C/2015 X7 ATLAS
more info
Comet C/2015 X7 was discovered on 12 December 2015 by Asteroid Terrestrial-impact Last Alert System (ATLAS) Team, that is about 7.5 months before its perihelion passage. Some prediscovery images of this comet were found: taken on 28 January 2015 by Pan-STARRS 1, Haleakala. This comet was observed until 16 June 2017.
Comet had its closest approach to the Earth on 8 February 2017 (5.909 au); about 6 months after its perihelion passage.
Solutions given here are based on data spanning over 2.38 yr in a range of heliocentric distances: 5.95 au – 3.685 au (perihelion) – 4.64 au.
This Oort spike comet suffers small planetary perturbations during its passage through the planetary system that lead to a more tight future orbit with a semimajor axis of about 5,000 au (see future barycentric orbits).

solution description
number of observations 628
data interval 2015 01 28 – 2017 06 16
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 5.95 au – 3.69 au (perihelion) – 4.64 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 1239
RMS [arcseconds] 0.44
orbit quality class 1a+
orbital elements (heliocentric ecliptic J2000)
Epoch 2016 07 31
perihelion date 2016 07 30.23332213 ± 0.00033015
perihelion distance [au] 3.68453191 ± 0.00000120
eccentricity 1.00175589 ± 0.00000278
argument of perihelion [°] 348.485633 ± 0.000051
ascending node [°] 139.883839 ± 0.000006
inclination [°] 57.580939 ± 0.000007
reciprocal semi-major axis [10-6 au-1] -476.56 ± 0.75
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.