C/2000 U5 (LINEAR)
Discovered byLINEAR 1.0-m reflector (704)[1]
Discovery dateOctober 29, 2000
Orbital characteristics A
EpochDecember 15, 2000
(JD 2451893.5)
Aphelion5600 AU (inbound)[2]
N/A (outbound)
Perihelion3.4861 AU (q)
Semi-major axis−652.38 AU[3][a]
1.0057 (epoch 2008+)[2]
Orbital period~150000 years (inbound)[2]
ejection (outbound)
Last perihelionMarch 13, 2000[3]
Next perihelionejection

C/2000 U5 (LINEAR) is a single-apparition comet discovered on October 29, 2000, by Lincoln Near-Earth Asteroid Research.[1] The comet has an observation arc of 362 days[3] allowing a good estimate of the orbit. C/2000 U5 is, as of 2015, the 13th most hyperbolic comet ever discovered and will leave the Solar System.

Before entering the inner Solar System for a 2000 perihelion passage, C/2000 U5 had a barycentric (epoch 1950-Jan-01) orbit with an apoapsis distance of about 5,600 AU (0.09 ly), and a period of approximately 150,000 years.[2]

The comet came to perihelion on March 13, 2000.[3] As the comet was leaving the inner Solar System, it passed within 0.766 AU of Jupiter on February 3, 2001,[4] Since an epoch of 2000-Dec-06, C/2000 U5 has had a barycentric eccentricity greater than 1,[2] keeping it on a hyperbolic trajectory that will eject it from the Solar System.

The escape velocity from the Sun at Neptune's orbit is 7.7 km/s. By May 2014, the comet was passing Neptune's orbit at 30.1 AU from the Sun continuing its ejection trajectory at 7.8 km/s.[5] In 2029, when it is more than 50 AU from the Sun and beyond the influence of the planets, it will still have a barycentric eccentricity of 1.0057.[2]

Comet C/1980 E1 has an even greater eccentricity.


  1. ^ C/2000 U5 is on an escape trajectory out of the Solar System, i.e. it has a hyperbolic orbit. For a hyperbolic orbit the semi-major axis is still defined, but is negative. This value cannot be interpreted as average distance from the Sun. The orbital energy is inversely proportional to negative semi-major axis. Objects in hyperbolic orbits have negative semi-major axis, giving them a positive orbital energy.


  1. ^ a b Brian G. Marsden (2000-11-01). "MPEC 2000-V02 : COMET C/2000 U5 (LINEAR)". IAU Minor Planet Center. Retrieved 2011-03-12.
  2. ^ a b c d e f Horizons output. "Barycentric Osculating Orbital Elements for Comet C/2000 U5 (LINEAR)". Solution using the Solar System Barycenter. Ephemeris Type:Elements and Center:@0 (To be outside planetary region, inbound epoch 1950 and outbound epoch 2050)
  3. ^ a b c d e "JPL Small-Body Database Browser: C/2000 U5 (LINEAR)" (last observation: 2001-10-26; arc: 362 days). Jet Propulsion Laboratory. Retrieved 2011-03-12.
  4. ^ "JPL Close-Approach Data: C/2000 U5 (LINEAR)" (last observation: 2001-10-26; arc: 362 days). Retrieved 2010-03-12.
  5. ^ "Horizons Batch: Passing Neptune's orbit at 30.1 AU from the Sun" (Solar escape velocity at 30.1 AU is about 7.67 km/s). JPL Horizons.