This is a group of stars.
It looks like a small horse. It is very hard to see. It is small in the sky. We can look for it at night. Do you like horses?
This group of stars is called Equuleus.
Its name means a little horse. It is a very small part of the sky. It is also hard to see.
Some people say it is a horse's head. It sits near a bigger horse in the sky. This little horse is the second smallest group of stars. It has a bright star called Kitalpha. This star is very far away. It is fun to look for it at night.
Equuleus is a small group of stars in the sky.
Its name means "little horse" in Latin. It is the second smallest constellation.
It is very faint and hard to see. No stars in it are very bright.
The brightest star is called Kitalpha. This star is 186 light-years away. It is a yellow star. Some stars in Equuleus change in brightness. We call these variable stars. One star, R Equulei, changes over 261 days. There are also double stars. These are two stars that look close together. One system, epsilon Equulei, is a triple star. This means it has three stars.
Equuleus does not have many star clusters. It does have some faint galaxies. A galaxy is a huge group of stars. Some are very hard to see.
Old stories tell us about this horse. One myth says it is a foal. A foal is a young horse. This foal was a brother to Pegasus. Pegasus was a famous winged horse. Because it rises early, some call it the First Horse.
Equuleus is a tiny group of stars in the night sky.
Its name is Latin for a "little horse" or a foal. It is the second smallest constellation we know today. Only the constellation Crux is smaller than it. It covers just 72 square degrees of the sky. This constellation is very faint to look at. No star in it is brighter than a fourth magnitude. This means you need dark skies to see it well.
Many stars in this area have special ways of working. Some are variable stars, which means their brightness changes. For example, the star R Equulei changes over about 261 days. Another star, gamma Equulei, changes every 12.5 minutes. There are also many double stars in this group. A double star is actually two stars close together. The star epsilon Equulei is even more complex. It is a triple star system with three stars.
People have studied these stars for a very long time. An astronomer named Ptolemy listed it in the 2nd century. He was one of the first to name it. Later, a man named Bayer gave names to four stars. These names were Alpha through Delta. In 1801, another astronomer named Bode added more names. He used names like Lambda, but we do not use them much now. Most people still use the name Epsilon for one of the stars.
There are many specific facts about the stars here. The brightest star is Alpha Equulei, also called Kitalpha. It is a yellow star 186 light-years away. Kitalpha means "the section of the horse." Another star, delta Equulei, is a binary star system. This means two stars orbit each other every 5.7 years. This was once the shortest known orbit for such stars. Equuleus also has very faint galaxies. These include NGC 7015 and NGC 7046.
Old stories help us understand why this shape exists. In Greek myths, it might be a foal named Celeris. Celeris was the brother of the winged horse Pegasus. Some stories say the horse came from Poseidon's trident. Because it rises before Pegasus, people call it the First Horse. In Chinese astronomy, these stars are part of a different group. They are located within the Black Tortoise of the North.
Equuleus is a faint constellation located just north of the celestial equator. Its name is Latin for "little horse," which refers to a foal. This grouping is one of the 88 modern constellations used by astronomers today. It is quite small in the vast sky. In fact, it is the second smallest constellation known. Only Crux is smaller, covering a tiny area of 72 square degrees.
Because it is so small and distant from the plane of the Milky Way, it lacks many large objects. It is somewhat devoid of deep-sky objects like bright star clusters or large nebulae. However, it does contain several very faint galaxies. These are found in the New General Catalogue, such as NGC 7015, NGC 7040, and NGC 7046. Another interesting object is NGC 7045. This is a triple star system that the discoverer John Herschel once mistook for a nebula.
Many stars within Equuleus exhibit interesting behaviors, such as being variable stars. A variable star is one that changes in brightness over time. There are about 25 known variable stars in this constellation, though most are very faint. For example, gamma Equulei is an alpha2 CVn type variable star. It is a white star located 115 light-years from Earth. Its brightness changes between magnitudes 4.58 and 4.77 every 12.5 minutes. Another example is R Equulei, which is a Mira variable star. Its brightness ranges from magnitude 8.0 to 15.7 over a period of nearly 261 days.
Astronomers also study the complex star systems in this region. The brightest star is alpha Equulei, also known as Kitalpha. This yellow star is 186 light-years away and has a magnitude of 3.9. Its name means "the section of the horse." Another system, epsilon Equulei, is a triple star system also called 1 Equulei. It is located 197 light-years away. It consists of a primary binary star and a secondary star. The primary components have a period of 101 years. These two stars are moving closer together. Because of this, they will not be divisible in amateur telescopes starting in 2015.
Binary stars are another major feature of Equuleus. A binary star system consists of two stars that orbit one another. The star delta Equulei is a binary system with an orbital period of 5.7 years. At one time, this was the shortest known orbital period for an optical binary. The two components of this system stay very close, never more than 0.35 arcseconds apart. Additionally, gamma Equulei has an optical companion called 6 Equulei. This companion has a magnitude of 6.1. The system 6 Equulei is itself an astrometric binary with a magnitude of 6.07.
Humans have been mapping these stars for many centuries. The astronomer Ptolemy included Equuleus in his list of 48 constellations during the 2nd century. The constellation was originally created by Hipparchus. Later, the astronomer Bayer assigned designations to four stars, from Alpha through Delta. In 1801, the astronomer Bode added more designations up to Lambda. Today, most people only use the designation Epsilon from that list.
Mythology provides different ways to view this constellation. In Greek myths, Equuleus may represent the foal Celeris. Celeris was the offspring or brother of the winged horse Pegasus. Some stories say the horse was struck by Poseidon's trident during a contest with Athena. Because this constellation rises before Pegasus, it is sometimes called Equus Primus, or the First Horse. Other myths link the stars to Philyra and Saturn. In Chinese astronomy, these stars belong to a different system. They are located within the Black Tortoise of the North.
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