C/2016 U1 (NEOWISE)

For other comets discovered by the Wide-field Infrared Survey Explorer satellite, see Comet WISE and NEOWISE.

C/2016 U₁ (NEOWISE) is a hyperbolic comet discovered 21 October 2016 by NEOWISE, the asteroid-and-comet-hunting portion of the Wide-Field Infrared Survey Explorer (WISE) mission.^[1][2][3] The comet brightened to magnitude +6.8^[4] and could be observed with binoculars,^[5] during the first week of 2017 and it was closest to the Sun on 14 January 2017.^[2][6]

C/2016 U₁ (NEOWISE)

Discovery
Discovered by	NEOWISE project
Discovery site	NEOWISE
Discovery date	Friday 21 October 2016[1]
Orbital characteristics
Epoch	2457723.5 (2016-Dec-01.0) TDB[1] Reference: JPL 4 (heliocentric ecliptic J2000)[1]
Perihelion	0.3191 AU[1]
Semi-major axis	−3477.5728 AU[1]
Eccentricity	1.0001[1]
Inclination	46.4292 deg[1]
Longitude of ascending node	61.4214 deg[1]
Argument of periapsis	162.7640 deg[1]
Last perihelion	14 January 2017
Next perihelion	ejection
Comet total magnitude (M1)	13.7[1]
Comet nuclear magnitude (M2)	20.0[1]

It was closest to the Earth on 13 December 2016 at 106,000,000 km (66,000,000 mi)^[5] away; it is not considered a threat to Earth.^[2] The aphelion of the comet lies at the inner edge of the Oort cloud and it is possible that the 2017 perihelion was not the first and that during a previous perihelion planetary perturbations pushed the comet towards the Oort cloud. Despite its small size, the comet survived perihelion and was observed for days from the SWAN instrument on board SOHO.^[7]

Orbit of C/2016 U₁ (NEOWISE) on 14 January 2017, closest approach to the Sun.^[1][3]