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.
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 |
orbital elements (heliocentric ecliptic J2000) | ||
---|---|---|
Epoch | 2015 05 18 | |
perihelion date | 2015 05 01.76328526 | ± 0.00118776 |
perihelion distance [au] | 2.00765844 | ± 0.00004673 |
eccentricity | 1.00015874 | ± 0.00022905 |
argument of perihelion [°] | 357.537262 | ± 0.000630 |
ascending node [°] | 250.771342 | ± 0.000630 |
inclination [°] | 80.255257 | ± 0.002815 |
reciprocal semi-major axis [10-6 au-1] | -79.07 | ± 114.09 |

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).
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).