C/2012 K1 (PanSTARRS)

Not to be confused with the comet C/2011 L4 (PanSTARRS) that became bright in March 2013.

C/2012 K1 (PanSTARRS) is a retrograde Oort cloud comet discovered at magnitude 19.7, 8.7 AU from the Sun on 17 May 2012 using the Pan-STARRS telescope located near the summit of Haleakalā, on the island of Maui in Hawaii (U.S.).^[1]

C/2012 K1 (PanSTARRS)

NEOWISE series of infrared images of C/2012 K1 on 20 May 2014
Discovery
Discovered by	Pan-STARRS 1.8-m Ritchey–Chrétien (F51)[1]
Discovery date	17 May 2012
Orbital characteristics
Epoch	11 August 2014[2]
Orbit type	Oort cloud
Aphelion	~52000 AU (inbound)[3] ~14000 AU (outbound)
Perihelion	1.0545 AU (q)[2]
Eccentricity	1.00021[2]
Orbital period	several million years inbound (Barycentric solution for epoch 1950)[3] ~600000 yr outbound (Barycentric solution for epoch 2050)[3]
Inclination	142.43°[2]
Last perihelion	27 August 2014[2]
Jupiter MOID	1.5 AU
Physical characteristics[4][5]
Dimensions	2.4–4.4 km (1.5–2.7 mi)
Mean diameter	3.4 km (2.1 mi)
Synodic rotation period	9.4±0.4 hours

The comet started 2014 as a Northern Hemisphere object. By late April 2014 it had brightened to roughly apparent magnitude ~8.8^[6] making it a small telescope/binoculars target for experienced observers. In June and July 2014 the comet was near the Sickle of Leo.^[7] As of 3 July 2014 the comet had brightened to magnitude 7.9.^[8]

From 12 July 2014 until 6 September 2014 it had an elongation less than 30 degrees from the Sun.^[6] The comet came to perihelion (closest approach to the Sun) on 27 August 2014 at a distance of 1.05 AU (157,000,000 km; 98,000,000 mi) from the Sun.^[2] It crosses the celestial equator on 15 September 2014 becoming a Southern Hemisphere object.^[6]

The comet peaked around magnitude 6.9 in mid-October 2014^[9][10] when it had an elongation of around 75 degrees from the Sun.^[6] It is visible in binoculars and small telescopes.