Comet Messier–Méchain, also known as C/1785 A1 from its modern nomenclature, is a faint parabolic comet that was observed several times by French astronomers, Charles Messier and Pierre Méchain, in January 1785.
Discovery and observations
Charles Messier discovered this comet using a small refractor following an observation of Uranus on the night of 7 January 1785.[1] Approximately 40 minutes later, Pierre Méchain also discovered the same comet from the Paris Observatory.[4] At the time, the comet was located within the constellation Cetus.[a]
Messier described the comet as a faint object surrounded by a "central condensation" around it, where he also noted that it became brighter on 9 January than it was two days earlier, but it never became visible to the naked eye.[4] He continued to observe the comet until 17 January 1785, when it was no longer visible near the star ε Cet.[5]
Orbit
The only known orbital calculations of the comet were written by Méchain in 1788, where he determined a parabolic trajectory that indicated the comet had reached perihelion on 27 January, while making its closest approach to Earth a day later at a distance of 0.417 AU (62.4 million km)[4]
In 2012, Maik Meyer noted that the preliminary orbital calculations for the comet C/2012 L2 (LINEAR) were strikingly similar to that of Messier–Méchain, however he concluded that this is only a coincidence rather than a return of C/1785 A1 itself.[6]
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