C/2019 N1 ATLAS
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Comet C/2019 N1 was discovered on 5 Julyber 2019 by ATLAS-MLO, Mauna Loa, that is about 7 months before its perihelion passage. Next, two series of pre-discovery data were found going back to June 10. Comet was observed until 29 January 2022. C/2019 N1 had closest approach to the Earth on 8 February 2021 (1.913 au, morew than two months after the perihelion passage).

This is a comet with NG effects strongly manifested in positional data fitting. During GR orbit determination the series of measurements since 30 January 2022 wereejected due to large rersiduals and extremely low weights for all remaining post-perihelion observations were obtained (see [O-C] picture for 'a5' solution). Therefore, this GR orbit ('a5') is based on data spanning over 2.64 yr in a range of heliocentric distances: 6.05 au – 1.705 au (perihelion) – 5.05 au. During NG orbit determination weights in post-perihelion leg are also systematically small but notable larger than in the GR case and the full post-perihelion data arc were included. So, NG orbit ('n5') is based on data spanning over 3.23 yr in a range of heliocentric distances: 6.05 au – 1.705 au (perihelion) – 5.05 au. We suggest, this 'n5' orbit to be treated as 'preferred' for the dynamical study. Solution 'pa' represents GR orbit resulting from the entire pre-periheliuon data arc, and solutions 'pd' (GR) and'dd' (NG solution based on g(r)-formula for more volatile ices than water ice) are orbits obtained using the distant pre-perihelion data arc (heliocentric distance larger than 2.03 au).

This Oort spike comet suffers large planetary perturbations while passing through the planetary system; these perturbations lead to a definitely more tight future orbit with semimajor axis of about 1000 au (see future barycentric orbits).
solution description
number of observations 1551
data interval 2019 06 10 – 2022 09 01
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 6.05 au – 1.71 au (perihelion) – 6.86 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 3004
RMS [arcseconds] 0.35
orbit quality class 1a
orbital elements (barycentric ecliptic J2000)
Epoch 2331 10 09
perihelion date 2020 12 01.96549372 ± 0.00016111
perihelion distance [au] 1.70798881 ± 0.00000100
eccentricity 0.99837923 ± 0.00000323
argument of perihelion [°] 193.404405 ± 0.000086
ascending node [°] 13.481031 ± 0.000012
inclination [°] 82.545307 ± 0.000016
reciprocal semi-major axis [10-6 au-1] 948.94 ± 1.89
file containing 5001 VCs swarm
2019n1n5.bpl
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).
Six 2D-projections of the 6D space of future swarm including 5001 VCs. Each density map is given in logarithmic scale presented on the right in the individual panel.