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Apus

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Apus is a small constellation located in the southern sky. It represents the bird-of-paradise, a beautiful bird from far away. Its name comes from the Greek word "apous," which means "without feet."

BayerUran1661apuschamtri
BayerUran1661apuschamtri

This name came from an old mistake made by people in the West. When birds arrived in Europe in 1522, their feet had been removed. Because of this, people wrongly believed the birds had no feet at all. Today, the constellation covers about 0.5% of the entire sky.

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Potw1431a

The stars in Apus have very interesting ways they work. The five brightest stars are all reddish in color. This is unusual for a group of stars. One star, Alpha Apodis, is an orange giant star. It used to be a blue-white star. As it used up its core hydrogen, it began to expand and cool down.

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Now, it is 48 times wider than our Sun. It also shines with 928 times the luminosity, or brightness, of our Sun. This shows how stars change as they grow older.

Humans have been mapping this part of the sky for a long time. Petrus Plancius first put Apus on a celestial globe in 1598. He used observations from explorers named Pieter Dirkszoon Keyser and Frederick de Houtman. These men sailed on a Dutch trading trip to the East Indies.

BayerUran1661apuschamtri
BayerUran1661apuschamtri

In 1603, Johann Bayer included the constellation in his famous star atlas. Later, in 1756, Nicolas Louis de Lacaille charted the brighter stars. He gave them the special names we use today. He even used some of these stars to help create the constellation Octans.

There are many specific details to find in this constellation. Alpha Apodis is about 430 light-years away from Earth. Another star, Delta Apodis, is a double star. This means it is actually two stars that are 103 arcseconds apart. You can even see these two stars with your naked eye.

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Potw1431a

Some stars even have planets orbiting them. The star HD 134606 has three planets. These planets orbit at different times, like 12 or 59.5 days. Another star, HD 137388, has a planet that is 79 times as massive as Earth.

Apus connects to the bigger picture of our galaxy. The Milky Way galaxy covers much of this area of the sky. You can find large groups of stars called globular clusters here. One cluster is named NGC 6101 and is 50,000 light-years away.

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This cluster is very old, at about 13 billion years. It contains bright stars called blue stragglers. These stars are thought to be made when two stars merge together. Looking at Apus helps us see how stars and galaxies grow and change.

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