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 2a
orbital elements (barycentric ecliptic J2000)
Epoch 1668 06 05
perihelion date 1971 04 17.55272094 ± 0.00171974
perihelion distance [au] 1.23196157 ± 0.00003558
eccentricity 0.99954616 ± 0.00013666
argument of perihelion [°] 152.440696 ± 0.002104
ascending node [°] 104.053419 ± 0.000659
inclination [°] 109.749776 ± 0.0008
reciprocal semi-major axis [10-6 au-1] 368.38 ± 110.94
file containing 5001 VCs swarm
1971e1n1.bmi
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.
Six 2D-projections of the 6D space of original swarm including 5001 VCs. Each density map is given in logarithmic scale presented on the right in the individual panel.