C/2016 U1 NEOWISE
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Comet C/2016 U1 was discovered on 21 October 2016 by Near-Earth Object Wide-field Infrared Survey Explorer, that is less than 3 months before its perihelion passage, and was astrometrically observed until 12 January 2017. Comet had closest approach to the Earth on 13 December 2016 (0.709 au, about a month before the perihelion passage).
Sekanina (2019) concluded that this comet was a rare example of a comet that survived its perihelion passage despite a small distance from the Sun at that moment (see his Tables 2 and 6).
Despite short data arc this is a comet with NG effects determinable using positional data fitting. Both solutions (GR and NG) are based on data spanning over 0.227 yr in the pre-perihelion orbital leg, in a range of heliocentric distances from 1.86 au to 0.321 au.
GR assumption gives original hyperbolic orbit; however, NG orbit results in original semimajor axis of about 1900–3300 au (uncertainty of one sigma is used). C/2016 K1 suffers moderate/large planetary perturbations while passing through the planetary system; these perturbations probably lead to escape the comet from the planetary zone on a hyperbolic orbit (see future barycentric orbits).
Sekanina (2019) concluded that this comet was a rare example of a comet that survived its perihelion passage despite a small distance from the Sun at that moment (see his Tables 2 and 6).
Despite short data arc this is a comet with NG effects determinable using positional data fitting. Both solutions (GR and NG) are based on data spanning over 0.227 yr in the pre-perihelion orbital leg, in a range of heliocentric distances from 1.86 au to 0.321 au.
GR assumption gives original hyperbolic orbit; however, NG orbit results in original semimajor axis of about 1900–3300 au (uncertainty of one sigma is used). C/2016 K1 suffers moderate/large planetary perturbations while passing through the planetary system; these perturbations probably lead to escape the comet from the planetary zone on a hyperbolic orbit (see future barycentric orbits).
| solution description | ||
|---|---|---|
| number of observations | 382 | |
| data interval | 2016 10 21 – 2017 01 12 | |
| data type | observed only before perihelion (PRE) | |
| data arc selection | entire data set (STD) | |
| range of heliocentric distances | 1.86 au – 0.321au | |
| type of model of motion | NS - non-gravitational orbits for standard g(r) | |
| data weighting | YES | |
| number of residuals | 757 | |
| RMS [arcseconds] | 0.80 | |
| orbit quality class | 2b | |
| orbital elements (barycentric ecliptic J2000) | ||
|---|---|---|
| Epoch | 2304 12 09 | |
| perihelion date | 2017 01 13.79678294 | ± 0.00081097 |
| perihelion distance [au] | 0.31931724 | ± 0.00001825 |
| eccentricity | 1.00027455 | ± 0.00003069 |
| argument of perihelion [°] | 162.739986 | ± 0.001922 |
| ascending node [°] | 61.495130 | ± 0.001843 |
| inclination [°] | 46.403746 | ± 0.001423 |
| reciprocal semi-major axis [10-6 au-1] | -859.80 | ± 96.09 |
| file containing 5001 VCs swarm |
|---|
| 2016u1n4.bpl |
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).
Six 2D-projections of the 6D space of future swarm including 5001 VCs. Each density map is given in logarithmic scale presented on the right in the individual panel.