[Iaude] CBET 4834: COMET 141P/MACHHOLZ
quai at eps.harvard.edu
quai at eps.harvard.edu
Wed Aug 19 13:52:52 EDT 2020
Electronic Telegram No. 4834
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 141P/MACHHOLZ
An apparently asteroidal object reported as an apparent new minor
planet from images obtained with the Pan-STARRS2 1.8-m Ritchey-Chretien
reflector at Haleakala (discovery observations tabulated below), and posted
on the Minor Planet Center's NEOCP webpage, has been found by P. Veres and
D. Bell (MPC) to have motion similar to that of comet 141P (which had not
been seen since 2015) after follow-up astrometry was reported. R. Weryk
notes that the Pan-STARRS2 images do not appear cometary. R. Holmes,
Ashmore, IL, USA, reports that the object appears stellar in 2".6 seeing
on images taken with a 1.3-m f/4.0 astrograph on Aug. 15.1 UT. M. Micheli
writes that thirty-eight stacked exposures (corresponding to a total
integration of 57 min) taken by E. Kuusela with the 1.0-m f/4.4 reflector
of the ESA Optical Ground Station, Tenerife, show the comet to be completely
stellar in 2".0 seeing; he was unable to find any additional fragments in
the images but adds that the field is heavily crowded with stars.
2020 UT R.A. (2000) Decl. Mag. Observer
Aug. 13.26514 16 56 13.18 - 8 29 51.4 21.6 Pan-STARRS2
13.27539 16 56 12.89 - 8 29 51.3 21.7 "
13.28565 16 56 12.58 - 8 29 51.1 21.5 "
15.08524 16 55 29.86 - 8 29 26.2 21.5 Holmes
15.09133 16 55 29.71 - 8 29 25.9 22.0 "
15.10046 16 55 29.49 - 8 29 26.0 22.1 "
16.87731 16 54 55.30 - 8 29 22.9 21.5 Kuusela
16.89106 16 54 55.05 - 8 29 23.2 21.6 "
16.90536 16 54 54.74 - 8 29 23.2 21.6 "
Shortly after this comet was first discovered in 1994 (cf. IAUC 6053),
it was found to have a nearby (about 48' distant) diffuse companion nearly as
bright as the primary component (cf. IAUC 6066), followed by the discovery of
three additional fainter components (cf. IAUCs 6071, 6071); the original
component remained the brightest and was called component A (cf. IAUC 6081).
Component D, meanwhile, split into two fragments, and became nearly as bright
as component A (cf. IAUCs 6082, 6090). Two additional components were
reported also in 1994 (cf. MPEC 2017-R12), leading to the use of component
letters A-G at that apparition.
After the comet's recovery in 1999 (cf. IAUC 7231), linkages of what was
presumed to be component A to the 1994 observations were not possible without
resorting to allowance for non-gravitational forces. As the comet approached
perihelion in late 1999, a second component (only) was detected and presumed
to be component D from 1994 (cf. IAUC 7299), and the two components remained
within a couple of magnitudes of each other in brightness for weeks (cf. IAUC
7334). Only a single component of the comet was recovered in 2005, and it
was presumed to be component A (cf. IAUC 8495).
Note that the comet was missed at its 2010 return. The comet was
observed extensively at its 2015 return, starting on 2015 May 24 (cf. MPEC
2015-K133). Beginning on 2015 Aug. 19, another component was widely
observed and designated H by G. V. Willams, who wrote (MPEC 2015-R12) that
the 2015 astrometry of component H "precludes an unambiguous linkage to a
known fragment. Computations by both [myself] and S. Nakano suggest that
[component H] can be linked to either fragment C or fragment D (equally
well), or to fragment B (less satisfactorily). Fragment D was observed in
both 1994 and 1999, while fragment B faded rapidly over the course of a week
in Nov. 1994. In no case is the linkage to a known fragment satisfactory."
S. Nakano's previous orbit for component A from 258 observations
spanning 2000-2015 (mean residual 0".9) yielded non-gravitational parameters
A1 = -0.12 and A2 = +0.0274 (cf. NK 3435 and the ICQ's 2020 Comet Handbook),
and the 2020 observations suggest a correction Delta(T) = +0.025 day; the
residuals for the 2020 astrometry are -18" in R.A. and -9" in Decl. from
that prediction. The following new orbital elements by Nakano assume that
the recovery in 2020 is of component A and use 266 observations spanning
2005-2020 (mean residual 0".9), with non-gravitational parameters A1 = +0.37
and A2 = +0.0304. The comet passed 0.93 AU from Jupiter on 2017 Oct. 13 UT
and will pass 0.53 AU from the earth on 2021 Jan. 19. Nakano adds that the
prediction for component H at this return would be T = 2020 Dec. 14.6 TT.
Epoch = 2005 Mar. 11.0 TT
T = 2005 Feb. 28.24835 TT Peri. = 149.27843
e = 0.7501302 Node = 246.16572 2000.0
q = 0.7528003 AU Incl. = 12.79585
a = 3.0127704 AU n = 0.18847555 P = 5.23 years
Epoch = 2010 June 13.0 TT
T = 2010 May 24.52279 TT Peri. = 149.36131
e = 0.7489010 Node = 246.08989 2000.0
q = 0.7577396 AU Incl. = 12.80307
a = 3.0176926 AU n = 0.18801460 P = 5.24 years
Epoch = 2015 Aug. 6.0 TT
T = 2015 Aug. 25.02115 TT Peri. = 149.47494
e = 0.7481753 Node = 246.01793 2000.0
q = 0.7608722 AU Incl. = 12.80987
a = 3.0214359 AU n = 0.18766531 P = 5.25 years
Epoch = 2020 Dec. 17.0 TT
T = 2020 Dec. 16.26997 TT Peri. = 153.54399
e = 0.7356668 Node = 241.84951 2000.0
q = 0.8079340 AU Incl. = 13.94456
a = 3.0564980 AU n = 0.18444543 P = 5.34 years
Epoch = 2026 Apr. 30.0 TT
T = 2026 Apr. 23.13453 TT Peri. = 153.64837
e = 0.7358060 Node = 241.77030 2000.0
q = 0.8074757 AU Incl. = 13.96016
a = 3.0563737 AU n = 0.18445668 P = 5.34 years
Epoch = 2031 Aug. 2.0 TT
T = 2031 Aug. 20.05162 TT Peri. = 154.81822
e = 0.7437472 Node = 240.99513 2000.0
q = 0.7742034 AU Incl. = 14.52203
a = 3.0212489 AU n = 0.18768273 P = 5.25 years
The following ephemeris by the undersigned from the above elements uses
photometric power-law parameters H = 12.0 and 2.5n = 30.0 for the magnitudes.
Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag.
2020 08 19 16 54.41 -08 29.8 1.288 1.851 106.6 31.6 20.6
2020 08 29 16 54.53 -08 38.6 1.306 1.749 97.3 34.9 19.9
2020 09 08 16 58.66 -08 55.8 1.320 1.645 88.9 37.7 19.1
2020 09 18 17 06.63 -09 18.5 1.326 1.540 81.4 40.2 18.2
2020 09 28 17 18.29 -09 43.3 1.320 1.433 74.8 42.4 17.3
2020 10 08 17 33.52 -10 07.0 1.301 1.327 69.0 44.7 16.3
2020 10 18 17 52.34 -10 26.6 1.266 1.221 64.0 47.2 15.1
2020 10 28 18 14.86 -10 39.1 1.215 1.118 59.8 50.2 13.9
2020 11 07 18 41.27 -10 41.9 1.147 1.022 56.5 54.0 12.6
2020 11 17 19 11.91 -10 33.5 1.062 0.936 54.1 58.9 11.3
2020 11 27 19 47.29 -10 14.0 0.964 0.867 52.7 65.0 10.1
2020 12 07 20 28.13 -09 46.1 0.857 0.822 52.4 71.8 9.1
2020 12 17 21 15.72 -09 14.2 0.748 0.808 53.5 78.3 8.6
2020 12 27 22 12.07 -08 38.9 0.650 0.827 56.5 82.6 8.6
2021 01 06 23 19.11 -07 49.9 0.574 0.875 62.0 82.6 9.1
2021 01 16 00 35.84 -06 27.2 0.536 0.947 70.2 77.7 9.9
2021 01 26 01 55.13 -04 22.4 0.544 1.035 79.6 69.3 11.1
2021 02 05 03 07.10 -01 57.0 0.598 1.133 87.7 60.4 12.5
2021 02 15 04 06.75 +00 20.1 0.690 1.236 93.2 52.9 14.0
2021 02 25 04 54.71 +02 14.0 0.810 1.342 95.9 47.2 15.4
2021 03 07 05 33.72 +03 42.4 0.952 1.449 96.3 42.9 16.7
2021 03 17 06 06.41 +04 47.8 1.111 1.555 95.1 39.6 18.0
2021 03 27 06 34.71 +05 33.1 1.282 1.660 92.7 36.9 19.1
2021 04 06 06 59.87 +06 00.9 1.462 1.764 89.4 34.6 20.2
2021 04 16 07 22.77 +06 13.6 1.651 1.866 85.6 32.4 21.2
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2020 CBAT
2020 August 19 (CBET 4834) Daniel W. E. Green
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