C/2008 P1

Solar System
Dynamics &
Planetology
Group

C/2008 P1 Garradd

General description

C/2008 P1 was discovered by G. J. Garradd on 13 August 2008 on images taken with the 0.5-m Uppsala Schmidt telescope at Siding Spring; its cometary apperance was next confirmed by C. Jacques and E. Pimentel (Belo Horizonte, Minas Gerais, Brazil, 0.30-m reflector) [IAUC 8965, 2008 August 15].

This comet made its closest approach to Earth on 22 September 2009 (3.028 au), two months after perihelion.

Solution given below is based on data span over 2.5 yr in a range of heliocentric distances: 4.88 au – 3.896 au (perihelion) – 6.08 au.

Comet suffered a small 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 C2008P1A5-001

Comet C/2008 P1 Garradd

number of observations	1373
number of residuals	2691
data interval	2008 Aug. 13 — 2011 Feb. 4
rms [arcsec]	0.46
orbit quality class	1a+

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	20090728.0	= JD 2455040.5
time of perihelion passage (TT)	20090722.935905	± 0.000243
perihelion distance	3.89610720	± 0.00000108
eccentricity	1.00176244	± 0.00000214
argument of perihelion [deg]	11.862585	± 0.000040
longitude of the ascending node [deg]	357.676590	± 0.000005
inclination [deg]	64.308943	± 0.000009
inverse semimajor axis [10^-6 au^-1]	-452.36	± 0.55

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/2008 P1. Each density map is given in logarithmic scale presented on the right in the individual panel.
The same figure in the new window

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

Epoch (TT)	17040727
time of perihelion passage (TT)	20090722.891761	± 0.000239
perihelion distance	3.89043249	± 0.00000111
eccentricity	0.99941649	± 0.00000214
argument of perihelion [deg]	11.963829	± 0.000039
longitude of the ascending node [deg]	357.736840	± 0.000005
inclination [deg]	64.317061	± 0.000009
inverse semimajor axis [10^-6 au^-1]	149.98	± 0.55

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)	23150725
time of perihelion passage (TT)	20090722.386462	± 0.000239
perihelion distance	3.89265287	± 0.00000102
eccentricity	0.99906391	± 0.00000214
argument of perihelion [deg]	11.780623	± 0.000039
longitude of the ascending node [deg]	357.715831	± 0.000005
inclination [deg]	64.320996	± 0.000009
inverse semimajor axis [10^-6 au^-1]	240.48	± 0.55