Astronomers have confirmed the discovery of the nearest rocky planet outside our solar system using the Spitzer Space telescope. The planet is a mere 21 light-years away, larger than Earth and a potential gold mine of science data. It is also known as HD 219134b.
Planet itself can’t be seen directly, even by telescopes. In the Cassiopeia constellation, near the North Star, this exoplanet which orbits its star is visible to the naked eye in dark skies.
HD 219134b is also the closest exoplanet to Earth to be detected transiting, or crossing in front of, its star and, therefore, perfect for extensive research.
Michael Werner, the project scientist for the Spitzer mission at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California stated that, “Transiting exoplanets are worth their weight in gold because they can be extensively characterized, This exoplanet will be one of the most studied for decades to come.”
The planet, initially discovered using HARPS-North instrument on the Italian 3.6-meter Galileo National Telescope in the Canary Islands, the planet was determined to have a mass 4.5 times greater than Earth, and a speedy three-day orbit around its star.
“Most of the known planets are hundreds of light-years away. This one is practically a next-door neighbor,” said astronomer and study co-author Lars A. Buchhave of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. For reference, the closest known planet is GJ674b at 14.8 light-years away; its composition is unknown.
“Thanks to NASA’s Kepler mission, we know super-Earths are ubiquitous in our galaxy, but we still know very little about them,” said co-author Michael Gillon of the University of Liege in Belgium, lead scientist for the Spitzer detection of the transit. “Now we have a local specimen to study in greater detail. It can be considered a kind of Rosetta Stone for the study of super-Earths.”
HARPS-North also revealed three more planets in the same star system, farther than HD 219134b.