P/2011 S1 (Gibbs)

For other comets discovered by Alex R. Gibbs, see Comet Gibbs.

P/2011 S1 (Gibbs) is a periodic comet or an active centaur with a 25-year orbit around the Sun.

P/2011 S1 (Gibbs)

Discovery[1]
Discovered by	Alex R. Gibbs
Discovery site	Mount Lemmon Survey
Discovery date	19 September 2011
Orbital characteristics[2]
Epoch	5 June 2013 (JD 2456448.5)
Observation arc	8.26 years
Earliest precovery date	29 September 2010
Number of observations	148
Aphelion	10.409 AU
Perihelion	6.894 AU
Semi-major axis	8.652 AU
Eccentricity	0.20315
Orbital period	25.448 years
Inclination	2.679°
Longitude of ascending node	218.89°
Argument of periapsis	193.37°
Mean anomaly	342.76°
Last perihelion	24 August 2014
Next perihelion	2 November 2039[3]
TJupiter	3.124
Earth MOID	5.903 AU
Jupiter MOID	1.885 AU
Physical characteristics[2]
Mean radius	4.0 km (2.5 mi)[4]
Spectral type	(B–V) = 0.96±0.11[5] (V–R) = 0.11±0.09[6] (R–I) = 0.26±0.06[6] (B–R) = 1.55±0.11[5]
Comet total magnitude (M1)	7.1
Comet nuclear magnitude (M2)	11.5

Discovery

American astronomer, Alex R. Gibbs, reported the discovery of a new object from CCD images obtained from the 1.5 m (4.9 ft) reflector telescope from the Mount Lemmon Survey on 19 September 2011.^[1] Precovery images show that the object produced comet-like activity as early as September 2010, a year before its discovery.^[6]