A little ramble through Corona Australis the Southern Crown

Corona Australis the Southern Crown is a counterpart in the southern hemisphere for the Northern Crown of Corona Borealis in the northern hemisphere.

In appearance it looks like a curve of faint stars which is easily recognisable, however it is not visible from Britain. In modern maps it can be found just below the teapot asterism in Sagittarius.

Although faint it is recognised as one of the original 48 Greek constellations. Ptolemy recorded it around 150CE and called it The Southern Wreath, while earlier around 130 BCE Hipparchus on his star chart saw the group as The Caduceus or Herald’s Wand of Peace.

The Arab astronomer Al Sufi in 964 CE produced a star map and on his chart the group was known as Al Kubbah or the Tortoise, another Arab astronomer al Kazwini called it Al Udha al Na’am or The Ostrich’s Nest. While the Chinese astronomers also saw the group as a Tortoise.

As none of the stars are very bright, I will only mention alpha and beta, both have a magnitude or brightness of 4.1 meaning of course that any mist or moonlight will; make them very difficult to see.

Alpha is an A class star hotter than our Sun and lies at a distance of 150 light years, whereas Beta is a K class giant star cooler than the Sun and is 508 light years away.

There are no messier objects in Corona Australis but there is the Corona Australis Molecular Cloud which can be found just north of the star beta and at around 430 light years away is one of the closest star forming areas in the galaxy to us. There are over 7,000 proto stars in this region plus many other very young stars here. The whole structure covers around 66 light years.

The cloud is not bright enough to be seen with the naked eye,  a large telescope is needed to see it.

 

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