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 658
data interval 1992 11 26 – 1994 01 08
data arc selection data generally limited to pre-perihelion (PRE)
range of heliocentric distances 4.89 au – 1.94au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 1306
RMS [arcseconds] 1.14
orbit quality class 1a
orbital elements (heliocentric ecliptic J2000)
Epoch 1994 01 08
perihelion date 1994 01 12.88680955 ± 0.00466542
perihelion distance [au] 1.93750766 ± 0.00001825
eccentricity 1.00152238 ± 0.00007975
argument of perihelion [°] 130.658073 ± 0.002438
ascending node [°] 144.722815 ± 0.000443
inclination [°] 124.877957 ± 0.000088
reciprocal semi-major axis [10-6 au-1] -785.74 ± 41.15
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/day2] 24.029 ± 1.489
A2 [10-8au/day2] -13.462 ± 3.961
A3 [10-8au/day2] 0.5885 ± 1.0529
m -2.15
n 5.093
k -4.6142
r0 [au] 2.808
α 0.1113