A supertierra orbits Barnard's star

A supertierra orbits Barnard's star https://i1.wp.com/www.eresviral.com/wp-content/uploads/2018/11/Una-supertierra-orbita-a-la-estrella-de-Barnard.jpg?fit=260%2C146&ssl=1

A supertierra orbits Barnard's star







A planet has been detected orbiting the Barnard star, an object only 6 light-years away. This advance, released in an article published in the journal Nature, is the result of the Red Dots and CARMENES projects, whose search for local rocky planets has already discovered a new world orbiting our nearest neighbor, Proxima Centauri.



The planet, designated as the star of Barnard b, is the second known exoplanet closest to Earth. The data obtained indicate that the planet could be a super-earth, has a mass of at least 3.2 times that of Earth, and orbits its host star in approximately 233 days. The star of Barnard, the star that shelters the planet, is a red dwarf, a cold star, of low mass, that illuminates in a very weak way this newly discovered world. The light from Barnard's star provides your planet with only 2% of the energy that Earth receives from the Sun.



Despite being relatively close to its star, at a distance of only 0.4 times that which separates the Sun from Earth, the exoplanet is near the snow line, the region where volatile compounds such as water can condense into solid ice This icy and shadow world could have a temperature of -170 ° C, making it inhospitable to life as we know it.



Called thus by the astronomer EE Barnard, the star of Barnard is the unique star nearer the Sun. While the star in itself is old (it is probably twice the age of our Sun), and relatively inactive, it is also the star with the fastest apparent movement of the sky. Superterras are the most common type of planet that forms around low-mass stars like Barnard's star, giving credibility to this newly discovered planetary candidate. On the other hand, current theories of planetary formation predict that the snow line is the ideal place for the formation of these planets.







The single star closest to the Sun houses an exoplanet at least 3.2 times as massive as Earth, a so-called super-Earth. Using data from a set of telescopes around the world (including ESO's HARPS planetary hunter instrument), the existence of this icy, dimly lit world has been revealed. The newly discovered planet is the second known exoplanet closest to Earth. Barnard's star is the fastest star in the night sky. This image shows an artistic illustration of the surface of the planet. (Credit: ESO / M. Kornmesser)



Previous searches of a planet around Barnard's star have had disappointing results, but this recent breakthrough has been possible by combining the measurements of several high-precision instruments mounted on telescopes around the world.



"After careful analysis, we are convinced 99% that the planet is there," says the scientist who leads the team, Ignasi Ribas (Institute of Space Studies of Catalonia and Institute of Space Sciences, CSIC, in Spain). "However, we will continue to observe this fast star to exclude possible, but unlikely, natural variations of stellar luminosity that can be mistaken for a planet."



Among the instruments used are the famous planet hunter HARPS and the UVES spectrograph, both of ESO. "HARPS played a vital role in this project. File data from other teams were combined with new and overlapping measurements of the Barnard star from different facilities, "said Guillem Anglada Escudé (Queen Mary University of London), a scientist who co-leads the team that has obtained these results. "The combination of instruments was key to be able to corroborate our results".



The astronomers used the Doppler effect to detect the exoplanet candidate. While the planet orbits the star, its gravitational pull causes the star to wobble. When the star moves away from the Earth, its spectrum shifts to red (redshift); that is, it moves towards longer wavelengths. In the same way, the star's light travels towards shorter, bluer wavelengths when the star moves towards the Earth.



Astronomers take advantage of this effect to measure with amazing accuracy the changes in the speed of a star due to an exoplanet that orbits. HARPS can detect changes in the velocity of the star as small as 3.5 km / h (a pace similar to the one we use when walking). This exoplanet search technique is known as the radial velocity method and has never before been used to detect a similar super-Earth-type exoplanet in such a large orbit around its star.



"We have used observations from seven different instruments, spanning 20 years of measurements, making this one of the largest and most extensive datasets used for precise studies of radial velocity," explains Ribas. "The combination of all the data led to a total of 771 measurements, a lot of information!"



"We have all worked very hard in this advance," concludes Anglada-Escudé. "This discovery is the result of a great collaboration organized within the framework of the Red Dots project, which included contributions from teams from all over the world. Follow-up observations have already been launched in different observatories around the world. " (Source: ESO)

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