Another “Earth” has been discovered

It has a diameter a little bigger than the Earth and is to orbit a star similar to the Sun extraordinarily. To complete the picture, the distance between the planet and parent star is the same as that which separates the earth from the sun. The planet was discovered by NASA’s Kepler mission, therefore, it is in the habitable zone.
The hunt for exoplanets systems which might be considered the facsimile dell’accopiata Earth-Sun is becoming tighter. It ‘a continuous exciting race between the various research groups that sharpen their weapons, made of telescopes, room images, spectrographs, algorithms, and obviously a lot of work, to approach the coveted goal. Only a few days ago we reported the discovery of an exoplanet the size of Jupiter orbiting a Sun-like star.

Artistic representation of the Kepler 452b surface


Credit: SETI Institute / Danielle Futselaar

These days NASA, during a press conference announced the discovery of a planet, with a diameter less than twice that of Earth and that is to orbit a star similar to the Sun. And, to complete the picture, the distance between planet and parent star is the same as that which separates the earth from the sun. The planet is therefore in the habitable zone.
The discovery was made in the context of the new catalog released by the team of the Kepler mission, which adds 500 new candidate exoplanets to nearly 4200 already identified by the observatory orbiting NASA in four years, and despite its recent operational problems.
“This catalog contains our first analysis of all data from Kepler, as well as an automated evaluation of these results,” says Jeffrey Coughlin, a scientist at the SETI Institute who led the work to build the new catalog. “Techniques more efficient analysis will allow astronomers to better determine the number of small and cold planets that are the best candidates to host life.” The Kepler space telescope identifies possible planets by observing the periodic decreases in the brightness of stars. However, confirmation that these phenomena are actually related to the transit of planets in front of their parent star requires observations from other instruments, usually looking for small shifts in the movement of the stars. It should be remembered that the vast majority of candidates discovered by Kepler have turned out to be actually planets.
The new catalog includes 12 candidates, whose diameter is less than twice that of Earth, orbiting in the so-called habitable zone of their star. In this area the flow of energy emitted from the star is such as to permit the existence of liquid water if present on the surface of a planet. Among these candidates, Kepler 452b is undoubtedly the most interesting, because it orbits a star with very similar characteristics to the Sun: it is compared to only 4 percent more massive and 10 percent brighter. Plus Kepler 452b orbits its star at a distance of about 150 million kilometers, the same that separates the Earth from the sun.
“Although he has completed the acquisition of scientific data now for a couple of years, the Kepler mission continues to reserve exciting new surprises,” said Alessandro Sozzetti, researcher INAF-Astrophysical Observatory of Turin. “Among the candidates transiting planets discovered since the last data analysis of the mission, Kepler-452b is not only the right distance, but it was finally identified around a star very close to the Sun as features. In terms of similarity to our Earth, Kepler-452b beats Kepler-22b, the first ‘twin’ of our planet discovered by Kepler four years ago. The process of data validation Kepler unfortunately only allows you to verify that the object is not an ‘impostor’ (or false positive) and to accurately determine the radius. To understand exactly what its composition, and finally determine whether it is really a kind of rocky planet like our Earth, we need a measure of its mass (which combined with a radius measurement it gives access to an estimate of the density of the object ), which can only take place indirectly by measuring the periodic variations in the stellar motion induced by the planet. For Kepler-452b, the amplitude of such motion is probably of the order of 10 cm / s, an order of magnitude less than the state of the art (1 m / s) today reached with tools such as the one INAF HARPS-N the National Telescope Galileo. The actual measurement of the mass of Kepler-452b is therefore not easy to make a goal! It will require technological innovations to push the accuracy of the measurements beyond the limits of today. Additional benefits will come in the future decade of the detectability of transiting planets like Kepler-452b but around the brightest stars and closer to the Sun than those observed by Kepler, which is provided by PLATO mission of ESA, whose launch is planned in 2024 “.

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