Astronomers have discovered a planet several times larger than Earth and covered with ice near the closest single star Barnard's star.
Barnard's Star is a dim and old red dwarf that was discovered only 100 years ago and would not have received much attention if it was not only six light-years from Earth. This is the closest single star to us, only the alpha Centauri triple system is closer to us, so astronomers have been studying it quite actively and since the 1960s have been trying to find out whether it has planets - possible targets for future interstellar missions.
This search has brought results only now: an article has been published in the journal Nature, the authors of which report the discovery of an exoplanet near Barnard's star - the super-Earth GJ 699 b. Its mass is estimated at 3.2 Earth masses, and it makes a full annual revolution in orbit in 230 days. The planet is located on the far edge of the red dwarf's "habitable zone", and its surface is most likely covered with ice.
A large international team of scientists led by Spanish astrophysicist Ignasi Ribas used the HIRES spectrometer at the W. M. Keck Observatory in Hawaii to make observations. Over the course of 16 years, about 260 of the most accurate measurements of the motion of Barnard's star were carried out, in addition, they were added to the measurements obtained by the telescopes of three more observatories (ESO, Las Campanas and Lickskoy).
The icy surface of the super-earth GJ 699 b under the orange light of a dim star: an artist's view / © ESO, M. Kornmesser
The fact is that Barnard's star moves across the sky faster than any other (not counting the Sun), which greatly complicates its study. However, a large array of collected data (more than 770 measurements in total) gave fairly accurate numbers that indicated the oscillations of Barnard's star caused by the regular orbiting of a massive body around it. Additional observations confirmed the existence of the exoplanet.
Comparison of distances from the Sun to the nearest stars / © IEEC, Science-Wave, Guillem Ramisa
Observations of Barnard's Star are continued by experts and fans of astronomy all over the world. We can already confidently say that the closest single star of large planets - gas giants - does not exist. However, GJ 699 b may not be the only one - and it has neighbors about the size of the Earth or even less.