Scientists have found two super-Earths orbiting a nearby star with another potential world possibly located in the habitable zone. GJ 887 (also known as Gliese 887) is the brightest red dwarf star in the sky and is the twelfth-closest star to us as it is located just 10.7 light-years away from Earth.
Since it is almost half of our sun’s mass, Gliese 887 is the heaviest red dwarf star within 20 light-years from us and it could provide astronomers the best opportunity to study the atmospheres present on other worlds.
It wasn’t an easy task finding planets orbiting Gliese 887 as Sandra Jeffers, who is an astrophysicist at the University of Göttingen in Germany as well as the lead author of the study, explained to Space.com, “we've been looking for exoplanets orbiting Gliese 887 for nearly 20 years, and while we saw hints of a planetary signal, it wasn't strong enough to convince ourselves that it was a planet.”
Scientists spent 80 nights in 2018 observing Gliese 887 by using the High Accuracy Radial velocity Planet Searcher (HARPS) instrument at La Silla Observatory in Chile. They took that data along with previous measurements of the star that had been gathered over a time frame of almost two decades. They focused on finding wobbles from the star that would have been caused by gravitational pulls from planets that were orbiting it. And that’s when they discovered two super-Earths that have been named Gliese 887 b (which is about 4.2 times the mass of Earth) and Gliese 887 c (7.6 times the mass of Earth).
The researchers believe that there is a third planet that’s located further away from the star than the other two worlds but it hasn’t been confirmed yet. And while the first two planets are probably too hot to sustain any life, the third unconfirmed planet could be located in the habitable zone of the star where it may contain liquid water. They’re optimistic that the bright light emitting from the star could possibly help them to study the atmospheres on the planets.
“The host star Gliese 887 is the best star in close proximity to the sun to understand whether its exoplanets have atmospheres and whether they have life, because it is such a bright and quiet star,” Jeffers noted. As for their next project, “our next step is to see if there is a third planet, and to try and detect exoplanetary atmospheres using the James Webb Space Telescope due to be launched next year,” Jeffers said.