C/1993 A1 Mueller
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Comet C/1993 A1 was discovered on 2 January 1993 by Jean Mueller (Palomar Sky Survey II). Later, a prediscovery image of this comet taken on 26 November 1992 (Catalina Station, Tucson) was found.At the moment of discovery, this comet was a year before its perihelion passage and it was last observed in the mid-August 1994.
Comet had its closest approach to the Earth on 13 November 1993 (1.713 au), 2 months before its perihelion passage.
This is a comet with nongravitational effects strongly manifested in positional data fitting.
Preferred solution given here is based on data spanning over 1.72 yr in a range of heliocentric distances: 4.89 au – 1.94 au (perihelion) – 3.19 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 2020.

solution description
number of observations 739
data interval 1992 11 26 – 1994 08 17
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 4.89 au – 1.94 au (perihelion) – 3.19 au
type of model of motion NC - non-gravitational orbits for symmetric CO-g(r)-like function
data weighting YES
number of residuals 1467
RMS [arcseconds] 0.87
orbit quality class 1a
orbital elements (barycentric ecliptic J2000)
Epoch 1694 03 01
perihelion date 1994 01 13.84050835 ± 0.00071213
perihelion distance [au] 1.94243499 ± 0.00000734
eccentricity 0.99999369 ± 0.00000592
argument of perihelion [°] 130.672581 ± 0.000259
ascending node [°] 144.723896 ± 0.000042
inclination [°] 124.970624 ± 0.000048
reciprocal semi-major axis [10-6 au-1] 3.25 ± 3.05
file containing 5001 VCs swarm
1993a1c5.bmi
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.
Six 2D-projections of the 6D space of original swarm including 5001 VCs. Each density map is given in logarithmic scale presented on the right in the individual panel.