The single nearest star to the Sun—which is to say, the closest star moving independent from a star system—has at least one exoplanet, according to a team of astronomers that recently scrutinized the heavenly body.
The team’s research—published today in Astronomy & Astrophysics—describes conclusions made from five years of observational data taken with the European Southern Observatory’s Very Large Telescope at Chile’s Paranal Observatory.
The little world orbits Barnard’s star, a red dwarf about six light-years from Earth. Barnard’s star is a dim, cool star about one-seventh the mass of our Sun. Unlike the nearest star to the Sun (Proxima Centauri, a little over four light-years away in the Alpha Centauri star system), Barnard’s star zips through the cosmos alone. As EarthSky points out, Barnard’s star is much less powerful than the Sun; if we orbited that star instead of the Sun, life as we know it would not be possible.
The same could be said for the spunky exoplanet, but in the opposite direction as a thermometer reads. The star—dubbed Barnard b—is about twenty times closer to its host star than Mercury is to our Sun, and whips around Barnard’s star in just over three Earth days. Given its celestial proximity, the exoplanet is understandably piping, with a surface temperature around 257° Fahrenheit (125° Celsius).
“Barnard b is one of the lowest-mass exoplanets known and one of the few known with a mass less than that of Earth,” said Jonay González Hernández, a researcher at the Instituto de Astrofísica de Canarias in Spain and the study’s lead author, in an ESO release.
Barnard’s star was previously suspected to host exoplanets in its orbit—there was promising evidence in 2018, but no certain confirmation—until now.
The team was looking for exoplanets orbiting Barnard’s star that may exist within the habitable (or “Goldilocks”) zone, a distance from a host star where liquid water can exist on a planet’s surface. It does not, so life as we know it can’t exist on the exoplanet.
“The discovery of this planet, along with other previous discoveries such as Proxima b and d, shows that our cosmic backyard is full of low-mass planets,” said study co-author Alejandro Suárez Mascareño, a researcher also at the Instituto de Astrofísica de Canarias, in the same release.
In its new paper, the team also stated that there is evidence of at least three more exoplanet candidates around Barnard’s star, though more observations will be necessary to confirm whether any of those candidates are actual exoplanets.
The next-generation Extremely Large Telescope, alongside missions like the Webb Space Telescope and the Transiting Exoplanet Survey Satellite (TESS) will hopefully yield more discoveries of these not-so-distant alien worlds.
