C/2021 A1 (Leonard)—discovered at Arizona’s Mount Lemmon Observatory on January 3, 2021 by Greg Leonard, a senior research specialist—will reach its perihelio (closest approach to the Sun) on January 3, 2022.
How and when to see Comet Leonard
Comet Leonard will pass closest to Earth on December 12, 2021 when it gets just a fifth of the distance from the Earth to the Sun to create a well-timed “Christmas Comet.”
It won’t pose any danger and it may become visible to the naked eye around that time. If so, it will be visible close to bright star Arcturus in the constellation of Boötes just before sunrise and just after sunset. If not naked-eye, then binoculars should give a great view. Here’s where Comet Leonard is right now.
However, Comet Leonard is going to do something unusual less than a week later.
Comet Leonard ‘grazes’ Venus
A paper has just been published that describes how close Comet Leonard will get to Venus—and it’s really close!
On December 18, 2021, the authors predict that Comet Leonard will pass just 2.6 million miles/4.3 million kilometers from the second planet from the Sun. It will then graze Venus with its dust trail less than two days later.
It’s the closest known incident of a long period comet coming so close to any planet save for the 2014 encounter of Comet C/2013 A1 Siding Spring and Mars, which produced a meteor shower on the red planet that could be seen by NASA spacecraft.
Observing the comet using the Lowell Discovery Telescope in Arizona and the Palomar Hale Telescope in California, the authors think the close call poses negligible risk to any spacecraft in orbit around Venus—specifically Japan’s Akatsuki orbiter.
Although it’s thought unlikely that the pass could cause a meteor shower on Venus, the authors suggest that it will be a good opportunity to study an otherwise unseen dust trail from a comet never before studied as close.
Found: another new comet
Just reported is a new possibly bright comet called C/2021 O3 (PanSTARRS). Seen for the first time in late July by a 71-inch PanSTARRS sky survey telescope at Haleakala Observatory in Hawaii, “O3” is in the constellation of Pegasus—the “great Square: thats now visible in high in the east after dark.
“O3” is destined to become a visible comet—either through binoculars or possibly naked-eye—in early May, 2022.
What about the ‘mega-comet?’
Both Comet Leonard and Comet O3 are dwarfed by a comet called C/2014 UN271 (Bernardinelli-Bernstein)—or more simply Comet Bernardinelli-Bernstein—a long-period comet of unknown origin and the biggest ever seen—which will get closest to the Sun in 2031.
Wishing you clear skies and bright eyes.