C/2008 Q3 (Garradd)

For other comets of the same name, see Comet Garradd.

Comet Garradd, formally designated as C/2008 Q3, is a non-periodic comet that was observed from August 2008 to June 2010. It is the 11th out of 17 comets discovered by Australian astronomer, Gordon J. Garradd.

C/2008 Q3 (Garradd)

Photograph of Messier 3 (left) and C/2008 Q3 (Garradd) taken by WISE on 2 January 2010.[1]
Discovery[2]
Discovered by	Gordon J. Garradd
Discovery site	Siding Spring Observatory
Discovery date	27 August 2008
Orbital characteristics[3]
Epoch	27 August 2009 (JD 2455070.5)
Observation arc	431 days (1.18 years)
Number of observations	701
Aphelion	~17,780 AU
Perihelion	1.798 AU
Semi-major axis	~8,900 AU
Eccentricity	0.99979
Orbital period	~840,000 years
Inclination	140.71°
Longitude of ascending node	219.73°
Argument of periapsis	340.86°
Mean anomaly	0.0001°
Last perihelion	23 June 2009
TJupiter	–1.286
Earth MOID	0.814 AU
Jupiter MOID	2.561 AU
Physical characteristics[4]
Mean diameter	6.7 km (4.2 mi)
Comet total magnitude (M1)	6.3
Comet nuclear magnitude (M2)	12.8

Physical characteristics

Infrared and spectroscopic observations by the Herschel Space Telescope determined that while the comet was around 1.83–1.85 AU (274–277 million km) from the Sun, its water production rate was measured at 1.7–2.8×10²⁸/s^-1.^[5] Data obtained by Akari detected a relatively high CO/CO
₂ ratio for such a dynamically new comet, which may be caused by an outburst event prior to being observed by the satellite itself.^[6]

Its nucleus is estimated to have an effective diameter of 6.7 km (4.2 mi),^[4] with a mass roughly about 1×10¹² kg (2.2×10¹² lb).^[7]