Alpha Centauri (Rigil Kentaurus): Our Sun’s Closest Neighbor
Alpha Centauri (Rigil Kentaurus) is the closest star system away from our sun. It’s about 4.3 light years away from Earth.
Or another way to measure it – Alpha Centauri distance is about 25 trillion miles away! Overall, it’s about 3 times closer to the next sun-like star.
Recently, International Astronomical Union (IAU) recently made the name change from Alpha Centauri to Rigil Kentaurus official.
It took back its ancient moniker “Rigil Kentaurus” which means “foot of the centaur” in Arabic.
How many stars are in Alpha Centauri? Are there any Earth-like planets in its system? And is Alpha Centauri getting closer or farther away from Earth?
Alpha Centauri is a triple star system
The Alpha Centauri system contains the following 3 stars which are all bound by gravity:
- First, Alpha Centauri A is close to our sun in age and luminosity. Alpha Centauri A and B orbit closely to each other.
- Second, Alpha Centauri B is smaller and dimmer than our sun. But it’s still not too different from our sun.
- Lastly, Alpha Centauri C (Proxima Centauri) is a smaller red dwarf star with a much larger orbit. Because of its orbit, Proxima Centauri is the closest star to Earth.
The diagram above illustrates the locations of the star systems closest to the sun. The year when the distance to each system was determined is listed after the system name. Close neighborhood is mostly red and brown dwarfs, probably without any planets.
Alpha Centauri is one of the most exciting star systems in the universe. Not only because it’s the closest star system to our own, but it has potential of life.
In fact, astronomers have already found a rocky planet approximately the size of Earth in the habitable zone of Proxima Centauri. Not only can liquid water persist due to its proximity to Proxima Centauri, but it’s also the closest exoplanet to Earth.
This is why NASA plans to launch a probe towards Alpha Centauri in 2069. The intent of this interstellar space mission is to search for biosignatures on planets around the stars in the Alpha Centauri system.
Even here in our Milky Way galaxy, there at least 10 possible habitable planets. This includes the exoplanet within Proxima Centauri.
A collision course with Earth
Alpha Centauri is getting closer to Earth. But don’t be alarmed!
It’s approaching the Earth at about 20 km/s and will be closest in year 29,700 AD.
At this time, it will be about 3.26 light years away. Then, it will start moving further away.
However, this is not an alarming rate of movement since it was first measured in the 1830s.
Reach for the stars
Today, you’ve learned that the closest star to our own is Alpha Centauri. It’s moving closer to us. But not an alarming rate. And finally, it has an exoplanet in the habitable zone of Proxima Centauri.
Space is a remarkable place. We’re learning new things about it everyday. If you want to explore outer space, check out our infographic on our solar system.