C/1999 Y1 LINEAR
more info
Comet C/1999 Y1 was discovered on 20 December 1999 with Lincoln Laboratory Near-Earth Asteroid Research project, that is 3 months before its perihelion passage. Next, it was found on earlier images taken on 29 and 30 October 1999 with the same project. It was observed until 19 July 2003.
This is a comet with nongravitational effects strongly manifested in positional data fitting.
Comet had its closest approach to the Earth on 3 November 2000 (2.497 au), more than 4.5 months before its perihelion passage.
Solutions given here are based on data spanning over 3.720 yr in a range of heliocentric distances: 5.60 au – 3.091 au (perihelion) – 7.91 au.
This Oort spike comet suffers moderate planetary perturbations during its passage through the planetary system; these perturbations lead to a more tight future orbit with semimajor axis of about 3,000 au. See also Królikowska 2020.

solution description
number of observations 884
data interval 1999 10 29 – 2003 07 19
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 5.6 au – 3.09 au (perihelion) – 7.91 au
type of model of motion NC - non-gravitational orbits for symmetric CO-g(r)-like function
data weighting YES
number of residuals 1749
RMS [arcseconds] 0.48
orbit quality class 1a+
orbital elements (heliocentric ecliptic J2000)
Epoch 2001 04 01
perihelion date 2001 03 24.10336759 ± 0.00020494
perihelion distance [au] 3.09120469 ± 0.00000157
eccentricity 1.00060214 ± 0.00000346
argument of perihelion [°] 184.283096 ± 0.000053
ascending node [°] 188.883995 ± 0.000011
inclination [°] 134.786947 ± 0.000012
recip semi-major axis [10-6 au-1] -194.79 ± 1.12
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] 1.5107 ± 0.0576
A2 [10-8au/day2] 3.4846 ± 0.0813
A3 [10-8au/day2] 0.000244 ± 0.019554
m -2.00
n 3.000
k -2.6000
r0 [au] 10.000
α 0.0100