Comet Leonard - the view from La Perouse


Sydney City Skywatcher member George Mavrocordatos has imaged Comet Leonard:


I managed to be lucky enough to take my own picture of Comet Leonard at La Perouse on Xmas Eve. Somehow the clouds cleared and I managed to point the camera to the correct spot even though I couldn't see it.

I'm happy about this, its a great Christmas present, George.

Comet Leonard - known by astronomers as C/2021 A1 (Leonard), was observed in January 2021 by astronomer Greg Leonard at the Mount Lemmon observatory in Arizona. This comet is really really large and moving fast but don't worry Comet Leonard is not going to cause a catastrophic event - this is not the movie 'Look Up' which is currently trending on Netflix. This comet's orbit is around the outer areas of our solar system.


There are still a few days left to see the comet if the sky is clear, start looking about two hours after sunset.


Every year a few comets are 'discovered' or re-discovered and named after the discoverer, or I like to say modern observer, because some of these comets have been past Earth before and would have been observed earlier but not always recorded. For example Halleys Comet was named after astronomer Edmund Halley who predicted the comets return but actually never saw it, but we know the Ancient Greeks saw it and it is likely First Nations Peoples were the first to observe Halleys Comet. Halleys Comet orbit means it returns every 75 years and its next return will be in 2061.


What is a Comet?

A comet is often referred to as a 'dirty snowball' and this is because it is composed of rocks, dust and ice. It has a nucleus, coma, tail and is surrounded by a hydrogen-hydroxyl cloud. Comets travel in an orbit in our solar system and travel in an orbit around the Sun as they are subject to the forces of gravity and other forces, their composition is complex. They have been researched and theorised over for centuries using increasingly sophisticated techniques. There were breakthroughs in our understanding of comets in theb1880s when astronomers used spectroscopes to identify the sodium, carbon and iron. Then in the early 1900s nickel and ionized carbon monoxide were identified, it was also shown that comets differ in their composition. By the late 20th century we knew that comets had an abundance of H2O - water as ice crystals and this makes up most of the nucleus, that comets have two tails, an ice tail and a gas tail and that comets are surrounded by a large hydrogen 'cloud'.


NASA has been exploring comets for decades and in 2011 comet Tempel was studied by the Deep Impact Mission.

Take a minute to read more fun comet information in our Did you know? blog.


REFERENCES:

Brandt J, Chapman R, 1981, Introduction to Comets.

NASA website: https://www.nasa.gov/image-feature/goddard/2021/views-of-comet-leonard-from-two-sun-watching-spacecraft

Space. com : https://www.space.com/comet-leonard-discovery-explained-interview

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