Explore the Closest Stars to the Sun

Artist-s_impression_of_the_planet_around_Alpha_Centauri_B_-Annotated-.jpg
Alpha Centauri B, with its possible planet (foreground) and Alpha Centauri A in the distance. ESO/L. Calçada/N. Risinger - http://www.eso.org/public/images/eso1241b/

The Sun has close stellar neighbors, although the term "close" is relative. Most of them lie at least a few light-years away, far enough that it will be a long time before anyone can visit them.

Our Sun exists in the Milky Way with hundreds of millions or perhaps trillions of other stars. It's not in the center of the galaxy, but lies out in the suburbs, well away from the core. The local neighborhood is called the Orion Arm and is about 26,000 light-years from the galaxy's center. 

Stars aren't too close together out in the suburbs of our stellar city. Compared to the core, where stars are bunched together very closely (often much less than a light-year apart), stars in the Orion arm are light-years apart. That means a trip to the closest ones would take a spaceship hundred of years to get there (unless it could travel at light-speed).

How Close is Close? 

The closest star to us is only 4.2 light-years away. That may seem close, but it's a long way for future space travelers who will eventually go there. However, in the grand scheme of the galaxy, it's right next door. 

Any future star travel is going to require long journeys or warp drive before humans can successfully explore far-off lands and stars around even our closest neighbors. What stars will they visit? Which are the closest? What are they like? We can still explore those nearby stars, however, using observatories such as the Hubble Space Telescope to get more information about them.

Proxima Centauri: 4.2 Light-years Away

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The closest star to the Sun, Proxima Centauri is marked with a red circle, close to the bright stars Alpha Centauri A and B. Courtesy Skatebiker/Wikimedia Commons.

That closest star mentioned above? It's this one: Proxima Centauri. Astronomers think it might have a planet nearby, which would be quite interesting to study. It's not clear if such a world would be habitable, due to the presence of three stars, but it's certainly worth a look.

Proxima will not always be the closest star to the Sun. That's because stars move through space. Proxima Centauri is the third star in the Alpha Centauri star system, and it's also known as Alpha Centauri C. The others are Alpha Centauri AB (a twin set). All are in a complex orbital dance that brings each member closer to the Sun at some point in their mutual orbits. 

So, in the distant future, another of its companions will be closer to Earth. It won't be a huge difference in distance, so any future star travelers won't have to worry too much about not having enough fuel to get there.

Rigil Kentaurus: 4.3 Light-years Away

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Alpha Centauri A and B. The closest star to the Sun, Proxima Centauri is marked with a red circle, close to the bright stars Alpha Centauri A and B. Courtesy Skatebiker/Wikimedia Commons.

The second-closest star is a tie between the sister stars of Proxima Centauri. These are Alpha Centauri A and B, and it looks like A will be moving closer in the distant future. And, like its sibling star, if humans can get a probe out to visit it, we could learn more about it and any planets it might be harboring.

Barnard's Star: 5.9 Light-years Away

Barnard's Star
Barnard's Star. Steve Quirk, Wikimedia Commons.

This is a faint red dwarf star, discovered in 1916 by E. E. Barnard. Recent efforts to discover planets around Barnard's Star have failed but astronomers continue to monitor it for signs of exoplanets.

So far, none have been found. If they did exist, and if they were to be habitable, they'd probably be orbiting very close to their star in order to get enough heat to support life and liquid water on the planetary surfaces.

Wolf 359: 7.7 Light-years Away

Wolfe 359
Wolf 359 is the reddish-orange star just above the center in this image. Klaus Hohmann, public domain via Wikimedia.

This star is known to many as the location of a famous battle between the Federation and the Borg on Star Trek, the Next Generation. Wolf 359 is a red dwarf. It is so small that if it were to replace our Sun, an observer on Earth would need a telescope to see it clearly.

Lalande 21185: 8.25 Light-years Away

red dwarf star
An artist's concept of a red dwarf star with a possible planet. If Lalande 21185 had a planet, it might look like this. NASA, ESA and G. Bacon (STScI)

While it is the fifth closest star to our own Sun,  dim little Lalande 21185 is about three times too faint to be seen with the naked eye. Observers need a lot of determination and a good telescope to pick out this red dwarf in the night sky.

Life forms living on a world nearby would see a faint-looking star, but it would appear fairly large in the sky. So far, no world has been found orbiting it.

Luyten 726-8 A and B: 8.73 LIght-years Away

An x-ray view of Gliese 65, also known as Luyten 726-8. Chandra X-Ray Observatory

Discovered by Willem Jacob Luyten (1899-1994), both Luyten 726-8A 726-8B are red dwarfs and too faint to be seen with the naked eye. If they have planets, they may not be life-bearing worlds.

Sirius A and B: 8.6 Light-years Away

Sirius binary star system
A Hubble Space Telescope image of Sirius A and B, a binary system 8.6 light-years away from Earth. NASA/ESA/STScI

Sirius, also known as the Dog Star, is the brightest star in the night sky and a relatively close neighbor to the Sun. It has a companion called Sirius B, which is a white dwarf. The heliacal rising of this star (that is, it's rise just before sunset) was used by the ancient Egyptians as a way to know when the Nile would start flooding each year.

Observers can spot Sirius in the sky starting in late November. It's very bright and lies not far from the constellation outline of Orion, the Hunter. It's not known if Sirius has any planets.

Ross 154: 9.7 Light-years Away

Ross 154
Could Ross 154 look like this up close?. NASA

Ross 154 appears to be a flare star, which means that it can increase its brightness by a factor of 10 or more before reverting to its normal state, a process which takes only a few minutes. No good images of it exist. As far as having habitable planets, if it does, those flares would pose a huge risk to life on their surfaces (if any exists).

Ross 248: 10.32 Light-years Away

ross 248
An artist's conception of a planet circling around a red dwarf star (in the distance) similar to Ross 248. STScI

Right now, this one is the ninth-closest star to our solar system. However, around the year 38,000 AD, this red dwarf will get so close to the Sun that it will take the place of Proxima Centauri as the closest star to us. Red dwarf stars can harbor planets, although for life to exist on them, they'd need to be fairly close by.

Epsilon Eridani: 10.5 Light-years Away

epsilon eridani
Epsilon Eridan (in yellow) has at least one exoplanet. This nearby star is under intense scrutiny by astronomers. NASA

Epsilon Eridani is among the closest stars known to have a planet, Epsilon Eridani b. The structure of this star and its system is somewhat similar to the Sun and solar system.

This is the third-closest star that is viewable without a telescope, in the constellation Eridanus. The discovery of an exoplanet here piqued the curiosity of astronomers, who are working to understand what kind of world it is. The star it orbits is a young, highly magnetic one, making this system doubly fascinating to astronomers.

Sources

  • “Ask an Astronomer.” Cool Cosmos, coolcosmos.ipac.caltech.edu/ask/208-Which-star-is-closest-to-us-.
  • NASA, NASA, imagine.gsfc.nasa.gov/features/cosmic/nearest_star_info.html.
  • “The Closest Star to the Earth.” Scorpius, www.astro.wisc.edu/~dolan/constellations/extra/nearest.html.