Lexell's Comet

[12] The comet was discovered on June 14, 1770, in the constellation Sagittarius by Messier, who had just completed an observation of Jupiter and was examining several nebulae.

[13] It was observed in the Hejaz in Safar 1184 AH (June 1770), where some believed it to be the comet predicted by the poet al-Fasi, portending future events.

[14][15] On July 1, 1770, the comet passed 0.015 astronomical units from Earth,[9] or approximately 6 times the radius of the Moon's orbit.

[18] After conducting further work in cooperation with Pierre-Simon Laplace, Lexell argued that a subsequent interaction with Jupiter in July 1779[19] had further perturbed its orbit, either placing it too far from Earth to be seen or perhaps ejecting it from the Solar System altogether.

[20] He showed that after the second encounter with Jupiter many different trajectories were possible, given the uncertainties of the observations, and the comet could even have been ejected from the Solar System.

[23] In a 2018 paper, Quan-Zhi Ye et al. used recorded observations of the comet to recalculate the orbit, finding Le Verrier's 1844 calculations to be highly accurate.

The numbers remain consistent even when including non-gravitational parameters caused by pressures from a comet's jets.

Additionally, based on a lack of meteor showers, they suggest that the comet may have ceased major activity before 1800.

[2] They find that 2010 JL33 is very likely to be a remnant of Lexell's comet, although due to a number of close approaches with Jupiter as well as uncertain non-gravitational parameters, a definite link cannot be made.