The planet, actually an extrasolar planet (often shortened to exoplanet) because it orbits a star other than the Sun, was discovered with the use of the European Southern Observatory.
On Tuesday October 16, 2012, a European team announced the existence of the exoplanet Alpha Centauri Bb, which orbits about the star Alpha Centauri B. It orbits very close to its parent star, even closer than Mercury orbits the Sun.
Alpha Centauri Bb is an extrasolar planet orbiting the K-type star Alpha Centauri B. The exoplanet is about 4.37 light-years from Earth. Even at that distance, which is small in cosmic terms, it would still take tens of thousands of years to send a probe there under our current technological skills.
However, this discovery will likely increase further interest in exploration outside of our solar system -- into interstellar space. Read the Space.com article Nearby Earth-Sized Alien Planet Could Spur Interstellar Exploration for additional information.
Alpha Centauri Bb is located in the southern constellation of Centaurus. As of its discovery, Alpha Centauri Bb, is the closest exoplanet to Earth ever discovered. Astronomers also state that it is the least massive known planet to orbit a star similar to the Sun.
The planet is not in the habitable zone (sometimes called the Goldilocks zone [aka: not too far away from its parent star, not too close, but just right]) because it orbits too close to its star, only 0.04 astronomical unit (AU) from its parent star, where 1 AU is the average distance between the Earth and the Sun, about 149,597,871 kilometers (93 million miles)
Alpha Centauri Bb makes one orbit every 3.236 (Earth) days. At such a short distance from its star, it is unlikely any life exists on the planet (at least any life that we can imagine). Its maximum surface temperature (about 1,200 degrees Celsius) is much hotter than the maximum temperature on the planet Venus (about 462 degrees Celsius), which is the hottest planet in our solar system (even hotter than Mercury, the closest planet to the Sun).
Learn more information about "Alpha Centauri B" at the Wikipedia.com.
The image provided at the top of this article is captioned: "This artist’s impression shows the planet orbiting the star Alpha Centauri B, a member of the triple star system that is the closest to Earth. Alpha Centauri B is the most brilliant object in the sky and the other dazzling object is Alpha Centauri A. Our own Sun is visible to the upper right. The tiny signal of the planet was found with the HARPS spectrograph on the 3.6-metre telescope at ESO’s La Silla Observatory in Chile."
This image was produced by the European Southern Observatory (ESO). Its website states: "All ESO still and motion pictures are released under the Creative Commons Attribution 3.0 Unported, unless the credit byline indicates otherwise." Source" http://www.eso.org/public/images/eso1241b/; Author" ESO/L. Calçada/N. Risinger (skysurvey.org)
Page two concludes with a statement from NASA.