C/1995 Y1 Hyakutake
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Comet C/1995 Y1 was discovered on 25 December 1995 by Yuji Hyakutake (Japan), that is 2 months before its perihelion passage. This comet was last observed in the second half of September 1996.
Comet had its closest approach to the Earth on 15 February 1996 (1.237 au), 9 days before its perihelion passage.
Solutions given here are based on data spanning over 0.736 yr in a range of heliocentric distances: 1.43 au – 1.057 au (perihelion) – 3.16 au.It is difficult to indicate the preferred orbit and here the non-gravitational orbit giving the smallest RMS is taken as preferred.
This Oort spike comet suffers rather large planetary perturbations during its passage through the planetary system; these perturbations lead to a more tight future orbit with semimajor axis of about 1,700 au.See also Królikowska 2020.

solution description
number of observations 268
data interval 1995 12 26 – 1996 09 21
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 1.43 au – 1.36 au (perihelion) – 3.16 au
detectability of NG effects in the comet's motion comet with determinable NG~orbit
type of model of motion GR - gravitational orbit
data weighting YES
number of residuals 529
RMS [arcseconds] 0.85
orbit quality class 1b
orbital elements (heliocentric ecliptic J2000)
Epoch 1996 02 07
perihelion date 1996 02 24.28727560 ± 0.00007444
perihelion distance [au] 1.05461684 ± 0.00000055
eccentricity 1.00025534 ± 0.00000622
argument of perihelion [°] 46.348495 ± 0.000080
ascending node [°] 195.761416 ± 0.000072
inclination [°] 54.466191 ± 0.000046
recip semi-major axis [10-6 au-1] -242.12 ± 5.90
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.