C/2009 P2

Solar System
Dynamics &
Planetology
Group

C/2009 P2 Boattini

General description

C/2009 P2 was discovered by A. Boattini on 15 August 2009 during the Catalina Sky Survey with the 0.68 m Schmidt; its cometary apperance was next confirmed by several amateur observers. Later, positional observations of C/2009 P2 were linked with data of two asteroidal objects: 2008 TQ₁₃₇ and 2008 VP₂₈ taken between 1–9 October 2008 [MPEC 2009-R29, 2009 Sept. 9].

This comet made its closest approaches to Earth on 21 September 2009 (5.649 au, 4.7 months before perihelion) and 17 August 2010 (5.704 au, 6.2 months after perihelion).

Solution given below is based on data span over 2.8 yr in a range of heliocentric distances: 7.33 au – 6.544 au (perihelion) – 7.53 au.

Comet suffered a a very slight planetary perturbations during its passage through the planetary system.

Figure caption: 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.

SSDP Cometary Note C2009P2A5-001

Comet C/2009 P2 Boattini

number of observations	503
number of residuals	982
data interval	2008 Oct. 1 — 2011 Aug. 27
rms [arcsec]	0.51
orbit quality class	1a

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	20100213.0	= JD 2455240.5
time of perihelion passage (TT)	20100210.863085	± 0.001278
perihelion distance	6.54387710	± 0.00000891
eccentricity	1.00183747	± 0.00000903
argument of perihelion [deg]	76.088005	± 0.000124
longitude of the ascending node [deg]	60.392108	± 0.000066
inclination [deg]	163.455157	± 0.000011
inverse semimajor axis [10^-6 au^-1]	-280.79	± 1.38

Note: Epoch is given in a format: yyyymmdd.d, time of perihelion passage in a format of yyyymmdd.dddddd.

Figure caption: Six 2D-projections of the 6D space of original swarm (5001 VCs) of C/2009 P2. Each density map is given in logarithmic scale presented on the right in the individual panel.
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Original orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT)	17020119
time of perihelion passage (TT)	20100211.788872	± 0.001311
perihelion distance	6.54119059	± 0.00000894
eccentricity	0.99986297	± 0.00000906
argument of perihelion [deg]	76.054900	± 0.000126
longitude of the ascending node [deg]	60.336867	± 0.000066
inclination [deg]	163.445524	± 0.000011
inverse semimajor axis [10^-6 au^-1]	20.95	± 1.38

Note: Values of uncertainties of original/future orbital elements were derived using a swarm of 5001 osculating orbits of VCs (including the nominal osculating orbit given above) for original/future orbital evolution calclulations and then by fitting the distribution of a given orbital element of original/future swarm of VCs to Gaussian distribution.

Original barycentric positions and velocities of 5001 VCs at 250 au from the Sun are given here (data format), i.e. before entering the planetary zone.

Future orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT)	23180709
time of perihelion passage (TT)	20100210.745514	± 0.001296
perihelion distance	6.54247976	± 0.00000888
eccentricity	0.99968814	± 0.00000906
argument of perihelion [deg]	76.230546	± 0.000126
longitude of the ascending node [deg]	60.497239	± 0.000066
inclination [deg]	163.451272	± 0.000011
inverse semimajor axis [10^-6 au^-1]	47.67	± 1.39