Orion’s Belt Stars

by Tega Jessa on April 17, 2011

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Orion's Belt Stars

The Orion's Belt stars (including Mintaka). Credit: http://www.freewebs.com

Orion’s belt stars are some of the most famous stars in the night sky. They also make up one of the most well-known and easy to find constellations, Orion’s belt. Every major civilization from the Babylonians and Egyptians to the Greeks had different stories for the constellation. In Greece the constellation is known as that of the Greek hero and hunter Orion who was killed by a Scorpion. In ancient Egypt, Orion’s belt was known as the symbol of the God-pharaoh, Osiris Orion’s belt consists of three stars. The names of the stars are Mintaka, Alnilam, and Alnitak. Each of the stars’ names come from Arabic. Mintaka means belt, Alnilam means “a belt of pearls”, and Alnitak means the girdle. Scientists believe the three stars formed around the same time from one of the nebulas found in the Orion constellation. So let’s find out more about these stars.

Mintaka is a super-giant star and is white blue. It is 800 light years from Earth and is the westernmost star in the Orion belt from our perspective on Earth. The star is 10,000 times brighter than our sun and has a searing hot surface temperature of 60,000 degrees Celsius. Its mass is 20 times that of the Sun.

Alnilam is the center star of Orion’s belt. The star is also a white blue super giant. It is 1,000 light years from Earth. Alnilam is the brightest of Orion’s belt stars at 18,000 times brighter than our Sun. the Star’s is about the same mass as its fellow stars at 20 solar masses. The surface temperature is actually the coolest of the three starts at 50,000 degrees Celsius.

The third star, Alnitak is the dimmest of the stars. Even though it has the same mass and surface temperature as Mintaka it is only 7,000 times brighter than the Sun. Alnitak is 900 light years away so it falls in the middle when it comes to distance from the Earth.

An interesting fact about the Orion’s belt stars is that they are not single stars but systems of stars. Supergiant stars like the Orion’s belt stars tend to have sibling stars that orbit. This is the case for Mintaka and Alnilam. This shows how perception from Earth is not entirely accurate. Another important fact is that the Orion constellation has a very famous system of nebulas. One of the most famous is the Horsehead Nebula.

We have written many articles about Orion’s Belt for Universe Today. Here’s an article about Orion’s Belt, and here’s an article about the Orion nebula.

If you’d like more information on stars, check out Hubblesite’s News Releases about Stars, and here’s the stars and galaxies homepage.

We’ve done many episodes of Astronomy Cast about stars. Listen here, Episode 12: Where Do Baby Stars Come From?


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