Planet found in star system nearest Earth
October 17, 2012
This artist’s impression shows the planet (right) orbiting the star Alpha Centauri B (center), a member of the triple star system that is the closest to Earth and the most brilliant object in the sky in this picture. Alpha Centauri A is shown in bottom left. Our own Sun is the tiny dot in the upper right. (Credit: ESO/L. Calçada)
European astronomers have discovered a planet with about the mass of the Earth orbiting a star in the Alpha Centauri system — the star system nearest Earth. It is also the lightest exoplanet ever discovered around a star like the Sun.
The planet was detected using the HARPS instrument on the 3.6-metre telescope at ESO’s La Silla Observatory in Chile.
Alpha Centauri is one of the brightest stars in the southern skies and is the nearest stellar system to our Solar System — only 4.3 light-years away. It is actually a triple star — a system consisting of two stars similar to the Sun orbiting close to each other, designated Alpha Centauri A and B, and a more distant and faint red component known as Proxima Centauri.
The European team detected the planet by picking up the tiny wobbles in the motion of the star Alpha Centauri B created by the gravitational pull of the orbiting planet. The effect is minute — it causes the star to move back and forth by no more than 51 centimeters per second (1.8 km/hour), about the speed of a baby crawling. This is the highest precision ever achieved using this method.
Alpha Centauri B is very similar to the Sun but slightly smaller and less bright. The newly discovered planet, with a mass of a little more than that of the Earth, is orbiting about six million kilometers away from the star, much closer than Mercury is to the Sun in the Solar System. The orbit of the other bright component of the double star, Alpha Centauri A, keeps it hundreds of times further away, but it would still be a very brilliant object in the planet’s skies.
“This is the first planet with a mass similar to Earth ever found around a star like the Sun. Its orbit is very close to its star and it must be much too hot for life as we know it,” says Stéphane Udry (Geneva Observatory), a co-author of the paper and member of the team, “but it may well be just one planet in a system of several. Our other HARPS results, and new findings from Kepler, both show clearly that the majority of low-mass planets are found in such systems.”
Comments (9)
by Mystic
Obviously, after the singularity everyone who has ever lived will be resurrected, so don’t worry about dying in the mean time.
by Editor
“Citation needed” :)
by melajara
It looks now that orbiting planets are the rule and the exception would be stars WITHOUT any planet. Very comforting.
by Gorden Russell
It was very exciting to find that an Earth-sized planet had been found orbiting Alpha Centauri, I’m certainly glad that Ms. Angelica found this story. It is a shame that this new world is so close to the star. Yet if there is this one, there could be more farther out. Just imagine what it would mean to humanity to have a nearby place to colonize after the Singularity, when we will start building starships. If we can just keep on living until the year 2046, we can see this done.
by GAUSS
We need new fuel sources to make it anywhere. Somebody needs to figure out how to achieve exotic matter in the lab. Quantum mechanics holds the key.
by Arbman
See molten salt Thorium reactors
by trakk
on it
by douglas deveau
33 more years to go. That will make me 83.
by H.K. Fauskanger
We could hope that the planet detected is the hot “Mercury” or “Venus” of this system, and that a more Earth-like planet appears further from the star. But if the first “settlers” from earth are not biological humans, but rather non-biological intelligences that can build whatever bodies they like, even a burning hot planet could be turned into an asset — or actually a home.
It is, in any case, exiting that we have an exoplanet this close. If “only” ten per cent of light speed could be achieved, Proxima Centauri is within reach well within even the lifetime of a biological human. We can already build probes that can function for 40 years or so (the Voyagers, launched in the seventies, are still transmitting information). Ideally we should send a universal constructor that could build additional probes from local matter once it arrived, and survey the system extensively. But then we must wait for the fabled mature phase of nanotechnology.