What is the Closest Star to Earth?
Written by Fraser Cain
Question: What is the closest star?
Answer: The Sun.
That was an easy one… next question?
Okay, fine, it was a trick question, I know. Let's see if we can come up with the actual answer to the question, "except for the Sun, what is the closest star?"
The closest star system that we know of is Alpha Centauri, located about 4.37 light years away (41.5 trillion km). The system easy to see with the unaided eye – if you live in the Southern hemisphere. In fact, Alpha Centauri is the 4th brightest star in the star in the sky.
But there's a catch. Alpha Centauri is actually made up of three stars orbiting one another. They're too bright to be seen as separate stars without a telescope. But with a telescope, it's possible to split the star into two. These are Alpha Centuari A and B.
So which one's closer? Neither.
The Alpha Centauri system has a third, much dimmer star called Proxima Centauri. While Alpha Centauri A and B are 4.37 light-years away, The red dwarf Proxima Centauri is located a mere 4.22 light-years away. If humans ever reach out to launch spacecraft to another world, Proxima Centauri would be their likely destination.
Alpha Centauri orbit one another, getting as close as 11.2 astronomical units (the distance from the Sun to Saturn), while Proxima Centauri is about 13,000 astronomical units away. Most astronomers think that Proxima Centauri orbits the binary pair, but there are some who think it's just passing by, and not actually part of the system.
Here's a list of the 10 closest stars, with their distance in light-years:
Proxima Centauri – 4.22
Alpha Centauri A – 4.37
Alpha Centauri B – 4.37
Barnard's Star – 5.96
Wolf 359 – 7.78
Sirius A – 8.58
Sirius B- 8.58
Luyten-8 A – 8.73
Luyten-8 B – 8.73
Ross 154 – 9.68
Filed under: Astronomy
