C/1980 E1 is a non-periodic comet discovered by Edward L. G. Bowell on 11 February 1980 and which came closest to the Sun (perihelion) in March 1982. It is leaving the Solar System on a hyperbolic trajectory due to a close approach to Jupiter. In the 43 years since its discovery only two objects with higher eccentricities have been identified, 1I/ʻOumuamua (1.2) and 2I/Borisov (3.35).[3][4]
Before entering the inner Solar System for a 1982 perihelion passage, C/1980 E1 had a barycentric (epoch 1950-Jan-01) orbit with an aphelion of 75,000 AU (1.2 ly), and a period of approximately 7.1 million years.[1]
As the comet was approaching on 9 December 1980, it passed within 0.228 AUofJupiter,[2] which accelerated the comet briefly giving an (epoch 1981-Jan-09) eccentricity of 1.066.[1] The comet came to perihelion on 12 March 1982,[2] when it had a velocity of 23.3 km/s (52,000 mph) with respect to the Sun. Since the epoch of 1977-Mar-04, C/1980 E1 has had a barycentric eccentricity greater than 1,[1] keeping it on a hyperbolic trajectory that will eject it from the Solar System. Objects in hyperbolic orbits have a negative semimajor axis, giving them a positive orbital energy. After leaving the Solar System, C/1980 E1 will have an interstellar velocity () of 3.77 km/s.[a] The Minor Planet Center does not directly list a semimajor axis for this comet.[5]
The escape velocity from the Sun at Neptune's orbit is 7.7 km/s. By June 1995, the comet was passing Neptune's orbit at 30.1 AU from the Sun continuing its ejection trajectory at 8.6 km/s.[6] Since February 2008, the comet has been more than 50 AU from the Sun.[7]
C/1980 E1 distance and velocity compared to the Sun with a 300 year stepsize[8]
Emission of OH (hydroxide) was observed pre-perihelion while the comet was nearly 5 AU from the Sun.[9] CN (cyanide) was not detected until the comet was near perihelion. The comet nucleus was estimated to have a radius of several kilometers. The surface crust was probably a few meters thick.
Eccentricity vs timeAnimation of C/1980 E1's orbit C/1980 E1 (Bowell)· Sun·· Earth· Mars· Jupiter· Saturn
^v = 42.1219 √1/r − 0.5/a, where r is the distance from the Sun, and a is the major semi-axis. At epoch 2500, C/1980 E1 will have a barycentric semi-major axis of −62.44.
