Cold ‘super-Earth’ exoplanet discovered orbiting nearby star

Cold ‘super-Earth’ exoplanet discovered orbiting nearby star

Artist's impression of Barnard's Star's planet under the orange tinted light from the star. Bernard's star, just six light years from Earth, is smaller and older than our Sun and among the least-active known red dwarfs. That's hard to do because, viewed from Earth, the planet is close to the star and swamped by its glare. Alpha Centauri's triple-star system (including Alpha Centauri A and B, plus Proxima Centauri) are the only stars nearer.

Barnard's Star, a small red dwarf, has always been a prime planet-hunting target.

This chart shows the location of Barnard's Star within the constellation of Ophiuchus, straddling the celestial equator, and marks most of the stars visible to the unaided eye on a clear dark night.

First reported in the journal "Nature", the new planet orbits Barnard's star every 233 days.

"There´s not so many stars in our immediate neighbourhood".

Known as Barnard's star b, its surface temperatures are estimated at minus 150C. Knowing that we have one of these unusual exoplanets so nearby could allow us to get to know this planetary species a little better. When the planet moves closer to the star, the starlight is shifted toward shorter, blue wavelengths (called blueshift) and when the planet moves farther away from the star, the starlight shifts toward longer, red wavelengths (called redshift).

Red dwarfs are far smaller and cooler than our own star, and thus emit far less heat.

As scientists hope that the first pictures will be received already in the running GAIA mission, and the telescope WFIRST and "James Webb", which NASA will take into space early next decade. The temperature of Barnard star b is far too cold to support any life on that.

Ribas and his team used 800 different observations of Barnard's Star to drive down the uncertainty that the planet existed. With the Doppler effect, as a planet orbits a star, the planet's gravitational pull causes its star to wobble a little bit.

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"We knew we would have to be patient".

For most of human history, it was thought that the positions of the stars were fixed, but to modern astronomers, Barnard's Star is virtually zipping across the sky. It turns out there are some very close to Earth, though.

One of them was the new state-of-the-art planet-hunting instrument Carmenes at the Calar Alto Observatory in Spain. The information was figuratively stitched together into a dataset that is counted among the most extensive used for detecting planets. "The combination of all data led to a total of 771 measurements - a huge amount of information!" For most of the past hundred years, the only way was the astrometric technique, in which astronomers look for the host star to wobble relative to background stars, Butler said.

That seemed to be the case when a team of researchers started checking archival data for Barnard's star images.

Observing Barnard's star continues and the experts and fans of astronomy all over the world.

Dr. Anglada-Escudé and co-authors used the radial velocity method during the observations that led to the discovery of Barnard's star b. This means that astronomers are getting better at finding these kinds of planets outside our solar system.

"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.

Astronomers have, since 1997, collected a large number of measurements on the oscillation movement of the star.

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