C/2015 O1 PANSTARRS
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Comet C/2015 O1 was discovered on 19 July 2015 with Pan-STARRS 1 telescope (Haleakala), that is about  months after its perihelion passage.

Some prediscovery images of this comet were found: taken on 15 and 17 of June 2015 by Space Surveillance Telescope (Atom Site).

Solutions given here are based on data spanning over 4.76 yr in a range of heliocentric distances: 8.65 au – 3.730 au (perihelion) – 7.28 au.

NG orbits using full data-arc as well as independently using pre-perihelion and post-perihelion data are determinable.

See also Królikowska and Dones 2023.
solution description
number of observations 4142
data interval 2015 06 15 – 2020 03 20
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 8.65 au – 3.73 au (perihelion) – 7.28 au
type of model of motion NH - non-gravitational orbits for water sublimation from subsolar point
data weighting YES
number of residuals 8242
RMS [arcseconds] 0.48
orbit quality class 1a+
orbital elements (heliocentric ecliptic J2000)
Epoch 2018 03 23
perihelion date 2018 02 19.03697613 ± 0.00007401
perihelion distance [au] 3.72964394 ± 0.00000079
eccentricity 0.99995442 ± 0.00000117
argument of perihelion [°] 89.596320 ± 0.000016
ascending node [°] 299.857480 ± 0.000004
inclination [°] 127.211014 ± 0.000003
reciprocal semi-major axis [10-6 au-1] 12.22 ± 0.31
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.
Middle panel(s): O-C diagram for a given solution (sometimes in comparison to another solution available in CODE), where residuals in right ascension are shown using magenta dots and in declination by blue open circles.
Lowest panel: Relative weights for a given data set(s).
non-gravitational parameters
A1 [10-8au/day2] 9.2752 ± 0.0694
A2 [10-8au/day2] -3.5323 ± 0.0728
A3 [10-8au/day2] 0.71618 ± 0.02079
m -2.00
n 3.000
k -2,752.4000
r0 [au] 50.000
α 0.0003