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 3 objects with higher eccentricities have been identified, 1I/ʻOumuamua (1.2), 2I/Borisov (3.35), and 3I/ATLAS (6.15).
Overview 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 , and a period of approximately 7.1 million years.
As the comet was approaching on 9 December 1980, it passed within 0.228 AU of Jupiter, which accelerated the comet briefly giving an (epoch 1981-Jan-09) eccentricity of 1.066. The comet came to perihelion on 12 March 1982, when it had a velocity of with respect to the Sun. Since the epoch of 1977-Mar-04, C/1980 E1 has had a barycentric eccentricity greater than 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. The Minor Planet Center does not directly list a semimajor axis for this comet. On 24 January 2022, C/2024 L5 (ATLAS) had a similar episode with Saturn, resulting in its ejection from the Solar System.
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. Since February 2008, the comet has been more than 50 AU from the Sun.
+C/1980 E1 distance and velocity compared to the Sun with a 300-year stepsize Date Sun distance(AU) Velocitywrt Sun(km/s) Uncertaintyregion(3-sigma) 1682-03-12 2.68 ± 7 million km Perihelion 23.3 ± 1589 km 2282-03-12 4.43 ± 5 million km
Emission of OH (hydroxide) was observed pre-perihelion while the comet was nearly 5 AU from the Sun. 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.
See also List of Solar System objects by greatest aphelion List of hyperbolic comets List of non-periodic comets List of periodic comets 1I/ʻOumuamua 2I/Borisov 3I/ATLAS C/2024 L5 (ATLAS)
Notes
References Solution using the Solar System Barycenter. Ephemeris Type:Elements and Center:@0 (To be outside planetary region, inbound epoch 1950 and outbound epoch 2050)
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