C/1989 X1 Austin
more info
Comet C/1989 X1 was discovered on 6 December 1989 by Rodney R.D. Austin (New Plymouth, New Zealand), that is about 4 months before its perihelion passage. This comet was last observed in late June 1990.
Comet had its closest approach to the Earth on 25 May 1990 (0.237 au), about 1.5 month after perihelion passage.
Solutions given here are based on data spanning over 0.556 yr in a range of heliocentric distances: 2.44 au – 0.350 au (perihelion) – 1.74 au.
This Oort spike comet suffers moderate planetary perturbations during its passage through the planetary system; these perturbations lead to escape the comet on hyperbolic orbit from the planetary zone.
See also Królikowska 2014 and Królikowska 2020.

solution description
number of observations 275
data interval 1989 12 06 – 1990 06 27
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 2.44 au – 0.35 au (perihelion) – 1.74 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 537
RMS [arcseconds] 1.28
orbit quality class 1b
orbital elements (heliocentric ecliptic J2000)
Epoch 1990 04 19
perihelion date 1990 04 09.96750355 ± 0.00003320
perihelion distance [au] 0.34977206 ± 0.00000053
eccentricity 1.00021594 ± 0.00000309
argument of perihelion [°] 61.575932 ± 0.000097
ascending node [°] 75.925341 ± 0.000017
inclination [°] 58.95643 ± 0.000065
recip semi-major axis [10-6 au-1] -617.36 ± 8.83
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 parameters
A1 [10-8au\day-2] 0.26679 ± 0.0729
A2 [10-8au\day-2] 0.032565 ± 0.022103
A3 [10-8au\day-2] 0 (assumed)
m -2.15
n 5.093
k -4.6142
r0 [au] 2.808
α 0.1113