Winter astronomical highlight: Comet Leonard (C/2021 A1) is visible to the naked eye in November and December. What you need to know
Frankfurt – comets that can be seen in the sky with the naked eye are not very common. In recent years, only one comet has fallen into this category: Comet Neues (C/2020 F3) is visible to the naked eye for some time in the summer of 2020 and under very dark skies. But maybe there will be a replacement soon: Komet Leonard (C/2021 A1) Astronomers are currently watching it closely – it will likely become quite bright. But you should not rejoice early – because it is very difficult to judge the behavior of comets.
Comet Leonard was the first comet to be discovered in 2021: it was first spotted on January 3, 2021, by astronomer Greg J. Leonard at the Mount Lemon Observatory in Tucson, Arizona. At that time, the comet was about 750 million kilometers from the Sun. On January 3, 2022, its orbit will be closest to the Sun, known as perihelion. Then Leonard is about 92.2 million km from the Sun. It already has its closest approach to Earth: NASA predicts that Comet Leonard will approach Earth on December 12, 2021, at around 2:54 p.m. German time — at a safe distance of about 35 million km.
c / 2021 a 1 leonard 2021 nov. 7 Output 3,38 5×4 menit 11″ RACE Nikon Z6mod Michael Jäger pic.twitter.com/nNWiIIbteK
– Michael Jager (@Komet123Jager) 7 November 2021
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Comet Leonard (C/2021 A1) is visible to the naked eye in November/December 2021
Comet Leonard’s brightness will appear in November and December 2021 as time goes on. According to estimates by the “EarthSky” portal, the brightness is assumed to be between 5 and 2.6. The lower this value, the brighter the object can be seen. But comet behavior is generally considered unpredictable, which makes it very difficult to predict how comet Leonard’s brightness will develop. For example, Comet Atlas was considered the hope for 2020 – and it broke before it had time to appear in the sky. Something similar happened to Comet Ison in 2013, which broke up on its closest approach to the sun.
| Nouns | C / 2021 A1 Leonard |
| spiral star | comet |
| Invention | January 3, 2021 By Greg J. Leonard |
| perihelion (closest approach to the sun) | 0.6151 AU morning 3.01.2022 |
| Closest approach to Earth | 0.233 AU at 12.12.2021 |
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How to find Leonard’s Comet in the night sky
If Comet Leonard were visible to the naked eye, it would be visible first in the Northern Hemisphere, and then in the Southern Hemisphere. The comet is moving at 254,412 kilometers per hour – but you won’t see it “race” through the sky, because Leonard is so far from Earth. One thing is for sure: if you want to see a comet in the sky, you have to look for it in the morning. Around mid-November, Comet Leonard wanders through the constellation “Haar der Berenike,” which rises at about 1.30 am in the east. On December 2, the comet could be seen near the globular cluster M3, and then moved toward the bright star Arctur in the constellation “Bear Guardian”.
Special magazine “Sky & Telescope” estimates that the comet could reach 10 degrees by mid-November – a brightness that cannot be seen with the naked eye, but can already be seen with smaller telescopes. About the time Comet Leonard is near the star Arcturus, it can reach a magnitude of 5.5 degrees and thus become something that can be seen with the naked eye. In the Northern Hemisphere, you can catch a glimpse of the comet in the morning sky on December 12, 2021 — just before its theoretical maximum brightness. It will then look low in the southwest sky at dusk. Observers in the southern hemisphere now have the opportunity to see the comet.
Comets are “dirty snowballs” from the depths of outer space
Comets come from the depths of space and consist of dust and rock held together by ice. When a comet approaches the Sun, the ice melts and dust and rock are released – the comet’s characteristic tail is formed. This is precisely what makes predictions of the brightness of Comet Leonard (C/2021 A1) so difficult: no one can predict exactly how the comet will behave in increasing heat – it will become more energetic, but how active? No one can reliably expect that at this time.
Comets – nicknames: “cosmic snowballs” – are very interesting to study because they are considered messengers from the depths of the universe. According to NASA calculations, Comet Leonard originated in the outer solar system and moved more than 550 billion km towards the center of the solar system 40,000 years ago. Once it reaches perihelion, according to NASA, it will likely be ejected from the solar system. So winter 2021/22 is your last chance to see Comet Leonard.
Recently, two researchers accidentally discovered the largest comet known to date. It is on its way to the center of the solar system, in 2031 it will reach its closest point to the sun. (tab)
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