C/2005 EL173 LONEOS
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C/2005 EL173 was discovered on 8 March 2005 by the LONEOS as an apparently asteroidal object in a retrograde orbit and semimajor axis of 36 au [MPEC 2005-F48, 2005 March 29]. Therefore it was initially classified as cubewano or scattered disc object in MPC. Its cometary apperance was reported by A. Fitzsimmons on 10 May 2005. C/2005 EL173 was observed until mid-November 2008.

This comet made its closest approach to the Earth on 4 January 2007 (3.310 au), two months before perihelion passage.

Solutions given here are based on data spanning over 3.7 yr in a range of heliocentric distances: 7.12 au – 3.886 au (perihelion) – 6.45 au.

NG orbit using full data-arc is determinable.

This Oort spike comet suffers rather slight planetary perturbations during its passage through the planetary system; however, these perturbations leas to escape this comet from the planetary zone on a hyperbolic orbit.

See also Królikowska and Dones 2023, Królikowska and Dybczyński 2017,and Królikowska 2014.
solution description
number of observations 231
data interval 2005 03 03 – 2007 03 01
data arc selection data generally limited to pre-perihelion (PRE)
range of heliocentric distances 7.12 au – 3.89au
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 457
RMS [arcseconds] 0.43
orbit quality class 1a
orbital elements (heliocentric ecliptic J2000)
Epoch 2007 03 01
perihelion date 2007 03 05.87341017 ± 0.00078594
perihelion distance [au] 3.88631576 ± 0.00000543
eccentricity 1.00335276 ± 0.00000499
argument of perihelion [°] 261.493946 ± 0.000142
ascending node [°] 344.796418 ± 0.000013
inclination [°] 130.679662 ± 0.000019
reciprocal semi-major axis [10-6 au-1] -862.71 ± 1.28
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).