A potentially rocky super-Earth orbits one of our closest stellar neighbors, Barnard’s star, only 6 light-years away.
Barnard’s star is a low-mass red dwarf star located in the constellation Ophiuchus.
At nearly 6 light-years away, the star is the next closest star to the Sun after the Alpha Centauri triple stellar system.
“Barnard’s star is an infamous object among astronomers and exoplanet scientists, as it was one of the first stars where planets were initially claimed but later proven to be incorrect. Hopefully we got it right this time,” said Dr. Guillem Anglada-Escudé, an astronomer in the School of Physics and Astronomy at Queen Mary University of London.
The newly-discovered planet, named Barnard’s star b, is a ‘super-Earth’ with a mass of 3.2 times that of Earth.
It orbits around its parent star once every 233 days and lies at a distant region from the star known as the ‘snow line’ — this is well beyond the habitable zone in which liquid water, and possibly life, could exist.
The surface temperature of Barnard’s star b is estimated to be around minus 274 degrees Fahrenheit (minus 170 degrees Celsius) meaning it is likely to be a frozen world which is uninviting to Earth-like life.
However, if the planet has a substantial atmosphere the temperature could be higher and conditions potentially more hospitable.
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 technique detects wobbles in a star which are likely to be caused by the gravitational pull of an orbiting planet.
These wobbles affect the light coming from the star. As the star moves towards the Earth its spectrum appears slightly shifted towards the blue and, as it moves away, it is shifted towards the red.
“After a very careful analysis, we are over 99% confident that the planet is there, since this is the model that best fits our observations. However, we must remain cautious and collect more data to nail the case in the future,” said Dr. Ignasi Ribas, a researcher at the Institut d’Estudis Espacials de Catalunya and the Institute of Space Sciences, Spain.
The discovery is reported in the journal Nature.
Source: Sci News