T = 2023 Oct. 15.36672 TT Peri. = 78.09680
Node = 230.49706 2000.0
q = 1.0687808 AU Incl. = 20.49116
The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 12.0 and 2.5n = 8 for the
magnitudes.
Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag.
2023 02 25 13 41.63 -25 21.4 2.779 3.407 121.9 14.3 18.5
2023 03 07 13 40.24 -25 29.9 2.554 3.298 131.7 13.0 18.2
2023 03 17 13 36.65 -25 21.7 2.346 3.187 141.7 11.1 17.9
2023 03 27 13 30.83 -24 52.7 2.160 3.076 151.8 8.8 17.6
2023 04 06 13 23.00 -23 59.4 1.999 2.963 161.1 6.3 17.3
2023 04 16 13 13.67 -22 40.0 1.865 2.850 166.3 4.8 17.0
2023 04 26 13 03.64 -20 55.3 1.761 2.735 162.0 6.5 16.7
2023 05 06 12 53.96 -18 50.5 1.685 2.620 152.3 10.3 16.5
2023 05 16 12 45.66 -16 34.1 1.635 2.504 141.2 14.7 16.3
2023 05 26 12 39.61 -14 16.2 1.608 2.387 129.9 19.0 16.1
2023 06 05 12 36.44 -12 06.6 1.597 2.270 119.1 23.0 15.9
2023 06 15 12 36.42 -10 12.1 1.597 2.152 108.9 26.5 15.7
2023 06 25 12 39.67 -08 36.7 1.602 2.035 99.6 29.5 15.5
2023 07 05 12 46.16 -07 22.0 1.607 1.918 91.1 32.0 15.3
2023 07 15 12 55.78 -06 27.1 1.609 1.801 83.4 34.1 15.1
2023 07 25 13 08.48 -05 50.5 1.604 1.687 76.5 35.8 14.8
2023 08 04 13 24.23 -05 29.8 1.590 1.575 70.5 37.4 14.6
2023 08 14 13 43.05 -05 21.9 1.567 1.467 65.3 38.8 14.3
2023 08 24 14 05.08 -05 23.9 1.533 1.366 61.0 40.3 14.0
2023 09 03 14 30.51 -05 32.1 1.488 1.274 57.6 41.9 13.7
2023 09 13 14 59.58 -05 42.7 1.436 1.194 55.2 43.8 13.4
2023 09 18 15 15.58 -05 47.6 1.408 1.161 54.4 44.8 13.3
2023 09 23 15 32.61 -05 51.5 1.379 1.131 54.0 45.8 13.1
2023 09 28 15 50.69 -05 53.8 1.349 1.107 53.8 46.9 13.0
2023 10 03 16 09.84 -05 54.0 1.320 1.088 53.8 47.9 12.9
2023 10 08 16 30.08 -05 51.5 1.291 1.076 54.2 48.9 12.8
2023 10 13 16 51.41 -05 45.9 1.265 1.070 54.9 49.8 12.7
2023 10 18 17 13.81 -05 36.7 1.242 1.070 55.8 50.4 12.7
2023 10 23 17 37.19 -05 23.2 1.223 1.076 57.0 50.8 12.7
2023 10 28 18 01.45 -05 05.2 1.208 1.089 58.3 50.9 12.7
2023 11 02 18 26.42 -04 42.4 1.200 1.108 59.8 50.7 12.8
2023 11 07 18 51.90 -04 14.8 1.199 1.133 61.4 50.2 12.8
2023 11 12 19 17.64 -03 42.4 1.205 1.162 63.0 49.4 12.9
2023 11 17 19 43.37 -03 05.6 1.220 1.196 64.6 48.3 13.1
2023 11 22 20 08.80 -02 24.9 1.244 1.235 66.0 47.0 13.2
2023 11 27 20 33.65 -01 41.1 1.276 1.276 67.3 45.5 13.4
2023 12 02 20 57.71 -00 54.9 1.317 1.321 68.3 43.9 13.6
2023 12 07 21 20.81 -00 07.1 1.366 1.369 69.0 42.2 13.8
2023 12 12 21 42.84 +00 41.6 1.423 1.418 69.5 40.6 14.0
2023 12 17 22 03.74 +01 30.6 1.487 1.470 69.6 38.9 14.2
2023 12 22 22 23.51 +02 19.5 1.558 1.523 69.5 37.2 14.4
2023 12 27 22 42.16 +03 07.9 1.635 1.578 69.0 35.6 14.7
2024 01 01 22 59.75 +03 55.4 1.718 1.633 68.3 34.0 14.9
2024 01 06 23 16.34 +04 42.0 1.805 1.689 67.3 32.5 15.1
2024 01 11 23 32.03 +05 27.6 1.896 1.746 66.1 31.0 15.3
2024 01 16 23 46.88 +06 12.0 1.991 1.804 64.7 29.5 15.5
2024 01 21 00 00.97 +06 55.3 2.088 1.862 63.1 28.1 15.8
2024 01 26 00 14.38 +07 37.4 2.188 1.920 61.3 26.7 16.0
2024 01 31 00 27.16 +08 18.2 2.290 1.979 59.4 25.4 16.2
2024 02 05 00 39.39 +08 57.7 2.393 2.038 57.3 24.0 16.4
2024 02 10 00 51.12 +09 36.1 2.497 2.096 55.2 22.7 16.6
2024 02 15 01 02.40 +10 13.2 2.602 2.155 52.9 21.4 16.7
2024 02 20 01 13.28 +10 49.0 2.706 2.214 50.6 20.2 16.9
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2023 CBAT
2023 October 2 (CBET 5299) Daniel W. E. Green
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