Both have water, but no current mission or conceivably could yet find out if these worlds are habitable, scientists warn.
Thanks to the successful Kepler space telescope, a team of astronomers discovered the presence of five extrasolar planets around a star, Kepler-62, 1,200 light years from Earth, and two of those worlds are particularly interesting because they could be made of rock or ice, have a size slightly over our planet (1.4 and 1.6 times the Earth’s radius), and the distance to orbiting its star, it would receive an amount similar to radiation they receive from the Sun Venus and Mars
They are in what scientists call the habitable zone, ie the distance to the star in which a body could have liquid water. NASA scientist William J. Borucki and colleagues explain the finding in the journal Science. It is the first extrasolar planet found in habitable zone, since more than a year ago found another in that situation orbiting a Sun-like star, Kepler-22, but its radius is 2.4 times the Earth and its composition is an uncertainty.
Little by little, scientists are unraveling how not only is the population of planets around other stars (whose very existence was unknown less than 20 years), but are closing in order to find the worlds most similar to ours its composition and conditions.
Boruki team “stands out in his article that he does not know if his new find has water, air or a solid surface,” says the specialist Richard A. Kerr in Science, focusing on one of the two Earth-like worlds discovered is especially interesting.
“Moreover, no current mission, planned or maybe even conceivably could prove that this exoplanet is habitable,” he adds. The goal of Kepler, remember, is to determine how common are planets similar in size to Earth in orbit Earth in the habitable zone of stars like the Sun “and were discovered more than a hundred terrestrial and size as small as the moon. “
The planets Kepler-62f and Kepler-62e are the outer two of the five discovered around this star. “So we can say, given its radius and orbital period, these two planets are most similar objects to the Earth we have found,” says one of the astronomers on the team, Justin Crepp, University of Notre Dame in USA.“Theoretical models of Kepler-62e and Kepler-62f suggest that both planets could be solid: a composition either rocky or icy water, for the most part,” the researchers write in their Science paper.
The five planets take to meet your sun around six days (the closest to the star and therefore too hot) to nine months. The habitable zone, said Kerr is the orbital distance range within which work the greenhouse effect on a planet that has an atmosphere of nitrogen, carbon dioxide and water, with a maximum outer boundary distance to the star from which carbon dioxide would freeze and indoor atmosphere in which the excess would overheat, Venus. Of the five exoplanets discovered now, only Kepler-62f, with 1.4 times the Earth’s radius is strict in this area range, while Kepler-62e, the closer to the star, escapes a little out of the area defined .