Solar System
Dynamics &
Planetology
Group 		C/1946 C1 Timmers



data set of C/1946 C1

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General description

Comet C/1946 C1 was discovered on 2 February 1946, that is over two months before perihelion passage, and was last seen on 9 August 1947. Soon a few prediscovery images (January 23, 24, 28 and 29), were found by F.L. Whipple [Kronk, Cometography: Volume 4].

This comet made its closest approach to the Earth on 6 February 1946 (1.016 au), that is four days after its discovery.

Solution given below is based on data span over 1.526 yr in a range of heliocentric distances from 1.973 au through perihelion (1.724 au) to 5.559 au.

Pure gravitational orbit determined from the available positional measurements (485 observations) give 1a-class orbit.

It was possible to determine the non-gravitational orbit for C/1946 C1 where a noticeable decrease of RMS was obtained (from 2.54 arcsec to 2.17 arcsec, see below) and some trends in right ascension and declination were reduced (see figure). This NG-solution give more tight original orbit than pure gravitational solution.

Comet suffered moderate planetary perturbations during its passage through the planetary system that led to a more tight future orbit with semimajor axis less than 3000 au (see future barycentric orbits given below for both models of motion).

More details in Królikowska et al. 2014


Figure caption: Time distribution of positional observations with corresponding heliocentric (red curve) and geocentric (green curve) distance at which they were taken. The horizontal dotted line shows the perihelion distance for a given comet whereas vertical dotted line — the moment of perihelion passage.




Non–gravitational orbit — see below SSDP Cometary Note C1946C1N5-001

SSDP Cometary Note C1946C1A5-001

Comet C/1946 C1 Timmers

number of observations 485
number of residuals 857
data interval 1946 Jan. 29 — 1947 Aug. 9
rms [arcsec] 2.54
orbit quality class 1a

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT) 19460410.0 = JD 2431920.5
time of perihelion passage (TT) 19460413.264312 ± 0.000368
perihelion distance 1.72412209 ± 0.00000318
eccentricity 1.00114441 ± 0.00000801
argument of perihelion [deg] 54.328447 ± 0.000213
longitude of the ascending node [deg] 129.664999 ± 0.000056
inclination [deg] 72.842650 ± 0.000056
inverse semimajor axis [10-6 au-1] -663.76 ± 4.64

Note: Epoch is given in a format: yyyymmdd.d, time of perihelion passage in a format of yyyymmdd.dddddd.



data set of C/1946 C1

Figure caption: Six 2D-projections of the 6D space of original swarm (5001 VCs) of C/1946 C1. Each density map is given in logarithmic scale presented on the right in the individual panel.
The same figure in the new window

Original orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT) 16461108
time of perihelion passage (TT) 19460412.084826 ± 0.000713
perihelion distance 1.71681103 ± 0.00000306
eccentricity 0.99999862 ± 0.00000789
argument of perihelion [deg] 54.466561 ± 0.000212
longitude of the ascending node [deg] 129.577886 ± 0.000055
inclination [deg] 72.875740 ± 0.000056
inverse semimajor axis [10-6 au-1] 0.80 ± 4.60

Note: Values of uncertainties of original/future orbital elements were derived using a swarm of 5001 osculating orbits of VCs (including the nominal osculating orbit given above) for original/future orbital evolution calclulations and then by fitting the distribution of a given orbital element of original/future swarm of VCs to Gaussian distribution.

Original barycentric positions and velocities of 5001 VCs at 250 au from the Sun are given here   (data format), i.e. before entering the planetary zone.



data set of C/1946 C1

Figure caption: Six 2D-projections of the 6D space of future swarm (5001 VCs) of C/1946 C1. Each density map is given in logarithmic scale presented on the right in the individual panel.
The same figure in the new window

Future orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT) 22500307
time of perihelion passage (TT) 19460412.859596 ± 0.000352
perihelion distance 1.72038322 ± 0.00000321
eccentricity 0.99933427 ± 0.00000791
argument of perihelion [deg] 54.182409 ± 0.000211
longitude of the ascending node [deg] 129.696232 ± 0.000055
inclination [deg] 72.941443 ± 0.000056
inverse semimajor axis [10-6 au-1] 386.97 ± 4.60


Future barycentric positions and velocities of 5001 VCs at 250 au from the Sun are given here   (data format), i.e. after leaving the planetary zone.



Non–gravitational orbit


SSDP Cometary Note C1946C1N5-001

number of observations 485
number of residuals 848
data interval 1946 Jan. 29 — 1947 Aug. 9
rms [arcsec] 2.17
orbit quality class 1b

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT) 19460410.0 = JD 2431920.5
time of perihelion passage (TT) 19460413.262573 ± 0.000674
perihelion distance 1.72409711 ± 0.00000356
eccentricity 1.00106980 ± 0.00000939
argument of perihelion [deg] 54.327041 ± 0.000428
longitude of the ascending node [deg] 129.665283 ± 0.000052
inclination [deg] 72.842371 ± 0.000054
inverse semimajor axis [10-6 au-1] -620.50 ± 5.44

Nongravitational parameters [10-8 au/day2] A1 = 1.857 ± 0.540 A2 = 3.434 ± 0.409 A3 = 0.0 (assumed)

Note: Epoch is given in a format: yyyymmdd.d, time of perihelion passage in a format of yyyymmdd.dddddd.



data set of C/1946 C1

Figure caption: Six 2D-projections of the 6D space of original swarm (5001 VCs) of C/1946 C1. Each density map is given in logarithmic scale presented on the right in the individual panel.
The same figure in the new window

Original orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT) 16450825
time of perihelion passage (TT) 19460412.089411 ± 0.000901
perihelion distance 1.71675231 ± 0.00000645
eccentricity 0.99982419 ± 0.00002185
argument of perihelion [deg] 54.469479 ± 0.000665
longitude of the ascending node [deg] 129.578179 ± 0.000053
inclination [deg] 72.875457 ± 0.000055
inverse semimajor axis [10-6 au-1] 102.41 ± 12.73

Note: Values of uncertainties of original/future orbital elements were derived using a swarm of 5001 osculating orbits of VCs (including the nominal osculating orbit given above) for original/future orbital evolution calclulations and then by fitting the distribution of a given orbital element of original/future swarm of VCs to Gaussian distribution.

Original barycentric positions and velocities of 5001 VCs at 250 au from the Sun are given here   (data format), i.e. before entering the planetary zone.



data set of C/1946 C1

Figure caption: Six 2D-projections of the 6D space of future swarm (5001 VCs) of C/1946 C1. Each density map is given in logarithmic scale presented on the right in the individual panel.
The same figure in the new window

Future orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT) 22490928
time of perihelion passage (TT) 19460412.860782 ± 0.000603
perihelion distance 1.72036623 ± 0.00000764
eccentricity 0.99940339 ± 0.00000964
argument of perihelion [deg] 54.181924 ± 0.000402
longitude of the ascending node [deg] 129.696514 ± 0.000053
inclination [deg] 72.941172 ± 0.000055
inverse semimajor axis [10-6 au-1] 346.80 ± 5.61


Future barycentric positions and velocities of 5001 VCs at 250 au from the Sun are given here   (data format), i.e. after leaving the planetary zone.





Solar System Dynamics & Planetology Group, 2014. All rights reserved

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