Ursa Minor

Look at the night sky.

You can see a little bear. It looks like a small spoon. This is why some call it the Little Dipper. It has seven bright stars.

One star is the North Star. It is the brightest star in the group. This star helps people find their way. It stays in the far northern sky. It is a very special part of the night.

Can you find it?

Look up at the far northern sky. You might see a group of stars called Ursa Minor.

This is also known as the Little Bear. In the United States, many people call it the Little Dipper. It has seven bright stars. These stars look like a small scoop or ladle.

One star is very special. It is named Polaris. This is the North Star. It is a yellow-white supergiant star. A supergiant is a very big and bright star. Polaris is the brightest star in this group.

Sailors have used Polaris to find their way for a long time. It stays near the north pole of the sky. Another star in this group is named Kochab. Kochab is an orange giant star. This means it is an older star that has grown large. Some people call Kochab and another star the "guardians of the pole star." Ursa Minor is the 56th largest constellation. It is only seen in the northern part of the world.

Ursa Minor is a constellation in the far northern sky. Many people call it the Little Bear. In the United States, it is often called the Little Dipper. This name comes from its seven bright stars. They look like a small scoop or ladle.

This group of stars is very important for finding your way. It helps people know which direction is north. The constellation is the 56th largest of the 88 modern constellations. It covers 256 square degrees of the sky.

Because it is so far north, you can only see it in the northern hemisphere.

The most famous part of this constellation is the star Polaris. Polaris is also called the North Star. It is a yellow-white supergiant star. This means it is a huge star that is very bright. It is about 432 light-years away from Earth.

Polaris is a triple star system. This means it has two other smaller stars orbiting it. The brightest star stays within 1 degree of the north celestial pole. This makes it a perfect guide for travelers. You can find it by following the two stars at the end of the Big Dipper. These are called the Pointers.

People have looked at these stars for a very long time. Long ago, the Babylonians called it the "Wagon of Heaven." They listed it in a catalogue around 1000 BC.

In the 2nd century, an astronomer named Ptolemy listed it too. The Greeks also had many names for it. One name was Cynosura, which means "dog's tail." Some stories say the stars represent a nymph named Callisto. Other myths say the stars are two bears that saved Zeus. These stories helped people remember the shapes in the sky.

There are many other interesting stars in Ursa Minor. One star is named Kochab. It is an orange giant star. This means it is an older star that has grown large.

Kochab is about 131 light-years away. It is 450 times more luminous than our Sun. Scientists found a planet orbiting Kochab as well. Another star is called Pherkad. People call Kochab and Pherkad the "guardians of the pole star." The constellation also has a very hot white dwarf star. This star is called H1504+65. It has a surface temperature of 200,000 K.

You can use Ursa Minor to learn about the night sky. The four stars in the bowl are different brightnesses. This helps you practice seeing how bright stars can be.

If you live in a city, these stars are great for testing your eyesight. In the past, sailors used these stars to sail across the sea. They knew that Polaris would always point them north. Even today, the stars of Ursa Minor remain a wonderful part of our sky. They connect us to the ancient people who first looked up in wonder.

Ursa Minor is a constellation located in the far northern sky. It is often called the Little Bear. In North America, many people call it the Little Dipper. This name comes from its seven brightest stars. These stars look like a small ladle or scoop.

This constellation is the 56th largest of the 88 modern constellations. It covers an area of 256 square degrees. Because it is in the far northern celestial hemisphere, it is only visible to observers in the northern hemisphere.

The most important star in this group is Polaris. Polaris is also known as the North Star. It is a yellow-white supergiant star. It is located about 432 light-years away from Earth. This star is a triple star system. The main supergiant star has two smaller yellow-white companions. One companion is 17 astronomical units away. The other is 2,400 astronomical units away. Polaris is also a Cepheid variable star. This means its brightness changes slightly. Its apparent magnitude ranges from 1.97 to 2.00.

Other stars in Ursa Minor have very unique properties. Beta Ursae Minoris is named Kochab. It is an orange giant star. This means it is an evolved star. It has used up the hydrogen in its core. Kochab is about 131 light-years away from us. It is 450 times more luminous than the Sun. It also has a diameter 42 times larger than the Sun. Scientists have detected a planet orbiting Kochab. This planet is about 6.1 times as massive as Jupiter.

Another star in the constellation is Gamma Ursae Minoris, or Pherkad. Kochab and Pherkad are called the "guardians of the pole star." These stars help people find the North Star. The constellation also contains very extreme objects. There is an isolated neutron star named Calvera. There is also a white dwarf named H1504+65. This is the second-hottest white dwarf ever discovered. Its surface temperature is 200,000 K. These stars show how much variety exists in space.

Humans have studied Ursa Minor for thousands of years. The Babylonians knew it as the "Wagon of Heaven." It was listed in the MUL.APIN catalogue around 1000 BC. The astronomer Ptolemy listed it in the 2nd century. The Greeks had many different names for it. One name was Cynosura, which means "dog's tail." Some myths say the stars are two bears. These bears saved Zeus from his father, Cronus.

Navigation has always relied on this constellation. In ancient times, the celestial pole was closer to Kochab. Since the medieval period, people have used Polaris to find north. Polaris stays within 1 degree of the north celestial pole. This makes it a reliable guide for mariners. In the Inuit tradition, the brightest stars are called Nuutuittut. This means "never moving." This name describes how the stars stay near the pole.

You can use Ursa Minor to practice stargazing. The four stars in the Little Dipper's bowl have different magnitudes. They range from second to fifth magnitude. This makes them great for testing your eyesight. You can find Polaris by looking at the Big Dipper. Find the two stars at the end of its bowl. These are called the Pointers. Follow a line from them for 30 degrees. This line will lead you straight to Polaris. This connection between constellations helps you map the entire sky.