| C/2023 E1 (ATLAS) | |
| Discovery Ref: | [1] |
| Discoverer: | ATLAS |
| Discovery Date: | 1 March 2023 |
| Orbit Ref: | [2] |
| Epoch: | 25 May 2023 |
| Observation Arc: | 214 days |
| Earliest Precovery Date: | 25 December 2022 |
| Aphelion: | 37.660 AU |
| Perihelion: | 1.027 AU |
| Semimajor: | 19.343 AU |
| Eccentricity: | 0.947 |
| Period: | 85.07 years |
| Inclination: | 38.313° |
| Asc Node: | 164.57° |
| Arg Peri: | 105.89° |
| Earth Moid: | 0.365 AU |
| M1: | 16.1 |
| M2: | 18.3 |
| Last P: | 1 July 2023 |
C/2023 E1 (ATLAS) is a periodic comet with an orbital period of 85 years. It fits the classical definition of a Halley-type comet with an orbital period of between 20 and 200 years. The comet was discovered on 1 March 2023 by ATLAS South Africa. Upon discovery, the comet had an apparent magnitude of about 19 and had a very condensed coma. The comet was subsequently found in images obtained by other observatories back on 25 December 2022.[1] [3]
The comet brightened in late June to a magnitude of +10, and became visible in small telescopes and binoculars. At that time, it was located high in the northern skies, in the constellation of Ursa Minor. It passed its perihelion on 1 July and reached an apparent magnitude between 8 and 9.[4] [5] The comet had a greenish coma and a faint narrow ion tail.[6] On July 8 it passed 9 degrees from the north celestial pole. The closest approach to Earth was on 18 August, at a distance of 0.375 AU.[7]
The comet seems to be in a 2:1 orbital resonance with Neptune, with the comet completing two orbits for every orbit Neptune does.[7]