Science

Super-Earth exoplanet found around closest single star to the Sun

Super-Earth exoplanet found around closest single star to the Sun

Barnard's star, which is just six light-years away, moves in Earth's night sky faster than any other star.

Artist's impression of Barnard's Star's planet under the orange tinted light from the star.

But the search for evidence of planets around this famous red dwarf star over the past 50 years has been unsuccessful, until now.

Barnard's Star has always been "the great white whale" of exoplanet hunting, said Carnegie astronomer Paul Butler, a co-author on the Nature paper.

"We couldn't get a single experiment that would detect it unambiguously, so we had to combine all the data very carefully", said the Queen Mary University of London astronomer. But the methods we've used to detect majority are biased toward finding large planets that orbit close to their host stars. So, it's distinctly outside the habitable zone with a surface temperature of -170 degrees Celsius (-274 degrees Fahrenheit). Today, many planetary scientists believe that life on it is impossible because of the hectic nature of red dwarf, whose surface is constantly having flash is able to "break" the atmosphere of the planet.

Part of the challenge of finding the planet comes from the method that astronomers used: radial velocity (RV). They used the radial velocity method to measure the star's subtle back-and-forth wobble caused by the gravitational tug of an orbiting planet. Astronomers have been measuring minuscule characteristics of the star for decades, searching for signs of orbiting planets, and over the years, hints of a possible world tugging on the star have been gleaned here and there-but nothing was ever considered conclusive. When the star moves away from the Earth, its spectrum redshifts; that is, it moves towards longer wavelengths.

"We used observations from seven different instruments, spanning 20 years of measurements", Ignasi Ribas, the team's lead scientist (Institute of Space Studies of Catalonia and the Institute of Space Sciences, CSIC in Spain), said in a statement.

Stan Lee death: Stars pay tribute to Marvel's 'creative genius'
He was a childhood inspiration, an instructor to me when I was just getting started and a genuinely sweet man. This is what people forget: Fantastic Four #1 predated Marvel officially donning the moniker Marvel Comics .

Rowan Lippert is a seasoned journalist with 15 years experience as a reporter.

The worldwide team of astronomers behind the discovery were also the same team who in 2016 spotted Proxima Centauri b; the closest known exoplanet to us only four light years away. It is worth noting, however, that the measurements place the planet at a similar period to van de Kamp's claims in the 1960s. Most exoplanets, including the thousands identified by NASA's recently retired Kepler space telescope, were found using the "transit" technique: looking for a periodic dip in starlight as a planet passes in front.

While Barnard's Star is the closest single star to our solar system, humans will never reach the planet anytime soon with our current technology. One of the largest observing campaigns to date using data from a world-wide array of telescopes, including ESO's planet-hunting HARPS instrument, have revealed this frozen, dimly lit world.

The center of the image shows Barnard's Star captured in three different exposures.

From this orbital information, the team calculates the planet must weigh at least 3.2 times as much as Earth. It would be as close to its parent star as Mercury is to our own sun - but because Barnard's Star is a dim red dwarf, surface conditions would be far too chilly for life as we know it.

"The star is named in honor of the great American astronomer Edward Emerson Barnard, who was a pioneer of stellar photography and astrometry", Butler said. "But in the United States, they are also developing WFirst - a small telescope that's also used for cosmology", said Dr Anglada Escudé.