Circinus is a group of stars.
It is in the night sky. It looks like a tool for drawing circles. It helps us find things in space. Do you like to look at stars?
Circinus is a group of stars.
Its name means a tool for drawing circles. A man named Lacaille found it long ago.
It is hard to see because it is faint. Some stars there have small planets. One star has two small planets. Another star has a big planet. You can also see a bright galaxy there.
Even shooting stars come from this part of the sky.
Circinus is a small group of stars in the southern sky.
Its name is Latin for a compass. This is the tool used to draw circles. A French astronomer named Nicolas-Louis de Lacaille first defined it in 1756. It is a faint part of the sky. Many of its stars are hard to see. Its brightest star is Alpha Circini. This star is special because it pulses or vibrates.
Some stars in this area have planets. One star has two small planets. Another star has a planet like Jupiter. You can also find deep objects here. There is a group of stars called an open cluster. We call this cluster NGC 5823. It looks like a reversed letter S.
There is also a spiral galaxy called the Circinus Galaxy. It is very close to our own Milky Way.
Some stars here are very powerful. One system has a neutron star. It shoots out long jets of light and matter. Even shooting stars come from this area. We call this the Alpha Circinids meteor shower.
Circinus is a small and faint constellation in the southern sky.
Its name comes from the Latin word for a drafting compass. This is a tool used to draw perfect circles. It is not a mariner's compass like the constellation Pyxis. Instead, it represents a pair of dividers used by map makers. This constellation is important because it sits near the Milky Way. The Milky Way is our own home galaxy in space. Because it is near this bright band, Circinus contains many amazing objects.
Many things happen within these star boundaries. Some stars are part of a binary system. This means two stars orbit around a common center of gravity. For example, Alpha Circini has a small orange dwarf companion. They take 2,600 years to complete one single rotation. Other stars can change in brightness over time. These are called variable stars. AX Circini is a Cepheid variable that changes every 5.3 days. Some stars even merge together to form new ones. The star BX Circini may have come from two white dwarfs joining.
A French astronomer named Nicolas-Louis de Lacaille first defined it. He did this in 1756 while studying the southern sky. He originally called the constellation le Compas in French. In 1763, he published an updated map using Latin names. He grouped it with other tools like a ruler and a level. These were part of a set of drafting instruments. Later, a Belgian astronomer named Eugène Delporte set the official borders. He did this in 1930 using a shape made of 14 segments.
There are many specific facts about the stars in Circinus. The brightest star is Alpha Circini, which is 54 light-years away. It is a special type of star that vibrates rapidly. Beta Circini is the second brightest star in the group. It is about 100 light-years away and very large. Some stars even have planets orbiting them. The star HD 134060 has two small planets. Another star, HD 129445, has a planet like Jupiter. In 185 AD, Chinese observers saw a supernova here. This was a massive explosion called SN 185.
You can connect Circinus to things you see on Earth. Just as a compass helps a builder, this constellation names a tool. You can also see meteor showers that seem to come from here. The Alpha Circinids meteor shower happens every year. It was first seen in Queensland in 1977. These meteors move at a speed of 27.1 kilometers per second. They likely come from a long-period comet in space. Looking at Circinus is like looking at a giant toolbox in the sky. It holds many different pieces of the universe's history.
Circinus is a small, faint constellation located in the southern sky. Its name is the Latin word for a drafting compass, which is a tool used to draw circles. It should not be confused with Pyxis, which represents a mariner's compass used for navigation. This constellation is significant because it intersects the plane of the Milky Way. Because it lies within our galaxy's disk, it contains many massive stars and deep-sky objects.
The constellation is visible only south of latitude 30° N. This is because its declination ranges from −50° to −70°.
Many stars in Circinus exist in complex systems. Alpha Circini is the brightest star, with an apparent magnitude of 3.19. It is a white main sequence star located 54 light-years away. It is also a rapidly oscillating Ap star, meaning it vibrates quickly. These stars have unusual spectral types that show high levels of strontium, chromium, and europium. Alpha Circini is part of a binary system. It orbits an orange dwarf companion every 2,600 years. The two stars are separated by 260 AU.
Other stars in this region show different behaviors. Beta Circini is a white main sequence star about 100 light-years away. It has a diameter roughly 1.8 times that of our Sun. Gamma Circini is a binary system located 450 light-years away. It consists of a bluish Be star and a dimmer yellow star. These two stars orbit each other every 180 years. Delta Circini is also a multiple star system. It contains two hot blue stars that orbit a common center of gravity every 3.9 days. These stars are massive, estimated at 22 and 12 times the mass of the Sun.
Variable stars are also common in this constellation. A variable star is one that changes in brightness over time. There are 493 recorded variable stars in Circinus. AX Circini is a Cepheid variable, which is a type of star that pulsates. It is a yellow-white supergiant located 1,600 light-years away. Its brightness changes over a period of 5.3 days. Another example is BX Circini. This star is thought to be the result of a merger between two white dwarfs. It is composed of over 99% helium.
Circinus contains several deep-sky objects. NGC 5823 is an open cluster that is 800 million years old. It is located 3,500 light-years away and spans 12 light-years. This cluster contains between 80 and 100 stars. Another object is the planetary nebula NGC 5315. A planetary nebula is a cloud of gas cast off by a star. This nebula is located 5.2 degrees west-southwest of Alpha Circini.
The constellation also hosts the Circinus Galaxy. Discovered in 1977, it is a spiral galaxy 26,000 light-years in diameter. It is the closest Seyfert galaxy to the Milky Way. A Seyfert galaxy is a type of galaxy with a very active nucleus.
History shows that humans have watched Circinus for a long time. In 185 AD, Chinese observers recorded a supernova in this area. A supernova is a massive stellar explosion. This event was named SN 185. The remnants of this explosion are known as RCW 86. The area of the remnant is larger than a typical full moon. The constellation itself was first defined by the French astronomer Nicolas-Louis de Lacaille in 1756. He originally named it le Compas. He later gave it the Latin name in 1763. In 1930, the Belgian astronomer Eugène Delporte set the official boundaries using 14 segments.
Extreme physics can be seen in the X-ray sources of Circinus. Circinus X-1 is an X-ray binary star system. This system includes a neutron star. In 2007, observations showed X-ray jets in this system. These jets are usually found in black hole systems.
There is also the Circinus Pulsar, known as PSR B1509-58. This pulsar is 19,000 light-years away. It has expelled a jet of material that is 20 light-years long. Finally, the Alpha Circinids meteor shower occurs annually. This shower was first observed in Queensland in 1977. The meteors travel at an average velocity of 27.1 km/s. They are likely linked to a long-period comet.
Where will your curiosity go next?
🖼️ Images & Media (4)
More to explore
✨ What else?
Related topics you might enjoy
🪜 Step back
Simpler topics to build understanding
What is Nepedia?
A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.