Thursday , July 29 2021

The frozen super-earth discovered six light years away



Astronomers have found a frozen exoplanet more than three times the mass of the Earth, rotating around a star that is only six light years away. The exoplanet revolves around the star of Barnard, the closest solitary star in the sun.

This makes it the second closest known exoplanet for us. Previously, an exoplanet was found in orbit around the three-star Proxima Centauri.

The exoplanet was found after blackout 20 years of data, including 771 individual measurements, of seven organs. The analysis that led to the discovery is detailed in a study published on Wednesday in Nature magazine.

For years, astronomers thought they would find a planet around the nearby star, but they fled them.

"The biggest" kick "of this discovery is the host star, wrote Paul Butler, co-author and astronomer at the Carnegie Institution for Science. "The star of Barnard is the" big white whale "of planetary hunting."

The planet, known as Barnard's b-star, is probably barely illuminated by its star and slightly cooler than Saturn. Researchers believe it is a frozen desert without liquid water, a hostile environment where the average surface temperature is about-274 degrees Fahrenheit.

The red dwarf star emits only 0.4% of our Sun's radiation, so the planet receives about 2% of the Earth's Sun's intensity. This is due to the fact that the star of Barnard is in the classroom of the homeless dwarf, colder and less massive than our sun. It is also an old star that precedes our solar system.

And to look at it through a telescope, the star seems to move the fastest among the other stars in the night sky. This is because it moves fast in relation to the sun and is the closest star in the sky to us, Butler said.

"The star is named in honor of the great American astronomer Edward Emerson Barnard, who was the pioneer of astral photography and astronomy," said Butler. "He acknowledged that this star had the greatest known movement a century ago."

The planet is about the same orbital distance from its star as Mercury is out of the sun making a full pass around the star every 233 days. This puts it in the star's "snow line" where it's cold enough to freeze the water on solid ice. This area in a planetary system is where the building blocks of the planets are formed, collecting material to become a core. As they move closer to their receiving stars, gathering more material, they become planets.

It is the first time a small and distant planet has been detected by its star using the radial velocity technique, which Butler helped pioneer. This method is sensitive to the mass of the exoplanet and measures the changes in the velocity of the host star. Instruments can be used to detect microscopic wobbles in the star track caused by gravity of the planet.

"I think this discovery shows his strength [radial velocity] a technique for detecting a longer period, small planets that are much more difficult or traceable to missions such as Kepler and TESS, which focus on finding transit exoplanets in shorter orbital periods, "said Johanna Teske, co-author and Hubble at the institute Carnegie for Science, wrote in an email. "This study is a wonderful example of collaboration and coordination between multiple groups and multiple sets of data, something that is not always successful in the search for exoplanets. Only by combining data and collaborating collaborators, this very difficult detection was possible. "

These methods were not always available to astronomers looking for exoplanets. For most of the past hundred years, the only way was the astrometric technique, in which astronomers are looking for the reception star to swing in relation to background stars, said Butler. He worked only for the nearest stars and was achieved by taking pictures of the star and measuring his positions in relation to each other.

"This made Barnard's star the most important star in the sky because it is the closest star in the sky," said Butler.

In the 1930s, the Dutch-American astronomer Peter van de Kamp began an effort to study the Barnard star, who spent most of his 93 years. His allegations of how the planets could fit in orbit around the star were defused and died five months before the first verifiable discovery of an exoplaner in May 1995, Butler said.

"He worked hard to improve the unique technique of the time he had prayed for finding planets and spent decades collecting the data," Butler said. "Van de Kamp is a real champion of extra-solar planets."

Given its proximity to our solar system and its great orbit, future missions and telescopes will be able to provide new ideas for the star of Barnard b.

"Future space telescopes, like WFIRST, could see the reflected light from Barnard's star from the planet and say something about the composition of the surface and / or the atmosphere of the planet," Teske said.


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