C/2000 W1 (Utsunomiya–Jones)

C/2000 W1 (Utsunomiya–Jones) is a long-period comet from the Oort cloud discovered on November 18, 2000, by Syogo Utsunomiya and Albert F. A. L. Jones.^[1] The comet reached up to apparent magnitude 5.5,^[5][6] but was only 27 degrees from the Sun in mid-December 2000.^[7]

C/2000 W1 (Utsunomiya–Jones)

Discovery
Discovered by	Syogo Utsunomiya Albert F. A. L. Jones[1]
Discovery date	November 18, 2000
Orbital characteristics
Observation arc	58 days
Number of observations	440
Aphelion	~70,000 AU (inbound) ~1670 AU (outbound)[2]
Perihelion	0.32118 AU (q)
Semi-major axis	~35,000 AU (inbound) ~835 AU (outbound)[2]
Eccentricity	0.9999996[3]
Orbital period	millions of years (inbound) ~24,000 yr (outbound, if it survived)[2]
Max. orbital speed	74.3 km/s (166,000 mph)[4]
Inclination	160.16°
Last perihelion	December 26, 2000[3]

The comet has an observation arc of 58 days allowing a reasonable estimate of the orbit. Though the near-perihelion orbit solution shows the comet to be on a hyperbolic trajectory,^[3] the orbit of a long-period comet is properly obtained when the osculating orbit is computed at an epoch after leaving the planetary region and is calculated with respect to the center of mass of the Solar System. Using JPL Horizons, the barycentric orbital elements for epoch 2020-Jan-01 generate a semi-major axis of 835 AU, an aphelion distance of 1670 AU, and a period of approximately 24,000 years.^[2]

C/2000 W1 came to perihelion on 26 December 2000 when it passed 0.321 AU (48.0 million km; 29.8 million mi; 125 LD) from the Sun.^[3] It was last observed in February–March 2001 when it faded suddenly and probably disintegrated.^[8][9]