Astronomers announced Wednesday the discovery of an Earth-size planet around a small red star in our corner of the galaxy.
The new exoplanet, named Ross 128 b, has numerous properties necessary for supporting life: It's a similar size to Earth, it has a rocky surface, and the distance from its star potentially puts it in the "habitable zone"- the area around a star where temperatures allow water to remain liquid on the surface of a planet.
Scientists at the La Silla Observatory in Chile detected Ross 128 b using the High Accuracy Radial velocity Planet Searcher (HARPS), which measures wobbles in stars that have planets orbiting them.
The planet has been able to achieve its temperate climate because it orbits an inactive red dwarf star. These stars output a fraction of the luminescence as our sun, have a much lower surface temperature, and often flare in ways that could sterilize any life on the surface of their planets. But Proxima b's parent star, Proxima Centauri, blasts out a lot of powerful flares, potentially bathing that planet in enough radiation to stunt the emergence and evolution of life, scientists have said.
Earlier this year, by the way, radio astronomers detected a unusual signal that seemed to be emanating from Ross 128.
But the star system this new planet is orbiting, called Ross 128, is much quieter, giving hope it could provide a suitable habit for life.
But what has got people especially excited is its star, Ross 128.
Astronomers estimate that in 79,000 years, Ross 128 b will be our exoplanet neighbor, even closer than Proxima b. And it is just 11 light-years from our solar system, making it the second-closest temperate planet to ever be detected. Where the habitable zone is depends on the star itself: red dwarfs are dimmer and therefore cooler than the Sun, so their habitable zones are shifted closer in than the equivalent zone around our star. Planets close to most red dwarfs are likely to be severely irradiated, causing many scientists to doubt that life could survive on them regardless of whether they're in the habitable zone.
Announcements about exoplanets, those found outside our solar system, seem nearly commonplace in this golden age of discovery for astronomers. The Breakthrough Listen group, as well as the SETI Institute, are now listening for radio signals coming from stars close to Earth. Abel Méndez, the director of the Planetary Habitability Laboratory at Arecibo, nicknamed them "the Weird!" The observing target list included a couple stars that had exoplanets, as well as a few that didn't-including, at the time, Ross 128. The signals had a frequency around 5 gigahertz, right in the middle of the 1-to-15-gigahertz range targeted by typical SETI searches. A subsequent analysis by Breakthrough Listen, accepted for publication in the International Journal of Astrobiology, concluded the signal Méndez's team saw probably came from one of several geostationary satellites in the direction of Ross 128. His team plans to continue observing the system.
We won't know for sure what kind of atmosphere this planet has until we look at it directly, and that may not happen for a while.
Support enables our dedicated journalists to research deeply and bring you original space exploration articles.