C/2015 V2 Johnson
more info
Comet C/2015 V2 was discovered on 3 November 2015 by Jess A. Johnson (Catalina Sky Survey), that is about a year and seven months before its perihelion passage. Next, 14 pre-discovery data were found going back to beginning of 2015 (January 11). Comet was observed extensively until 27 October 2019. C/2015 V2 had closest approach to the Earth on 4 June 2017 (0.811 au, about a week before the perihelion passage).

This is a comet with NG effects strongly manifested in positional data fitting. Solutions 'a7' and 'n5' (preferred) are based on data spanning over 4.79 yr in a wide range of heliocentric distances: 8.79 au – 1.637 au (perihelion) – 8.04 au. GR solution 'ba' differ from 'a7' in the method of data weighting, silimarly the pair of NG solutions 'bn' and 'n5'. NG parameters are well determined for solutions 'n5' and 'bn' and are similar. Though many large trends in [O-C] that exist for the GR solution were eliminated thanks to incorporating the NG forces with constant NG parameters, both NG solutions displayed some tiny trends in [O-C]. In our opinion, the better is [O-C] for solution 'n5'. Thus, we suggest this solution be treated as preferred. Alternatively, the solution 'pn' (based on the pre-perihelion orbital leg) can also be taken for the study of the origin of this comet.

This Oort Cloud comet suffers moderate planetary perturbations while passing through the planetary system; these perturbations lead to escape the comet from the planetary zone on a hyperbolic orbit (see future barycentric orbits for all orbits given here).
solution description
number of observations 5950
data interval 2015 01 11 – 2019 10 27
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 8.79 au – 1.64 au (perihelion) – 8.04 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 11668
RMS [arcseconds] 0.33
orbit quality class 1a+
orbital elements (heliocentric ecliptic J2000)
Epoch 2017 06 16
perihelion date 2017 06 12.33936989 ± 0.00001267
perihelion distance [au] 1.63698830 ± 0.00000013
eccentricity 1.00172721 ± 0.00000053
argument of perihelion [°] 164.895458 ± 0.000008
ascending node [°] 69.848855 ± 0.000003
inclination [°] 49.87667 ± 0.000005
reciprocal semi-major axis [10-6 au-1] -1,055.12 ± 0.32
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] 2.3114 ± 0.014
A2 [10-8au/day2] -0.40398 ± 0.01209
A3 [10-8au/day2] -0.49255 ± 0.00833
m -2.15
n 5.093
k -4.6142
r0 [au] 2.808
α 0.1113