Piscis Austrinus facts for kids
| Constellation | |
List of stars in Piscis Austrinus
|
|
| Abbreviation | PsA |
|---|---|
| Genitive | Piscis Austrini |
| Pronunciation | or genitive |
| Symbolism | the Southern Fish |
| Right ascension | 21h 27m 13.8661s–23h 06m 54.6033s |
| Declination | -24.8250446°–-36.4592972° |
| Quadrant | SQ4 |
| Area | 245 sq. deg. (60th) |
| Main stars | 7 |
| Bayer/Flamsteed stars |
21 |
| Stars brighter than 3.00m | 1 |
| Stars within 10.00 pc (32.62 ly) | 3 |
| Brightest star | Fomalhaut (α PsA) (1.16m) |
| Messier objects | 0 |
| Meteor showers | ? |
| Bordering constellations |
Capricornus Microscopium Grus Sculptor Aquarius |
| Visible at latitudes between +55° and −90°. Best visible at 21:00 (9 p.m.) during the month of October. |
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Piscis Austrinus is a cool constellation you can find in the southern part of the night sky. Its name means "the Southern Fish" in Latin, which helps you remember it's different from the bigger constellation Pisces (the two fish). Before the 1900s, people sometimes called it Piscis Notius.
A long time ago, around 150 AD, a famous astronomer named Ptolemy listed Piscis Austrinus. It's still one of the 88 constellations we recognize today! Some stars that are now part of the Grus constellation (the Crane) were once considered the "tail" of Piscis Austrinus. But in the late 1500s, a mapmaker named Petrus Plancius made Grus its own constellation.
This constellation isn't super bright, but it has one very special star: Fomalhaut. It's the 18th brightest star you can see in the whole night sky! Fomalhaut has a ring of dust around it, and scientists think it might even have a planet orbiting it. Other cool things in Piscis Austrinus include Lacaille 9352, a bright red dwarf star (too dim to see without a telescope), and PKS 2155-304, which is a very bright blazar – a type of galaxy with a super active center!
Contents
Discovering the Southern Fish Constellation
The idea of Piscis Austrinus started with the ancient Babylonians, who simply called it "the Fish." Around 500 BCE, the Ancient Greeks learned about this constellation. They also knew about other constellations like Aquila (the Eagle) and Hydra (the Water Snake). These constellations helped them mark the summer solstice and winter solstice.
In Greek mythology, Piscis Austrinus is known as the Great Fish. It's often shown drinking the water poured by Aquarius, the water-bearer. Some stories say the two fish of the Pisces constellation are the children of this Great Fish.
Ancient Egyptians also had a story about this fish. They believed it saved the life of their goddess Isis. Because of this brave act, Isis placed the fish and its family among the stars.
A Greek historian named Ctesias wrote another tale in the 5th century BC. He said a fish in a lake near Syria saved Derceto, who was the daughter of Aphrodite. To honor this deed, the fish was put into the sky. Because of this story, many people in Syria considered fish sacred and did not eat them.
What Makes Piscis Austrinus Special?
Piscis Austrinus is surrounded by other constellations. To its northwest is Capricornus (the Sea-Goat). To the southwest, you'll find Microscopium (the Microscope). Grus (the Crane) is to the south, Sculptor (the Sculptor) to the east, and Aquarius (the Water-Bearer) to the north.
The International Astronomical Union (IAU) gave Piscis Austrinus the short abbreviation "PsA" in 1922. This makes it easier for astronomers to talk about it.
Many astronomers throughout history have given this constellation different names. Ptolemy called it "Ichthus Notios," meaning "Southern Fish." Later, others like Johann Bayer and Johann Elert Bode used names like Piscis Notius or Piscis Meridianus. Eventually, most astronomers, including John Flamsteed, settled on Piscis Austrinus.
In 1930, a Belgian astronomer named Eugène Delporte officially set the exact borders for all constellations. Piscis Austrinus has a specific shape defined by these borders. If you live south of about 53°N latitude, you can see the entire constellation in the sky.
Stars and Deep-Sky Wonders
Bright Stars and Distant Worlds
Long ago, astronomers counted about twelve stars in Piscis Austrinus. However, some of these stars later became part of other constellations like Grus or Microscopium. Astronomers like Bayer and Ptolemy used Greek letters to name the brightest stars. Today, we recognize 47 stars in Piscis Austrinus that are bright enough to see with a small telescope.
The brightest star in Piscis Austrinus is Fomalhaut. It's often thought of as the fish's mouth. Fomalhaut is the 18th brightest star in our entire night sky! It's a white main-sequence star located about 25 light-years away. This star is almost twice as massive and much brighter than our Sun. Scientists once thought they saw a planet, Fomalhaut b, orbiting it with the Hubble Space Telescope. However, later studies showed it was likely a large cloud of dust instead of a planet.
The second brightest star here is Epsilon Piscis Austrini. It's a blue-white star, much farther away at about 400 light-years. It's also much bigger and brighter than our Sun.
In China, three stars – Beta, Delta, and Zeta – were known as the "heavenly rope." Beta is a white star similar to Fomalhaut but five times farther away. Delta Piscis Austrinis is actually two stars orbiting each other! The brighter one is a yellow giant star. Zeta Piscis Austrini is an orange giant star and might change its brightness over time.
Some stars in Piscis Austrinus are called "variable stars" because their brightness changes. For example, S Piscis Austrini is a red giant that gets brighter and dimmer over about 271 days. V Piscis Austrinus also changes brightness over 148 days.
One interesting star is Lacaille 9352. It's a faint red dwarf star, less than half the size of our Sun. Even though it's only about 10.74 light-years away, it's too dim to see without a telescope. In June 2020, scientists discovered two super-Earth planets orbiting Lacaille 9352!
Scientists have also found planets around five other stars in this constellation:
- HD 205739 is a yellow-white star with a planet bigger than Jupiter.
- HD 216770 is an orange dwarf star with a planet similar to Jupiter.
- HD 207832 has two giant planets, both smaller than Jupiter, orbiting it.
- WASP-112 and WASP-124 are two Sun-like stars that also have planets.
Galaxies and Cosmic Blazars
Beyond the stars, Piscis Austrinus also holds some amazing deep-sky objects.
- NGC 7172, NGC 7174, and NGC 7314 are three different galaxies you can observe.
- NGC 7259 is a spiral galaxy where a supernova (a huge star explosion) called SN 2009ip was seen in 2009.
- PKS 2155-304 is a very special and bright object called a blazar. Blazars are galaxies with super-active centers that shoot out powerful jets of energy.
See also
In Spanish: Piscis Austrinus para niños
- Piscis Austrinus in Chinese astronomy
