C/2015 K4 PanSTARRS
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Comet C/2015 K4 was discovered on 24 May 2015 by Pan-STARRS 1, Haleakala, that is about three weeks after its perihelion passage. Comet was observed for less than two months until 14 July 2015. C/2015 K4 had closest approach to the Earth on 25 May 2015 (1.061 au, 3.5 weeks after the perihelion passage).

This is a comet with a short data arc and we show here two GR solutions differing in data treatment: 'a5' (data were weighting) and 'a1' (weighting procedure was omitted); bothare based on data spanning over 0.14 yr in a narrow range of heliocentric distances from 2.03 au to 2.20 au.

According to both GR solutions, original semimajor axis of C/2015 K4 is about 1100–1800 au (uncertainty of one sigma was included). Due to moderate planetary perturbations, its future orbit will be much looser; it is uncertain whether this comet will leave the solar system in a hyperbolic orbit.
solution description
number of observations 134
data interval 2015 05 24 – 2015 07 14
data type observed only after perihelion (POST)
data arc selection entire data set (STD)
range of heliocentric distances 2.03 au – 2.2au
detectability of NG effects in the comet's motion NG effects not determinable
type of model of motion GR - gravitational orbit
data weighting YES
number of residuals 259
RMS [arcseconds] 0.35
orbit quality class 2b
previous orbit statistics, both Galactic and stellar perturbations were taken into account
no. of returning VCs in the swarm 5001 *
no. of escaping VCs in the swarm 0
no. of hyperbolas among escaping VCs in the swarm 0
previous reciprocal semi-major axis [10-6 au-1] 533.79 – 678.37 – 826.69
previous perihelion distance [au] 2.00646 – 2.0066 – 2.0068
previous aphelion distance [103 au] 2.4 – 2.9 – 3.7
time interval to previous perihelion [Myr] 0.042 – 0.056 – 0.081
percentage of VCs with qprev < 10100
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).
previous_g orbit statistics, here only the Galactic tide has been included
no. of returning VCs in the swarm 5001 *
no. of escaping VCs in the swarm 0
no. of hyperbolas among escaping VCs in the swarm 0
previous reciprocal semi-major axis [10-6 au-1] 533.79 – 678.37 – 826.69
previous perihelion distance [au] 2.00636 – 2.00644 – 2.00657
previous aphelion distance [103 au] 2.4 – 2.9 – 3.7
time interval to previous perihelion [Myr] 0.042 – 0.056 – 0.081
percentage of VCs with qprev < 10100