Winter astronomy highlights: Comet Leonard (C/2021 A1) may be visible to the naked eye in November and December. what do you want to know

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

Comet Leonard was the first comet to be discovered in 2021: it was first discovered on January 3, 2021, by astronomer Greg J. Leonard observed at Mount Lemmon Observatory in Tucson, Arizona. At that time the comet was at a distance of 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’s already closest to Earth: 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 about 35 million kilometers.

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

Only time will know how bright Comet Leonard will be in November and December 2021. According to estimates from the “Earthsky” portal, a brightness between magnitude 5 and 2.6 is thought to be. The lower this value, the brighter the object will appear. But the behavior of comets is generally thought to be unpredictable, making it very difficult to predict how Comet Leonard’s brightness will develop. Comet Atlas, for example, was thought to be a bearer of hope in 2020—and broke up before it came to a show in the sky. Something similar happened with Comet Ison in 2013, which broke up when it came closest to the Sun.

How to Spot Comet Leonard in the Night Sky

If Comet Leonard becomes visible to the naked eye, it will be seen first in the Northern Hemisphere and later in the Southern Hemisphere. The comet is traveling at 254,412 kilometers per hour – but you won’t see it “racing” across the sky, because Leonard is so far away from Earth. One thing is certain: if you want to see a comet in the sky, you have to look for it early in the morning. Around mid-November, Comet Leonard orbits in the constellation “Haar der Berenice”, rising in the east at about 1.30 p.m. On December 2, the comet can be seen very close to the globular cluster M3, and then moves to Arctur, the bright star in the constellation “Bear Guardian”.

The specialist magazine “Sky & Telescope” estimates that the comet may 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 can reach a magnitude of 5.5 and thus become an object that can be seen with the naked eye. In the Northern Hemisphere, you can see the comet’s last glimpse in the morning sky on December 12, 2021—shortly before theoretically its greatest brightness. It will be less visible in the southwest sky in the evening. Southern Hemisphere observers now also have the opportunity to get a closer 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 held together by ice. When a comet approaches the Sun, the ice melts and the dust and stones are released – forming the tail of the comet. This is what makes it so difficult to predict the brightness of Comet Leonard (C/2021A1): no one can predict how the comet will behave in the increasing heat – it will become more active, but how active? At the moment no one can predict it with certainty.

Comets – nicknamed: “cosmic snowballs” – are of particular interest to research because they are considered messengers from the depths of the universe. According to NASA calculations, Comet Leonard comes from the outer Solar System and has been moving toward the center of the Solar System more than 550 billion kilometers over 40,000 years. According to NASA, when it has reached its perihelion, it will likely be ejected from the Solar System. So winter 2021/2022 is the last chance to see Comet Leonard.

Recently, two researchers accidentally discovered the largest comet ever known. It is heading towards the center of the solar system, reaching its closest point to the Sun in 2031. (tab)