NASA confirms the closest "super-Earth" outside the Solar System
The US National Aeronautics and Space Administration (NASA) confirmed that planet HD 219134b, 21 light-years from Earth, is the closest rocky planet outside the Solar System.
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Using NASA's Spitzer Space Telescope, scientists discovered the nearest rocky planet outside our Solar System, 21 light-years away. It is larger than Earth and has been named HD 219134b.
HD 219134b's orbit is too close to its parent star to sustain life. We can't observe HD 219134b directly with a telescope. However, the star it orbits is visible to the naked eye at night, in the constellation Cassiopeia, near the Big Dipper.
HD 219134b is also the closest planet to Earth to be discovered using photometry. When the planet passes in front of its parent star, it blocks out some of the star's light. Telescopes look for small changes in the star's brightness to detect the new planet.
"The exoplanet will be one of the most studied in the next few decades," NASA quoted Michael Werner of the Jet Propulsion Laboratory (JPL) in Pasadena, California (USA) as saying on July 30.
Scientists first spotted HD 219134b using the HARPS-North instrument on the Galileo National Telescope in the Canary Islands, Italy. HARPS-North uses a method called the “radial velocity technique,” which calculates a planet’s mass and orbit based on the gravitational pull it exerts on its parent star. It is also the subject of a study published in the journal Astronomy & Astrophysics.
Infrared measurements from the Spitzer Space Telescope show that HD 219134b is a rocky planet 1.6 times the size of Earth, with a density of 6 g/cm3.
Rocky planets larger than Earth, like HD 219134b, are known as super-Earths. They are increasingly being discovered in the universe.
"Thanks to NASA's Kepler mission, we know super-Earths are everywhere in the galaxy, but we know very little about them. Now we have a model planet to study in more detail," said Michael Gillon of the University of Liege, Belgium.
According to VnExpress