Sky spectacle in November: How bright will Comet Leonard be?

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Astronomy highlight in winter: Comet Leonard (C / 2021 A1) could be visible to the naked eye in November and December. What you need to know

Frankfurt – A comet that can be seen in the sky with the naked eye does not occur often. In recent years there has only been one comet that halfway falls into this category: Comet Neowise (C / 2020 F3) was visible to the naked eye for some time in the summer of 2020 and under very dark skies. But there could be a successor soon: Komet Leonard (C/2021 A1) is currently being watched closely by astronomers – it has the potential to become bright enough. But you shouldn’t rejoice too soon – because the behavior of comets is very difficult to assess.

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 Lemmon Observatory in Tucson, Arizona. At that time, the comet was about 750 million kilometers from the sun. On January 3, 2022, its trajectory will be closest to the Sun, known as perihelion. Leonard is then about 92.2 million kilometers from the sun. It already has its closest approach to Earth: The US space agency NASA estimates that Comet Leonard will come closest to Earth on December 12, 2021 at around 2:54 p.m. German time – at a safe distance of almost 35 million kilometers.

Comet Leonard (C / 2021 A1) could be visible to the naked eye in November / December 2021

How bright Comet Leonard will be in November and December 2021 will only show with time. According to estimates by the “EarthSky” portal, a brightness between magnitude 5 and 2.6 is assumed. The lower this value, the brighter the object can be seen. But the behavior of comets is generally considered to be unpredictable, which makes it very difficult to predict how the brightness of Comet Leonard will develop. The comet Atlas, for example, was considered a bearer of hope in 2020 – and broke up before it could put on a show in the sky. Something similar happened to Comet Ison in 2013, which broke on its closest approach to the Sun.

Name C/2021 A1 Leonard
Celestial bodies Comet
discovery January 3, 2021 by Greg J. Leonard
Perihelion (closest approach to the sun) 0.6151 AU am 3.01.2022
Closest approach to earth 0.233 AU am 12.12.2021

How to find Comet Leonard in the night sky

Should Comet Leonard become visible to the naked eye, it will first be seen in the northern hemisphere, and later in the southern hemisphere. The comet is traveling at a speed of 254,412 kilometers per hour – but you will not see it “racing” across the sky, as Leonard is very far from Earth. One thing is certain: if you want to see the comet in the sky, you have to look out for it early in the morning. Around the middle of November, Comet Leonard wanders into the constellation “Haar der Berenike”, which rises at around 1.30 a.m. in the east. On December 2nd, the comet can be seen very close to the globular cluster M3, and then moves on towards the bright star Arctur in the constellation “Bear Guardian”.

The specialist magazine “Sky & Telescope” estimates that the comet could reach a magnitude of 10 in mid-November – a brightness that cannot yet be seen with the naked eye, but can already be seen with smaller telescopes. Around the time that Comet Leonard is near the star Arcturus, it could reach a magnitude of 5.5 and thus become an object that can be faintly perceived with the naked eye. In the northern hemisphere, you can catch the last glimpse of the comet in the morning sky on December 12, 2021 – shortly before its theoretically greatest brightness. It will then be visible low in the southwestern sky at dusk. Observers in the southern hemisphere now also have the opportunity to take a look at the comet.

Comets are “dirty snowballs” from the depths of space

Comets come from the depths of space and consist of dust and rock that is held together by ice. When a comet gets closer to the sun, the ice melts and dust and stones are released – the characteristic comet’s tail is created. This is exactly what makes predicting the brightness of Comet Leonard (C / 2021 A1) so difficult: Nobody can predict exactly how the comet will behave in the rising heat – it will become more active, but how active? Nobody can reliably predict that at the moment.

Comets – nickname: “Cosmic Snowballs” – are particularly interesting for research because they are considered to be messengers from the depths of the universe. According to NASA calculations, Comet Leonard comes from the outer solar system and has been moving over 550 billion kilometers towards the center of the solar system for 40,000 years. After he has reached his perihelion, according to NASA, he will probably be thrown out of the solar system. So winter 2021/2022 is the last chance to see Comet Leonard.

Only recently, two researchers accidentally discovered the largest comet known to date. It is on the way towards the center of the solar system, in 2031 it should reach its point closest to the sun. (tab)

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Sky spectacle in November: How bright will Comet Leonard be?

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