Orbital Computation
Kreutz Group Comet
SOHO-2018
in
HI1A & HI1B Images
The Kreutz group sungrazer is
discovered by Michal Kusiak from Poland on 2010 Feb 01 in realtime C3 images.
 |
Comet SOHO-2018 in HI1a
Images
Animation from 2011/01/31 00:09 UTC -
2010/02/01 00:49 UTC
each sequence 40 min apart;
1.5x resized and cropped;
processed by M.-T. Hui;
Courtesy of STEREO/SECCHI |
 |
Comet SOHO-2018 in HI1b
Images
Animation from 2011/01/31 04:09 UTC -
2010/02/01 05:29 UTC
each sequence 40 min apart;
original size and cropped;
processed by M.-T. Hui;
Courtesy of STEREO/SECCHI |
I managed to do astrometry of this comet in
HI1A data. Here comes my result. Note that the spacecraft vectors for
corresponding observations have been added; the values were given by JPL
Horizons.
Observations of SOHO-2018: computed with Astrometrica
- NET UCAC-2
SMK2018 4S2011 01 31.26364 13 47 28.98 -18 12
55.7
C50
SMK2018 4s2011 01 31.26364 2 +1.46439181
-0.10170756 -0.03898109 C50
SMK2018 4S2011 01 31.29098 02 47 28.40 +10 27
20.9
C49
SMK2018 4s2011 01 31.29098 2 -0.12185942
-1.21616482 -0.52712779 C49
SMK2018 4S2011 01 31.31876 02 47 17.80 +10 29
37.7
C49
SMK2018 4s2011 01 31.31876 2 -0.12119380
-1.21623123 -0.52715541 C49
SMK2018 4S2011 01 31.34654 02 47 07.60 +10 31
47.0
C49
SMK2018 4s2011 01 31.34654 2 -0.12052814
-1.21629734 -0.52718290 C49
SMK2018 4S2011 01 31.34698 13 48 56.17 -18 08
48.2
C50
SMK2018 4s2011 01 31.34698 2 +1.46458863
-0.09985414 -0.03817402 C50
SMK2018 4S2011 01 31.37432 02 46 59.67 +10 33
35.8
C49
SMK2018 4s2011 01 31.37432 2 -0.11986244
-1.21636315 -0.52721026 C49
SMK2018 4S2011 01 31.40209 02 46 51.14 +10 35
07.9
C49
SMK2018 4s2011 01 31.40209 2 -0.11919670
-1.21642866 -0.52723749 C49
SMK2018 4S2011 01 31.42987 02 46 42.92 +10 37
38.0
C49
SMK2018 4s2011 01 31.42987 2 -0.11853091
-1.21649387 -0.52726459 C49
SMK2018 4S2011 01 31.43031 13 50 23.93 -18 04
19.3
C50
SMK2018 4s2011 01 31.43031 2 +1.46478254
-0.09800032 -0.03736679 C50
SMK2018 4S2011 01 31.45765 02 46 30.65 +10 39
40.9
C49
SMK2018 4s2011 01 31.45765 2 -0.11786508
-1.21655877 -0.52729156 C49
SMK2018 4S2011 01 31.45809 13 50 50.14 -18 03
13.8
C50
SMK2018 4s2011 01 31.45809 2 +1.46484654
-0.09738229 -0.03709768 C50
SMK2018 4S2011 01 31.48543 02 46 23.20 +10 41
38.3
C49
SMK2018 4s2011 01 31.48543 2 -0.11719922
-1.21662338 -0.52731840 C49
SMK2018 4S2011 01 31.51321 02 46 12.81 +10 43
59.6
C49
SMK2018 4s2011 01 31.51321 2 -0.11653330
-1.21668768 -0.52734511 C49
SMK2018 4S2011 01 31.51364 13 51 46.57 -18 00
28.7
C50
SMK2018 4s2011 01 31.51364 2 +1.46497357
-0.09614609 -0.03655939 C50
SMK2018 4S2011 01 31.54098 02 46 02.91 +10 45
44.4
C49
SMK2018 4s2011 01 31.54098 2 -0.11586735
-1.21675168 -0.52737169 C49
SMK2018 4S2011 01 31.54142 13 52 13.52 -17 58
46.0
C50
SMK2018 4s2011 01 31.54142 2 +1.46503660
-0.09552793 -0.03629022 C50
SMK2018 4S2011 01 31.56876 02 45 51.84 +10 47
59.2
C49
SMK2018 4s2011 01 31.56876 2 -0.11520136
-1.21681538 -0.52739813 C49
SMK2018 4S2011 01 31.56920 13 52 41.38 -17 58
10.7
C50
SMK2018 4s2011 01 31.56920 2 +1.46509931
-0.09490972 -0.03602104 C50
SMK2018 4S2011 01 31.59698 13 53 10.34 -17 56
23.2
C50
SMK2018 4s2011 01 31.59698 2 +1.46516169
-0.09429147 -0.03575183 C50
SMK2018 4S2011 01 31.62432 02 45 36.21 +10 52
14.3
C49
SMK2018 4s2011 01 31.62432 2 -0.11386925
-1.21694188 -0.52745064 C49
SMK2018 4S2011 01 31.62475 13 53 41.73 -17 55
12.4
C50
SMK2018 4s2011 01 31.62475 2 +1.46522376
-0.09367318 -0.03548261 C50
SMK2018 4S2011 01 31.65209 02 45 26.41 +10 53
51.8
C49
SMK2018 4s2011 01 31.65209 2 -0.11320314
-1.21700468 -0.52747669 C49
SMK2018 4S2011 01 31.68031 13 54 34.15 -17 52
32.3
C50
SMK2018 4s2011 01 31.68031 2 +1.46534692
-0.09243646 -0.03494411 C50
SMK2018 4S2011 01 31.70765 02 45 07.93 +10 58
01.0
C49
SMK2018 4s2011 01 31.70765 2 -0.11187079
-1.21712937 -0.52752841 C49
SMK2018 4S2011 01 31.70809 13 55 04.33 -17 50
50.7
C50
SMK2018 4s2011 01 31.70809 2 +1.46540802
-0.09181803 -0.03467483 C50
SMK2018 4S2011 01 31.73587 13 55 33.58 -17 49
33.0
C50
SMK2018 4s2011 01 31.73587 2 +1.46546880
-0.09119956 -0.03440554 C50
SMK2018 4S2011 01 31.76364 13 56 02.75 -17 47
50.6
C50
SMK2018 4s2011 01 31.76364 2 +1.46552925
-0.09058105 -0.03413623 C50
SMK2018 4S2011 01 31.79098 02 44 35.54 +11 05
07.4
C49
SMK2018 4s2011 01 31.79098 2 -0.10987196
-1.21731415 -0.52760501 C49
SMK2018 4S2011 01 31.79142 13 56 32.69 -17 46
31.5
C50
SMK2018 4s2011 01 31.79142 2 +1.46558938
-0.08996250 -0.03386690 C50
SMK2018 4S2011 01 31.81876 02 44 24.32 +11 07
19.0
C49
SMK2018 4s2011 01 31.81876 2 -0.10920560
-1.21737514 -0.52763028 C49
SMK2018 4S2011 01 31.81920 13 57 01.89 -17 44
48.5
C50
SMK2018 4s2011 01 31.81920 2 +1.46564919
-0.08934390 -0.03359755 C50
SMK2018 4S2011 01 31.84654 02 44 12.10 +11 09
43.5
C49
SMK2018 4s2011 01 31.84654 2 -0.10853921
-1.21743583 -0.52765543 C49
SMK2018 4S2011 01 31.84698 13 57 29.15 -17 43
30.6
C50
SMK2018 4s2011 01 31.84698 2 +1.46570868
-0.08872526 -0.03332819 C50
SMK2018 4S2011 01 31.87432 02 44 05.67 +11 11
58.4
C49
SMK2018 4s2011 01 31.87432 2 -0.10787278
-1.21749621 -0.52768044 C49
SMK2018 4S2011 01 31.90209 02 43 52.61 +11 14
22.1
C49
SMK2018 4s2011 01 31.90209 2 -0.10720630
-1.21755630 -0.52770532 C49
SMK2018 4S2011 01 31.90253 13 58 28.02 -17 40
45.4
C50
SMK2018 4s2011 01 31.90253 2 +1.46582669
-0.08748785 -0.03278941 C50
SMK2018 4S2011 01 31.92987 02 43 42.71 +11 16
36.6
C49
SMK2018 4s2011 01 31.92987 2 -0.10653979
-1.21761608 -0.52773007 C49
SMK2018 4S2011 01 31.95765 02 43 31.51 +11 19
03.2
C49
SMK2018 4s2011 01 31.95765 2 -0.10587324
-1.21767557 -0.52775469 C49
SMK2018 4S2011 01 31.95809 13 59 26.06 -17 37
30.7
C50
SMK2018 4s2011 01 31.95809 2 +1.46594340
-0.08625028 -0.03225056 C50
SMK2018 4S2011 01 31.98543 02 43 18.93 +11 21
52.3
C49
SMK2018 4s2011 01 31.98543 2 -0.10520665
-1.21773475 -0.52777917 C49
SMK2018 4S2011 01 31.98586 13 59 54.53 -17 35
52.4
C50
SMK2018 4s2011 01 31.98586 2 +1.46600128
-0.08563143 -0.03198111 C50
SMK2018 4S2011 02 01.01321 02 43 11.02 +11 24
11.1
C49
SMK2018 4s2011 02 01.01321 2 -0.10454002
-1.21779363 -0.52780353 C49
SMK2018 4S2011 02 01.04142 14 00 54.82 -17 32
41.6
C50
SMK2018 4s2011 02 01.04142 2 +1.46611606
-0.08439360 -0.03144217 C50
SMK2018 4S2011 02 01.06920 14 01 23.54 -17 30
54.2
C50
SMK2018 4s2011 02 01.06920 2 +1.46617297
-0.08377463 -0.03117266 C50
SMK2018 4S2011 02 01.09698 14 01 53.16 -17 29
10.7
C50
SMK2018 4s2011 02 01.09698 2 +1.46622955
-0.08315561 -0.03090315 C50
SMK2018 4S2011 02 01.12475 14 02 23.30 -17 27
45.7
C50
SMK2018 4s2011 02 01.12475 2 +1.46628581
-0.08253655 -0.03063361 C50
SMK2018 4S2011 02 01.18031 14 03 25.97 -17 23
49.7
C50
SMK2018 4s2011 02 01.18031 2 +1.46639737
-0.08129832 -0.03009450 C50
SMK2018 4S2011 02 01.20809 14 03 56.83 -17 22
20.2
C50
SMK2018 4s2011 02 01.20809 2 +1.46645266
-0.08067914 -0.02982491 C50
Station data:
C49 STEREO-A. SECCHI HI1 imager. Comet detection by M. Kusiak, measurements
by M.-T. Hui, reductions by M.-T. Hui.
C50 STEREO-B. SECCHI HI1 imager. Comet detection by M. Kusiak, measurements
by M.-T. Hui, reductions by M.-T. Hui.
The light curve produced by Comets for Windows
with all the data above is displayed below. Note that the designation SMK2018 =
SOHO 2018. The former designation was the name I used to denote to the comet in
Astrometrica. The red dots represent that magnitudes was measured from HI1A
images, while the blue ones represent measurements from HI1B images, both in R
band, with star catalog USNO-A 2.0 applied.
Calculated lightcurve on the small arc on the
basis of my measurements as observed from the spacecraft: m1 = 19.43 + 5 log d +
11.36 log r, where d is the distance from spacecraft to the comet, and r is the
distance from heliocenter to the comet (both in AU).
I attempted to compute back how bright the
comet is before the detection, so as to see if we will be able to capture some
potential well-behaved Kreutz group members on the ground. The result, however,
surprises me a lot, as shown as follow. Yet I think there is a great uncertainty
as now only one example is taken into consideration and analysed. It may be of
much interest if more sungrazers are analysed. Furthermore, observations of such
a short arc also contribute an unignorable uncertainty, leading to an unreliable
result that should be treated with enormous caution.
Formula: m1 = 11.3 + 5 log d + 0.15 log r,
where d is the distance from geocenter to the comet, and r is again the distance
from heliocenter to the comet (both in AU):
 |
|
 |
|
HI1A |
|
HI1B |
Gauss curve produced by
Astrometrica. The total PSF is using an aperture circle of
3 x
3 pixel around the brightest
pixel. We can see the
computed Gauss curve
in the right and the real pixels
distributing somewhat deviating from the
ideal line. The Fit RMS, which inlays
under the Gauss curve, is the deviation from the ideal line.
By feeding my measurements into FindOrb, I
obtained my best solution with a relatively small RMS.
Orbital elements:
SMK2018
Perihelion 2011 Feb 2.522020 TT; Constraint: e=1
Epoch 2011 Feb 1.0 TT = JDT 2455593.5 Earth MOID: 0.5496
q616933.287km (2000.0) P Q
H 11.3 G 0.15 Peri. 84.54675 0.14973987 -0.98798861
Node 3.84649 -0.96885934 -0.15432051
e 1.0 Incl. 145.32670 0.19720429 -0.00797942
From 48 observations 2011 Jan. 31-Feb. 1 (22.7 hr); RMS error 43.630 arcseconds
Residuals in arcseconds:
110131 C50 34.4- 86.0- 110131 C49 25.8- 31.0+ 110131 C50 2.7+ 21.2-
110131 C49 33.2+ 31.1+ 110131 C50 .75- 47.8- 110131 C49 55.0+ 24.9+
110131 C49 8.4+ 46.9+ 110131 C50 5.9+ 21.9- 110131 C49 20.7+ 32.3+
110131 C49 9.4- 54.6+ 110131 C49 30.9+ 30.2+ 110131 C50 11.6+ 37.4-
110131 C50 11.4+ 60.7- 110131 C50 46.6+ 33.4- 110131 C49 34.7+ 29.5+
110131 C49 7.3+ 41.2+ 110131 C49 31.9+ 1.2- 110131 C49 31.1+ 38.0+
110131 C49 16.1+ 10.5+ 110131 C50 22.6- 40.5- 110131 C50 4.6+ 28.1-
110131 C49 30.8+ 37.1+ 110131 C49 54.4+ 12.3- 110131 C49 8.8+ 67.9+
110131 C50 59.4+ 20.4- 110131 C50 1.8- 23.8- 110131 C50 8.2- 23.9-
110131 C49 13.1- 35.9+ 110131 C50 4.9+ 31.8- 110201 C49 56.9+ 66.6+
110131 C50 30.6+ 32.6- 110131 C50 9.7+ 16.0- 110201 C50 10.8+ 24.5-
110131 C49 15.1+ 28.5+ 110131 C49 29.6+ 17.8+ 110201 C50 1.7- 14.4-
110131 C49 1.3+ 44.3+ 110131 C50 24.6+ 24.4- 110201 C50 2.5- 9.4-
110131 C50 28.0+ 25.1- 110131 C49 17.9+ 15.6+ 110201 C50 3.1+ 23.8-
110131 C49 4.3- 23.0+ 110131 C50 28.0+ 9.8- 110201 C50 44.7+ 9.6+
110131 C50 7.5+ 2.3- 110131 C49 6.9- 25.5+ 110201 C50 56.8+ 3.9-
Click here for an orbit diagram
Copyright
©
Man-To Hui on
2011/02/07
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