GJ674b, discovered in 2007, is the closest known planet to Earth at only 14.8 light-years away. This one is practically a next-door neighbour, ‘ said Lars A. Buchhave, an astronomer at the Harvard-Smithsonian Center for Astrophysics.
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The planet is detailed in a study accepted for publication in the journal Astronomy & Astrophysics. The fastest spacecraft in the Solar System – NASA’s Juno probe – is now traveling at nearly 86,000 miles (138,000 kms) per hour relative to the Earth. But before you pack your bags, make sure you can withstand completely scorching heat: The super-Earth orbits super-close to its star, completing a revolution in just under a week.
If it is a rocky world like Earth, then its surface gravity may be as much as twice that we experience on Earth. Since stars themselves evolve over time, Kepler-452b presently receives about 10 percent more energy from its sun than Earth receives from ours – and that in turn would have its own effects on the surface -and atmospheric- conditions that exist on the planet. Measuring how much the host star dimmed during a transit enabled astronomers to calculate the planet’s size.
There is one exoplanet that’s even closer than HD 219134b.
The planet was first discovered by the HARPS-North, the University of Geneva’s planet-hunting device on the 3.6-metre TelescopioNazionale Galileo in the Canary Islands.
The planet has a mass 4.5 times that of Earth’s and is approximately 60% larger, putting it in a class of exoplanets – a term for planets that orbit a star, stellar remnant or brown dwarf beyond the solar system – known as “super Earths”.
The Spitzer Space Telescope has found a rocky planet just 21 light years from Earth. The star lies just off the “W” shape of the constellation Cassiopeia and can be seen with the naked eye in dark skies. Its existence is implied by its shadow-casting orbit by way of the glow of its solar, which was picked up by NASA’s Spitzer Space Telescope. That revealed the planet’s mass and orbit; follow-up observations with Spitzer’s infrared instrument revealed the planet’s size, which combined with the mass, allows us to deduce the density – about six grams per cubic centimeter, which confirms it as a rocky planet like Earth.
The closest known exoplanet, the composition of which remains unknown, is almost 15 light-years away. Based on changes in the colours of light detected by telescopes each time that happens, astronomers hope to be able to learn about the chemicals in the planet’s atmosphere, if it has one.
While HD 219134b is the closest confirmed rocky and transiting exoplanet, it’s not the nearest alien world of any type.
Two are relatively small and not too far from the star.
A giant planet with 62 times the mass of the Earth, orbiting about twice as far from its star as the Earth is from the Sun, once every 1,190 days.
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This artist’s impression shows the silhouette of a rocky planet, dubbed HD 219134b, as it passes in front of its star.
