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 CT - non-gravitational orbits for assymetric CO-g(r)-like function
data weighting YES
number of residuals 1467
RMS [arcseconds] 0.87
orbit quality class 1a
orbital elements (heliocentric ecliptic J2000)
Epoch 1994 01 08
perihelion date 1994 01 12.88339281 ± 0.00039745
perihelion distance [au] 1.93753403 ± 0.00000240
eccentricity 1.00174412 ± 0.00000562
argument of perihelion [°] 130.656645 ± 0.000192
ascending node [°] 144.722381 ± 0.000025
inclination [°] 124.877941 ± 0.000023
recip semi-major axis [10-6 au-1] -900.17 ± 2.90
Upper panel: 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.
Lower panel (panels): O-C diagram for this(two) solution (solutions) given in this database, where residuals in right ascension are shown using magenta dots and in declination by blue open circles.
non-gravitational parameters
A1 [10-8au\day-2] 6.1404 ± 0.1344
A2 [10-8au\day-2] -0.01563 ± 0.11066
A3 [10-8au\day-2] -0.085185 ± 0.0241
m -2.00
n 3.000
k -2.6000
r0 [au] 10.000
α 0.0100
ΔT [days] -1.2520 ± 6.13