Piscis Austrinus

Look at the stars.

They make a big fish. This is the southern fish. One star is very bright. It is the 18th brightest star in the sky. This bright star is named Fomalhaut. It is much bigger than our Sun. This fish is in the southern sky. Some people say it swallows water. It is a very special part of the stars.

Piscis Austrinus is a group of stars in the southern sky. Its name is Latin for "the southern fish."

Long ago, people in Babylon saw this pattern as a fish. Ancient Greeks also knew it. They called it the Great Fish. In their stories, the fish swallows water from the constellation Aquarius.

Most stars in this group are dim. However, one star shines very bright. It is named Fomalhaut. It is the 18th brightest star in the night sky. Fomalhaut is a white star. It is much bigger and brighter than our Sun. It also has a ring of dust around it.

There are other things to find here. One star is a red dwarf named Lacaille 9352. It is very close to us. It is only 10.74 light-years away. But it is too faint to see without a telescope. Scientists have also found many exoplanets here. These are planets that orbit other stars. Some of these stars have planets like Jupiter. Others have planets like the Earth.

Piscis Austrinus is a group of stars in the southern sky. Its name is Latin for "the southern fish."

This constellation is one of the 88 modern groups of stars. It is also a faint constellation. Most of its stars are hard to see. Only one star shines brightly enough for the naked eye. This star is named Fomalhaut. It is the 18th brightest star in the whole night sky.

Fomalhaut is a white star that is very special. It is much bigger and brighter than our Sun. It is about 1.92 times as massive as the Sun. It is also 16.63 times as bright. Fomalhaut is about 25.13 light-years away from Earth. Scientists found a ring of dust around this star. They once thought they saw a planet there called Fomalhaut b. Later, they found it was actually a large cloud of dust. Other stars in this group also have unique ways of working. For example, Delta Piscis Austrini is a star that burns helium in its core.

Many people have studied these stars for a long time. The astronomer Ptolemy listed this constellation in the 2nd century. He called it Ichthus Notios. Later, German mapmakers used different Latin names for it. The English astronomer John Flamsteed used the name Piscis Austrinus. This is the name we use most often today. In 1922, the International Astronomical Union gave it the short name "PsA." In 1930, an astronomer named Eugène Delporte set the official borders for the group. These borders form a shape with four straight segments.

There are many interesting objects inside these star borders. One star is a red dwarf named Lacaille 9352. It is only 10.74 light-years away from us. Even though it is close, it is too dim to see without a telescope. Scientists have found many exoplanets, or planets around other stars, here. For example, the star HD 205739 has a planet much bigger than Jupiter. The star HD 216770 has a planet that orbits every 118 days. There are even far-away galaxies in this area. These include NGC 7172, NGC 7174, and NGC 7314.

This constellation connects to many old stories from Earth. It began with the Babylonians, who called it "the Fish." The ancient Greeks called it the Great Fish. They told stories of the fish swallowing water from Aquarius. In Egypt, people believed this fish saved the goddess Isis. Because of this, they put the fish in the stars. In Syria, people thought fish were sacred because of these old tales. Today, we look at these same stars to learn about space. We can see them if we are south of 53 degrees North latitude.

Piscis Austrinus is a constellation located in the southern celestial hemisphere. Its name is Latin for "the southern fish." This name helps distinguish it from the much larger constellation Pisces, which represents two fish.

Today, it is recognized as one of the 88 modern constellations. It is generally considered a faint constellation. Most of its stars are not very bright to the naked eye. Only one star in the group is brighter than the 4th magnitude. This star is named Fomalhaut, and it is the 18th-brightest star in the night sky.

Fomalhaut is the most significant feature of this constellation. It is a white main-sequence star located 25.13 light-years away. This star is much larger and more powerful than our Sun. It is 1.92 times as massive as the Sun. It is also 16.63 times as luminous, which means it shines much more brightly. Fomalhaut is surrounded by a circumstellar disk, which is a ring of material around a star. Scientists once thought they had detected an extrasolar planet called Fomalhaut b using the Hubble Space Telescope. However, later infrared observations showed that it is actually a spherical cloud of dust.

Other stars within Piscis Austrinus show very different characteristics. Epsilon Piscis Austrini is a blue-white main-sequence star. It is located 400 light-years away and is 4.10 times as massive as the Sun. Delta Piscis Austrini is a double star. Its brighter component is a yellow giant star. This star is a red clump star that is currently burning helium in its core. Zeta Piscis Austrini is an orange giant star. Some astronomers suspect it is a variable star, meaning its brightness changes over time. Other stars, like S Piscis Austrini, are Mira-type variable red giants. These stars can change significantly in brightness over a period of 271.7 days.

This constellation has a very long history of human observation. It originated with the Babylonian constellation known as MUL.KU, or simply "the Fish." Astronomer Bradley Schaefer suggests ancient observers saw far enough south to define this fish shape. The ancient Greeks introduced the constellation around 500 BCE. They called it the Great Fish. In Greek mythology, the fish swallows water poured by Aquarius, the water-bearer. Egyptian mythology tells a different story. It says the fish saved the goddess Isis. Because of this, the fish and its descendants were placed in the heavens. In Syria, the fish was considered sacred because of stories involving the goddess Derceto.

Many different names have been used for this group of stars over the centuries. The astronomer Ptolemy listed it in the 2nd century as Ichthus Notios. German cartographers like Johann Bayer and Johann Elert Bode used the name Piscis Notius. Bayer also used the names Piscis Meridianus and Piscis Austrinus. The French astronomer Nicolas-Louis de Lacaille called it Piscis Australis. Eventually, the English astronomer John Flamsteed used Piscis Austrinus. This became the most common name. In 1922, the International Astronomical Union adopted the three-letter abbreviation "PsA." In 1930, Eugène Delporte set the official boundaries using a polygon of four segments.

There are many deep-sky objects located within these boundaries. Lacaille 9352 is a red dwarf star located only 10.74 light-years away. It is one of the brightest red dwarfs, but it is too dim to see without a telescope. Scientists have also found many exoplanets, or planets orbiting other stars, in this region. For example, the star HD 205739 has a planet 1.37 times as massive as Jupiter. The star HD 216770 has a Jupiter-like planet that orbits every 118 days. You can also find distant galaxies here, such as NGC 7172 and NGC 7314. One galaxy, NGC 7259, even hosted a supernova in 2009.

One of the most energetic objects in the constellation is PKS 2155-304. This is a BL Lacertae object, which is a type of blazar. Blazars are among the brightest objects in the sky. This object helps scientists study very high-energy processes in space. The constellation is bordered by several other groups, including Capricornus and Aquarius. It is visible to anyone observing from south of 53 degrees North latitude. By studying Piscis Austrinus, astronomers can learn about star life cycles, planet formation, and the distant reaches of our galaxy.