C/1971 E1 Toba
more info
Comet C/1971 E1 was discovered on 7 March 1971 by Kenji Toba (Tsuchiura, Ibaraki, Japan), that is more than a month before its perihelion passage. It was observed until 9 September 1971 [Kronk, Cometography: Volume 5].
Comet had its closest approach to the Earth on 9 June 1971 (0.724 au), about a month and 3 weeks after its perihelion passage.
Solutions given here are based on data spanning over 0.504 yr in a range of heliocentric distances: 1.37 au – 1.233 au (perihelion) – 2.41 au.
This comet suffers moderate planetary perturbations during its passage through the planetary system; according to preferred solution these perturbations lead to escape the comet from the planetary zone on a hyperbolic orbit (see future barycentric orbits).
See also Królikowska 2020.

solution description
number of observations 137
data interval 1971 03 09 – 1971 09 09
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 1.37 au – 1.23 au (perihelion) – 2.41 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 275
RMS [arcseconds] 1.22
orbit quality class 2b
orbital elements (heliocentric ecliptic J2000)
Epoch 1971 03 30
perihelion date 1971 04 17.23119995 ± 0.02415217
perihelion distance [au] 1.23314752 ± 0.00016341
eccentricity 1.00005767 ± 0.00089959
argument of perihelion [°] 152.344821 ± 0.023268
ascending node [°] 104.072813 ± 0.002631
inclination [°] 109.677463 ± 0.007621
reciprocal semi-major axis [10-6 au-1] -46.76 ± 729.50
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] 6.1493 ± 1.2619
A2 [10-8au/day2] 2.6915 ± 7.6946
A3 [10-8au/day2] -0.83932 ± 0.32962
m -2.15
n 5.093
k -4.6142
r0 [au] 2.808
α 0.1113