A super-Earth found in our stellar back yard

Barnard's Planet

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

Barnard's star is a low-mass red dwarf star located in the constellation Ophiuchus.

Astronomers have discovered a frozen and dimly lit planet, dubbed 'Super-Earth, ' orbiting the closest solitary star to the Sun, a breakthrough that could shine a light on Earth's nearest planetary neighbours. That's much closer than Earth to the Sun (about 0.4 times the distance), but Barnard's Star is such a dim bulb that the planet only receives about 2% as much light as Earth does, so it's very, very cold. Lacking atmosphere, its temperature is likely to be about minus 170 degrees Celsius, which makes it unlikely that the planet can sustain liquid water on the surface. After dismissing evidence for an exoplanet orbiting this star in the 1970s, the team now says there's a very good chance Barnard's Star does indeed host a super-Earth.

It's so damn close to us.

"We knew we would have to be patient". This is because Barnard's Star is a dwarf star.

Two decades' worth of data went into the discovery, all of it having been gathered by seven instruments. One of those stars, Proxima Centauri, is orbited by a small planet, but the star's tendency to spew flares of deadly radiation means its planet is unlikely to be habitable.

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

Analysis of Barnard's star suggested it rotated about every 140 days (this can also cause changes, as more or less active regions of the star rotate in and out of view). From 1963 to 1972, the star was widely believed to host one or more gas giants, accounting for some of the earliest extrasolar planet claims that received widespread attention. As it moves towards Earth its light appears shifted towards the blue part of the spectrum and, as it moves away, it appears shifted towards the red. This is because it's moving quickly in relation to the sun, and it's the nearest single star in the sky to us, Butler said. Knowing the star's mass, we can then determine the planet's mass of 3.2 times the Earth's (this is found by how much the planet tugs on the star). "Barnard's star is the "great white whale" of planet hunting".

Observations of the planet indicate it is a rocky world.

What was going on? van de Kamp's observations were made using a large refracting telescope, and astronomers eventually realised that the telescope's main objective lens had been cleaned and modified several times during the decades of his study. Mini-Neptunes and super-Earths are the most common kind of planet found orbiting other stars.

This wealth of data provided the extraordinary accuracy needed to identify the influence of the planet with near certainty. "This is the result of a large collaboration organized in the context of the Red Dots project, which is why it has contributions from teams all over the world, including semi-professional astronomers", concluded Guillem Anglada-Escudé from Queen Mary University of London, who co-led the effort.

He added: "Difficult detections such as this one warrant confirmation by independent methods and research groups. a signal for the planet might be detectable in astrometric data - precision measurements of stellar positions - from the Gaia space observatory that are expected to be released in the 2020s". "Van de Kamp is a true pioneer in extrasolar planets".

Despite this particular planet's seeming inhabitability, the reported detection raises hopes that astronomers could get a closeup look at the type of exoplanet considered most likely to have conditions conducive to life.

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