Determined by Apparent Magnitude, these are the 20 brightest stars in the sky from brightest to ... less bright. Magnitude measures brightness as seen from inside Earth's atmosphere... not necessarily size or importance. Which stars are the brightest?Planets may be the brightest *things* in the sky, but they don't count as stars. The white and blue stars tend to be the hottest and shiniest... but some red stars are closer to earth, so they will appear brighter, even when they aren't in actuality. If you've ever looked up and wondered what that big mess was all about, here are some names to give to those bright dots... and a few directions for how to find them.
In the constellation of Canus Major, Sirius is the brightest star in the night sky, outdistancing #2 on the list by twice as much. The star we see as Sirius was actually a binary star consisting of a white main sequence star (Sirius A) and a faint white dwarf companion (Sirius B). However, Sirius B went supernova, and while its remains help Sirius remain king of Bright, it's no longer two stars. It's bright because of both its luminosity and its proximity to Earth. Two times as massive as our sun and 25 times more luminous, the "Dog Star" is in a system that is between 200 and 300 million years old.If you can't immediately find it by its brightness, just find Orion's belt and follow its line to the left to Sirius. You can't miss it. It also forms one point of the "Winter Triangle" with fellow mates, Procyon and Betelguese.
Found in the constellation Bootes, Arcturus looks a little orangey-yellow. It would actually be behind Alpha Centauri in brightness except for the fact that Alpha Centauri is actually two stars, and that wouldn't be fair. It's an orange giant, 110 times more luminous than our sun. Its mass is unknown, but thought to be only slightly larger than our sun.An easy way to find it is to follow the arc of the Big Dipper's handle to Arcturus.
Magnitude: -0.72This sparkler is in Carina. It is the brightest star in the Southern Hemisphere. Canopus is a "supergiant" spectral type F star that is 15,000 times more luminous than our sun and 65 times bigger. If you put it in the center of our solar system, it would extend three quarters of the way to Mercury.
In the constellation Lyra, Vega is the fifth brightest star in the sky and the second brightest in the Northern Hemisphere. It's also pretty close to earth at just 25 light years away. Scientists say it's the most important star in the sky, after our sun, precisely because of its proximity to earth and also because it is thought to have a planet, based on irregularities in its disk. Its only one tenth the age of our sun but it's 2.1 times as massive. You can see it in the Northern Hemisphere in the summer and, in fact, it is one of three stars (including Altair and Deneb) that make up the bright "Summer Triangle."Follow the two stars of the Big Dipper that make up the back of the "cup." Go up, up, up in a straight line past Cassiopeia... and you can't miss it.
Magnitude: 1.33You see Alpha Centauri as one star, but it's actually a binary system comprised of A and B. There's even a third star associated with the system called Proxima which is the closest star to our sun. If you have a telescope, you can actually see both stars, and they say that ancient Greek and Arab armies used to use its duality as an eye test for their men. This group of three stars is in the constellation Centaurus, and can only really be seen by folks in the Southern Hemisphere.
Magnitude: 0.34Procyon is another point in the Winter Triangle (along with Betelguese and Sirius). It's in the constellation Canus Minor. You can see it just above Sirius, next to Orion. It's a white star, bright for its class, which suggests its going to start expanding "soon." Procyon is about 1.4 times the mass of our sun and 7.5 times more luminous.