A super-Earth orbits a famous star not far from our sun

Since the 1960s, scientists and exoplanet hunters have searched for evidence of planets orbiting one particular star. It’s called Barnard’s star and it’s only six light-years from our sun — a stone’s throw in a cosmic sense. 

Now, an international team of astronomers has managed to discover a possible planet, known as a super-Earth, orbiting the star.

Published in the journal Nature this week, the discovery was made by a team at Hawaii’s W. M. Keck Observatory, using, among other instruments, the observatory’s High-Resolution Echelle Spectrometer (HIRES).  

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

The team, led by Ignasi Ribas of the Institute of Space Studies of Catalonia (IEEC) and Institute of Space Sciences (IEEC-CSIC), dubbed the planet candidate “Barnard’s star b,” or GJ 699 b. 

The super-Earth orbits Barnard’s star every 233 days, and is at least 3.2 times the mass of the Earth (hence the term). 

Although it’s orbiting the closest single star to the sun, the small planet is classified as cold, as it has been determined as sitting in the “snow-line” of the star, and so would likely be a frozen world — in fact, the observatory says the planet’s temperature is likely to be about minus 150 degrees Celsius.

“Though the super-Earth we detected is much too cold to be likely habitable, it does underscore exoplanet statistics that confirm there are more planets in the universe than there are stars, and more potentially habitable Earth-sized planets than grains of sand on all the beaches on our planet,” said co-author Steven Vogt, professor emeritus of astronomy and astrophysics at UC Santa Cruz in a  statement.

So, why are Earth-dwelling scientists so fascinated by this star and its super-Earth in the first place? 

It’s so damn close to us. Even though the team found the planet using the HIRES, you can see Barnard’s star from the Northern and Southern hemispheres with various small telescopes. 

“We knew we would have to be patient. We followed Barnard’s star for 16 long years at Keck, amassing some 260 radial velocities of Barnard’s star by 2013,” said Vogt. “Fortunately, our long-running Keck planet search program gave us the years we needed to gather enough precision radial velocity data with HIRES to begin to sense the presence of a planet.”

“Barnard’s star is among the nearby red dwarfs that represents an ideal target to search for exoplanets that could someday actually be reached by future interstellar spacecraft,” he added.