Astronomers have found a frozen exoplanet more than three times the mass of the Earth, surrounded by a star that is only six light-years away. The exoplanet is orbiting Barnard's star, the nearest lone star to our sun.
This makes us the closest known exoplanet. Previously, the explosion was found in orbit in the Prokima Centauri system with three stars.
The exoplanner was found after connecting 20 years of data, including 771 individual measurements, of seven instruments. The analysis that led to the discovery is detailed in a study published Wednesday in the journal Nature.
For years, astronomers thought they would find a planet around a nearby star, but he avoided them.
"The biggest impact on this discovery is the host star," wrote Paul Ellner, co-author and astronomer at the Carnegie Institute of Science. "Barnard's star is a" big white whale "in hunting the planet."
The planet, known as Barnard's star b, is probably a slightly illuminated star and slightly colder than Saturn. Researchers believe it is an icy desert without liquid water, an enviromental environment in which the average surface temperature is about minus-274 degrees Fahrenheit.
The red dwarf star itself emits only about 0.4% of our sunshine, so that the planet receives about 2% of the intensity Earth receives from its sun. This is because Barnard's star is in the class of M dwarf stars, cooler and less massive than our sun. It is also an old star leading our solar system.
And to look through the telescope, the star seems to be moving fastest among other stars in the night sky. This is because it is moving fast in relation to the Sun, and that is the closest star in the sky for us, Butler said.
"The star has been named in honor of the great American astronomer Edward Emerson Barnard, who was the pioneer of star photography and astrometry," Butler said. "He recognized that this star had the greatest known movement a century ago."
The planet is about the same orbital distance from its star as Merkur is from our sun, making it a full passage around the star every 233 days. This puts him in the "snow line" of the star, where it is cold enough to freeze water into solid ice. This region in the planetary system is the place where the planets are thought to form, collecting material to become nuclei. As they migrate closer to home stars, gathering more material, they become planets.
For the first time, this small and farther than its star planet was discovered using the radial velocity technique Butler helped pioneers. This method is sensitive to the mass of the ecoplanet and measures changes in the speed of the host. Instruments can be used to detect small wrinkles in the orbit of a star that is caused by the gravity of the planet.
"I think this discovery shows the power [radial velocity] a long-range detection technique, small planets that are much more difficult or can not be detected using missions like Kepler and TESS, which focus on finding transit exoplanets in shorter orbital periods, "says Johanna Teske, co-author of studies and Hubble Fellows in Carnegie Institute of Science, he wrote in an e-mail. "This study is a wonderful example of cooperation and coordination in multiple teams and multiple sets of data, something that is not always successful in exploring the exoplanet. Just by combining data and working together, this was a very demanding discovery. "
These methods were not always available to astronomers looking for exoplanets. Most of the last hundreds of years, the only way was an astrometric technique, in which astronomers are asking the star of the host to wake up against the background stars, Butler said. It worked only for the closest stars and was achieved by photographing the star and measuring its positions in relation to each other.
"This made Barnard's star the most important star in the sky because it is closest to a star in the sky," Butler said.
During the 1930s, the Dutch-American astronomer Peter van de Kamp began his search for Barnard's star, which lasted for most of his 93 years. His claims that the planets could fit into orbit around the star were killed and died five months before the first explanted state was discovered in May 1995, Butler said.
"He worked hard to improve the only technique that at that time had a prayer for finding the planets and for decades collected data," Butler said. "Van de Camp is a real pioneer on extrasolar planets."
Given its proximity to our solar system and its long orbit, future missions and telescopes will be able to provide new information on Barnard's star b.
"Future cosmic telescopes like VFIRST could observe the reflected light from the Barnard star from the planet and thus tell us something about the composition of the surface and / or the atmosphere of the planet," Teske said.