The brightest stars in our night sky are an object of constant interest to stargazers. Some appear very bright to us because they're relatively nearby, while others look bright because they're massive and very hot, pumping out lots of radiation. Some look dim because of their age, or because they're far away. There's no way to tell just by looking at a star what its age is, but we can tell brightness and use that to learn more.
Stars are massive shining spheres of hot gas that exist in all galaxies across the universe. They were among the first objects to form in the infant universe, and they continue to be born in many galaxies, including our Milky Way. The star closest to us is the Sun.
All stars are made primarily of hydrogen, smaller amounts of helium, and traces of other elements. The stars we can see with the naked eye in the night sky all belong to the Milky Way Galaxy, the huge system of stars that contains our solar system. It contains hundreds of billions of stars, star clusters, and clouds of gas and dust (called nebulae) where stars are born.
Here are the ten brightest stars in Earth's night sky. These make excellent stargazing targets from all but the most light-polluted cities.
Sirius, also known as the Dog Star, is the brightest star in the night sky. Its name comes from the Greek word for "scorching." Many early cultures had names for it, and it had special meanings in terms of rituals and the deities they saw in the sky.
It's actually a double star system, with a very bright primary and a dimmer secondary star. Sirius is visible from late August (in the early mornings) until mid-to-late March) and lies 8.6 light-years away from us. Astronomers classify it as a type A1Vm star, based on their method of classifying stars by their temperatures and other characteristics.
Canopus was well known to the ancients and is named either for an ancient city in northern Egypt or the helmsman for Menelaus, a mythological king of Sparta. It's the second brightest star in the night sky, and mainly visible from the Southern Hemisphere. Observers who live in the southern regions of the Northern Hemisphere can also see it low in their skies during certain parts of the year.
Canopus lies 74 light-years away from us and forms part of the constellation Carina. Astronomers classify it as a type F star, which means it's slightly hotter and more massive than the Sun. It's also a more aged star than our Sun.
Rigel Kentaurus, also known as Alpha Centauri, is the third brightest star in the night sky. Its name literally means "foot of the centaur" and comes from the term "Rijl al-Qanṭūris" in Arabic. It's one of the most famous stars in the sky, and first-time travelers to the Southern Hemisphere are often eager to view it.
Rigel Kentaurus is not just one star. It's actually part of a three-star system, with each star looping around with the others in an intricate dance. It lies 4.3 light-years away from us and is part of the constellation Centaurus. Astronomers classify Rigel Kentaurus as a type G2V star, similar to the Sun's classification.It may be about the same age as our Sun and is in roughly the same evolutionary period in its life.
Arcturus is the brightest star in the northern-hemisphere constellation Boötes. The name means "Guardian of the Bear" and comes from ancient Greek legends.Stargazers often learn it as they star-hop from the stars of the Big Dipper to find other stars in the sky. There's an easy way to remember it: simply use the curve of the Big Dipper's handle to "arc to Arcturus."
This is the 4th-brightest star in our sky and lies just around 34 light-years away from the Sun. Astronomers classify it as a type K5 star which, among other things, means it is slightly cooler and a bit older than the Sun.
Vega is the fifth-brightest star in the night sky. Its name means "the swooping eagle" in Arabic. Vega is about 25 light-years from Earth and is a Type A star, meaning it is hotter and somewhat younger than the Sun.
Astronomers have found a disk of material around it, which could possibly hold planets. Stargazers know Vega as part of the constellation Lyra, the Harp. It's also a point in an asterism (star pattern) called the Summer Triangle, which rides through the Northern Hemisphere skies from early summer to late autumn.
The sixth brightest star in the sky is Capella. Its name means "little she-goat" in Latin, and it was charted by many ancient cultures, including the Greeks, Egyptians, and others.
Capella is a yellow giant star, like our own Sun, but much larger. Astronomers classify it as a type G5 and know that it lies some 41 light-years away from the Sun. Capella is the brightest star in the constellation Auriga, and is one of the five bright stars in an asterism called the "Winter Hexagon".
Rigel is an interesting star that has a slightly dimmer companion star that can be easily seen through telescopes. It lies about860 light-years away but is so luminous that it's the seventh-brightest star in our sky.
Rigel's name comes from the Arabic word for "foot" and it is indeed one of the feet of the constellation Orion, the Hunter. Astronomers classify Rigel as a Type B8 and have discovered it is part of a four-star system. It, too, is part of the Winter Hexagon and is visible from October through March each year.
Procyon is the eighth brightest star night sky and, at 11.4 light-years, is one of the closer stars to the Sun. It's classified as a Type F5 star, which means it's slightly cooler than the Sun. The name "Procyon" is based on the Greek word "prokyon" for "before the Dog" and indicates that Procyon rises before Sirius (the dog star). Procyon is a yellow-white star in the constellation Canis Minor and is also part of the Winter Hexagon. It's visible from most parts of both the northern and hemispheres and many cultures included it in their legends about the sky.
The ninth-brightest star night sky is Achernar. This bluish-white supergiant star lies about 139 light-years from Earth and is classified a Type B star. Its name comes from the Arabic term "ākhir an-nahr" which means "End of the River." This is very appropriate since Achernar is part of the constellation Eridanus, the river.It's part of the Southern Hemisphere skies, but can be seen from some parts of the Northern Hemisphere such as the southern United States and southern Europe and Asia.
Betelgeuse is the tenth-brightest star in the sky and makes the upper left shoulder of Orion, the Hunter. It's a red supergiant classified as a type M1, is about 13,000 times brighter than our Sun. Betelgeuse lies some 1,500 light-years away. The name comes from the Arabic term "Yad al-Jauza," which means "arm of the mighty one". It was translated as "Betelgeuse" by later astronomers.
To get an idea of how large this star is, if Betelgeuse were put at the center of our Sun, its outer atmosphere would extend past the orbit of Jupiter. It's so large because it has expanded as it ages. Eventually, it will explode as a supernova sometime in the next few thousand years.
No one is quite sure exactly when that explosion will occur. Astronomers have a good idea of what will happen, however. When that star death occurs, Betelgeuse will temporarily become the brightest object in the night sky. Then, it will slowly fade out as the explosion expands. There may also be a pulsar left behind, consisting of a rapidly spinning neutron star.
Edited and updated byCarolyn Collins Petersen.