Sagitta

Look up at the night sky. You can see a shape. It looks like an arrow. This arrow is called Sagitta.

It is a small group of stars. It is the third smallest group in the sky. Some stars look like the tip of the arrow. Other stars look like the long shaft.

Some stars in this group are very big. One star is much larger than our Sun. It has also grown very bright.

Some stars have planets near them. These planets are like Jupiter. They spin around their stars.

There are also clouds of gas in the sky.

These clouds look like soft shapes. The arrow is a wonderful thing to find.

Look up at the northern sky to find Sagitta. Its name is Latin for "arrow." It is a small group of stars. In fact, it is the third smallest group in the sky.

Some stars make the shape of an arrow. The brightest star is Gamma Sagittae. It is a red giant star. This means it is old and large. It is 54 times wider than our Sun. Other stars in the group are also very big. Some stars are actually groups of stars that orbit each other.

We can also find planets in this area. Two star systems have planets like Jupiter. One star has a brown dwarf near it. A brown dwarf is a very small, cool object. It is much bigger than a planet but smaller than a star.

You can also see Messier 71. This is a loose globular cluster. It is a big group of stars held together by gravity. The Milky Way also passes through this part of the sky.

This image shows a star surrounded by gas.

Sagitta is a small but distinct constellation in the northern sky. Its name is Latin for "arrow." It is not to be confused with the much larger constellation Sagittarius, which is "the archer." Sagitta is one of the 88 modern constellations defined by the International Astronomical Union. It covers 79.9 square degrees of the sky. This means it makes up only 0.194% of the total sky area. In fact, it is the third-smallest constellation. Only Equuleus and Crux are smaller than Sagitta.

Many stars in Sagitta work in interesting ways. The brightest star is Gamma Sagittae. It is an aging red giant star. It has 90% of the mass of our Sun. However, it has expanded to a radius 54 times greater than the Sun. Other stars in the group are also complex. Delta Sagittae is a binary system. This means two stars orbit each other every ten years. One is a red supergiant, and the other is a blue-white star. Some stars, like V Sagittae, are cataclysmic variables. This is a system where a white dwarf pulls mass from a companion star. This process might make V Sagittae one of the brightest stars in our sky around the year 2083.

People have known about this constellation for a very long time. The astronomer Ptolemy listed it in the 2nd century. The ancient Greeks also called it "the arrow." Some stories say it was the weapon Hercules used. Other scholars said it was the arrow used by Apollo. In Arabic, the name became al-sahm, which also means "arrow." Later, the name changed to Sham for the star Alpha Sagittae. In 1922, the International Astronomical Union gave it the three-letter code "Sge." An American astronomer named Henry Norris Russell created this code. He used the letter "e" to make sure it was different from Sagittarius.

There are many specific details about the stars and objects in Sagitta. The star Alpha Sagittae is a yellow bright giant. It is four times as massive as our Sun. The star Beta Sagittae is about 129 million years old. It is 4.33 times as massive as the Sun. We can also find planets in this constellation. The star HD 231701 has a Jupiter-like planet. Another star called HAT-P-34 has a planet that is one time the mass of Jupiter. There is also a star named 15 Sagittae. It has a brown dwarf companion that is 69 times as massive as Jupiter.

Sagitta connects to many famous parts of our universe. The band of the Milky Way passes right through it. This includes the Great Rift, which is a dark area in our galaxy. Between the stars Beta and Gamma, you can find Messier 71. This is a loose globular cluster of stars. It was first discovered by Philippe Loys de Chéseaux in 1745 or 1746. It is located about 7,000 light-years away from Earth. Looking at Sagitta helps us see how stars live and change. It shows us how stars can expand, shrink, or even merge together.

Sagitta is a small but distinct constellation located in the northern sky. Its name is Latin for "arrow," which distinguishes it from the much larger constellation Sagittarius, known as "the archer." Sagitta is one of the 88 modern constellations officially recognized by the International Astronomical Union. It covers an area of 79.9 square degrees. This represents only 0.194% of the total sky. Because of its small size, Sagitta is the third-smallest constellation. Only Equuleus and Crux occupy a smaller area of the celestial sphere.

The constellation is defined by a specific set of stars that form an arrow-shaped asterism. This shape is located due north of the bright star Altair. The brightest star in the group is Gamma Sagittae, which has an apparent magnitude of 3.47. This star is an aging red giant. It possesses about 90% of the mass of our Sun. However, it has expanded to a radius 54 times larger than the Sun. It is also 575 times as bright. Gamma Sagittae is likely on the red-giant branch of its life. This means it has exhausted its core hydrogen and now burns it in a surrounding shell.

Many stars within Sagitta are complex systems involving multiple bodies. Delta Sagittae is a binary star system, meaning two stars orbit one another. These two stars complete an orbit every ten years. One component is a red supergiant with 3.9 times the mass of the Sun. The other is a blue-white main sequence star with 2.9 times the mass of the Sun. Zeta Sagittae is a triple star system located approximately 140 light-years from Earth. Other stars, such as Epsilon Sagittae, are also double stars. In these systems, the components can often be seen using small telescopes.

History shows that humans have observed Sagitta for many centuries. The 2nd-century astronomer Ptolemy included it in his list of 48 constellations. The ancient Greeks also recognized it as an arrow. Some myths suggested it was the weapon Hercules used to kill the eagle of Jove. Other scholars, like Eratosthenes, linked it to the god Apollo. In Arabic, the name was al-sahm, meaning "arrow." In 1922, the International Astronomical Union adopted the three-letter abbreviation "Sge." This code was created by American astronomer Henry Norris Russell. He chose the letter "e" to ensure the code was not confused with Sagittarius.

Some stars in Sagitta are known for their dramatic changes in brightness. These are called variable stars. V Sagittae is a cataclysmic variable. This is a binary system where a white dwarf pulls mass from a donor star. This process is expected to cause a luminous red nova around the year 2083. At that time, it may briefly become the most luminous star in the Milky Way. Another example is FG Sagittae, a "born again" star. This star reignited its helium shell fusion recently. It expanded from a blue supergiant to a K-class supergiant in less than 100 years.

Astronomers have also discovered planets orbiting stars within this constellation. The star HD 231701 hosts a Jupiter-like planet. Another star, HAT-P-34, has a planet with one times the mass of Jupiter. The system 15 Sagittae is particularly interesting. It is a solar analog, meaning it is very similar to our Sun. However, it has a brown dwarf companion. A brown dwarf is a substellar object that is much larger than a planet but smaller than a star. This companion is about 69 times as massive as Jupiter and takes 73.3 years to orbit the star.

Sagitta also contains fascinating deep-sky objects. The band of the Milky Way and the Great Rift pass through the constellation. The stars Alpha, Beta, and Epsilon Sagittae mark the border of the Rift. Located between Beta and Gamma Sagittae is Messier 71. This is a loose globular cluster of stars. It was discovered by Philippe Loys de Chéseaux around 1745 or 1746. It sits about 7,000 light-years away from Earth. It has a mass of about 10,000 solar masses and a luminosity of 19,000 solar luminosities.

Finally, the constellation features high-energy objects like the black widow pulsar. This is a massive neutron star. It is the second millisecond pulsar ever discovered. The pulsar is currently ablating its companion, which is a brown dwarf. This process causes the pulsar's radio signals to weaken as they pass through ejected material.

Studying Sagitta allows astronomers to observe many different stages of stellar evolution. It provides a window into how stars live, die, and interact with their neighbors.