Comet C/2021 A1 (Leonard)
C/2021 A1 (Leonard) was discovered on 3 January 2021 by Greg Leonard, a senior research specialist with the Catalina Sky Survey at the University of Arizona's Lunar & Planetary Laboratory.
| Orbital Elements Date | 22 November 2021 |
|---|---|
| eccentricity | 1.0001 |
| inclination | 132.7° |
| semi-major axis | −6589.2 au (hyperbolic) |
| period | none (hyperbolic) |
| perihelion distance | 0.6152 au |
| perihelion date | 3 January 2022 |
| distance from Earth at closest approach | 0.2302 au |
| date of closest approach to Earth | 12 December 2021 |
The Minor Planet Center (MPC) estimates that the comet may reach fourth magnitude around the time of closest approach to Earth but the Jet Propulsion Laboratory (JPL) is far more pessimistic with a prediction of just eighth magnitude. The comet is in Coma Berenices at the beginning of December but soon moves into Boötes, passing near first-magnitude star Arcturus on 6 December. It continues southward and should be at its brightest as it moves through Ophiuchus, Serpens and Scutum. Mid-month finds the comet in Sagittarius, with perihelion in January taking place in the southern constellation of Piscis Austrinus.
At the beginning of December, the comet is visible to northern hemisphere observers in both the morning and evening skies, but it should be easier to observe before sunrise. It begins to fade from mid-December so those in the southern hemisphere will not get quite as good of a view when it passes through the more southerly constellations in late December and early January.
