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 1374
data interval 2019 06 10 – 2020 09 08
data arc selection data generally limited to pre-perihelion (PRE)
range of heliocentric distances 6.05 au – 2.03au
type of model of motion NC - non-gravitational orbits for symmetric CO-g(r)-like function
data weighting YES
number of residuals 2710
RMS [arcseconds] 0.32
orbit quality class 1b
orbital elements (heliocentric ecliptic J2000)
Epoch 2020 12 17
perihelion date 2020 12 01.80754684 ± 0.00053040
perihelion distance [au] 1.70458849 ± 0.00000664
eccentricity 0.99977334 ± 0.00001560
argument of perihelion [°] 193.446367 ± 0.000446
ascending node [°] 13.573574 ± 0.000084
inclination [°] 82.427486 ± 0.000106
reciprocal semi-major axis [10-6 au-1] 132.97 ± 9.15
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] 1.7665 ± 0.1848
A2 [10-8au/day2] -0.8135 ± 0.12632
A3 [10-8au/day2] 0.02743 ± 0.06707
m -2.00
n 3.000
k -2.6000
r0 [au] 10.000
α 0.0100