Solar System
Dynamics &
Planetology
Group 		C/2017 K2 PANSTARRS older solution



General description

data set of C/2017 K2

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Comet C/2017 K2 was discovered in May 2017, when it was 16.09 au from the Sun; precovery images from 2013 and 2015 were next found. This comet will pass perihelion on 21 December 2022 at the distance of 1.81 au from the Sun.

Solution given below is based on data span over 4.70 yr in a range of heliocentric distances from 23.740 au to 14.65 au.

More details in Królikowska and Dybczyński 2018


Figure caption: Heliocentric (thin red curve) and geocentric (green curve) distance of C/2017 K2 during the time interval used for orbit determination. Time distribution of positional observations of C/2017 K2 with corresponding heliocentric distance at which they were taken is shown as red dots. The geocentric distances of measurements are given as green dots but they are almost covered by red dots due to similarly large distances from the Sun and the Earth. Figure taken from Królikowska and Dybczyński 2018


SSDP Cometary Note C2017K2A5-001

Comet C/2017 K2 — PANSTARRS

number of observations 450
number of residuals 889
data interval 2013 May 12 — 2018 Jan. 23
rms [arcsec] 0.38
orbit quality class

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT) 20170705.0 = JD 2457939.5
time of perihelion passage (TT) 20221221.412478 ± 0.030195
perihelion distance 1.81086204 ± 0.00005500
eccentricity 1.00032653 ± 0.00001443
argument of perihelion [deg] 236.021084 ± 0.001710
longitude of the ascending node [deg] 88.181668 ± 0.000236
inclination [deg] 87.553729 ± 0.000023
inverse semimajor axis [10-6 au-1] -180.32 ± 7.96

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

Epoch (TT) 17221020
time of perihelion passage (TT) 20221218.855081 ± 0.029861
perihelion distance 1.79551272 ± 0.00005475
eccentricity 0.99991296 ± 0.00001423
argument of perihelion [deg] 236.214199 ± 0.001702
longitude of the ascending node [deg] 88.086028 ± 0.000236
inclination [deg] 87.573197 ± 0.000023
inverse semimajor axis [10-6 au-1] 48.48 ± 7.93

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.

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

Epoch (TT) 23360713
time of perihelion passage (TT) 20221219.872785 ± 0.030085
perihelion distance 1.79335881 ± 0.00005584
eccentricity 0.99795491 ± 0.00001431
argument of perihelion [deg] 236.051977 ± 0.001691
longitude of the ascending node [deg] 88.254521 ± 0.000240
inclination [deg] 87.789103 ± 0.000017
inverse semimajor axis [10-6 au-1] 1140.37 ± 8.02


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, 2018. All rights reserved

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