Could There Be Life Near These Two New Super-Earths?
Astronomers have discovered a new crop of super-Earths orbiting a red dwarf star just 11 light-years away.
Two exoplanets have been confirmed, while a third is still awaiting confirmation.
The star, GJ 887, is an M-type red dwarf and appears to be unusually quiet, which is good news in the search for life's building blocks.
Astronomers and their eagle-eyed telescopes have spotted a pair of super-Earth planets just 11 light-years away around the red dwarf star Gliese 887, or GJ 887. A third, unconfirmed planet may orbit the star, too.
The newly discovered exoplanets, GJ887b and GJ887c, are so-called super-Earths, meaning their size ranks roughly between our planet and Neptune.
To get a better look at the system, the team used the European Southern Observatory's HARPS spectrograph in Chile. Astronomers are able to spot the exoplanets using a technique called the doppler wobble.
The gravitational pull of circling exoplanets tugs on a star, causing it to wobble, and astronomers can pick up on these tiny motions. These scientists confirmed their findings by analyzing 20 years of archival data and published their work June 26 in the journal Science.
GJ 887 is the 12th closest planetary system to Earth, according to NASA. The recently discovered planets around it lie just outside the habitable zone, where liquid water—not water vapor or ice—could exist on the surface of a rocky world. Astronomers believe worlds that lie within this region could potentially house life.
With orbital periods lasting 9.8 and 21.8 days, respectively, GJ 887b and GJ 887c are too close to the star to be habitable. Computer simulations revealed that surface temperatures could stretch to around 170 degrees Fahrenheit. The third, unconfirmed planet, however, has a much longer 50-day orbital period and lies just within the habitable zone.
Better yet, the star at the heart of this system has a mass half that of our sun and shines with about one percent of the brightness. It's unusually quiet and almost whisper-still. This means the planets around it aren't constantly bombarded with solar winds barfed out from the star during stellar storms.
“A flaring star with energetic outbursts will strip away an exoplanet’s atmosphere,” astronomer and coauthor Sandra Jeffers, of Göttingen University in Germany, told Forbes. It's yet another indicator that the GJ 887 system could be a good spot to look for the signs of life.
If astronomers can confirm the presence of this third exoplanet, GJ 887 will join the ranks of the TRAPPIST-1 and other exciting nearby systems. In an article accompanying the paper, astronomer Melvyn Davies of Lund Observatory in Sweden, who wasn't affiliated with the research, said it "could become one of the most studied planetary systems in the Solar neighborhood."
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