C/1999 U4 Catalina-Skiff
more info
C/1999 U4 was discovered on 31 October 1999 by the Catalina Sky Survey, and, independently, on 1 November by B.A. Skiff under LONEOS Survey. At once, its cometary apperance was reported [IAUC 7298, 1999 November 1]. Later, pre-discovery detections from 18 September and 30 October 1999 were found.
This comet made its closest approach to the Earth on 11 January 2002 (4.415 au), 2.5 months after perihelion.
Solutions given here are based on data spanning over 4.6 yr in a range of heliocentric distances: 7.55 au – 4.915 au (perihelion) – 8.22 au.
This Oort spike comet suffers moderate planetary perturbations during its passage through the planetary system that lead to escape of the comet from the solar system on hiperbolic orbit (see future barycentric orbit).
See also Królikowska 2014 and Królikowska and Dybczyński 2017.

solution description
number of observations 911
data interval 1999 09 18 – 2004 04 11
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 7.55 au – 4.92 au (perihelion) – 8.22 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 1807
RMS [arcseconds] 0.75
orbit quality class 1a+
orbital elements (heliocentric ecliptic J2000)
Epoch 2001 10 18
perihelion date 2001 10 28.46167943 ± 0.00077141
perihelion distance [au] 4.91529774 ± 0.00000550
eccentricity 1.00763318 ± 0.00000590
argument of perihelion [°] 77.512620 ± 0.000105
ascending node [°] 32.288890 ± 0.000013
inclination [°] 51.926235 ± 0.000012
recip semi-major axis [10-6 au-1] -1,552.94 ± 1.20
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] 0.88288 ± 0.15679
A2 [10-8au/day2] -1.244 ± 0.1835
A3 [10-8au/day2] 1.7011 ± 0.025
m -2.00
n 3.000
k -2.6000
r0 [au] 10.000
α 0.0100