A set of super-Earths has been found orbiting one of our closest stars, scientists say.
Planets may be among the best opportunities to find life outside our solar system, say the researchers who discovered them.
The system orbits the star Gliese 887, the brightest red dwarf in the sky. That star is about 11 light years away.
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Super-Earths like newly found planets have a higher mass than Earth but are much smaller than the ice giants of our solar system, Uranus and Neptune. They are a key objective in the search for life on other worlds.
Also, the newly found planets are close to the habitable zone, where it is not too hot or cold for water to exist in liquid form, and could be rocky planets.
The star was discovered using the HARPS spectrograph, based at the European Southern Observatory in Chile, by RedDots astronomers looking for planets around red dwarfs.
They were able to infer the planets around the star using a technique called “Doppler wobble,” which allows them to observe the small movements of the star caused by the gravitational pull of the planets around it.
They discovered that the star appeared to be orbited by planets that have orbits that would give them years of just 9.3 and 21.8 days on Earth. That suggests that the planets move very fast around their star, even faster than Mercury.
Gliese 887 is also dimmer and smaller than our Sun, meaning that planets could get much closer to the star while remaining potentially habitable.
Astronomers also discovered that the red dwarf is less active than our Sun. If it were as active as our star, Gliese 887 would probably blow up the atmospheres of the planets around it, but its relative calm means that the world could still have its atmospheres, an indication that they could support any life there.
Also, the brightness stays fairly constant over time. That means it should be easier to detect atmospheres in the system using technology like the James Webb Space Telescope, which has the ability to “smell” the composition of an atmosphere at a distance.
That has been touted as the successor to the Hubble Space Telescope, but has been subject to several delays. Astronomers hope to use it and other equipment to investigate the newly discovered worlds, looking at them from a relatively close distance.
“These planets will provide the best possibilities for more detailed studies, including searching for life outside our Solar System,” said Sandra Jeffers of the University of Göttingen and lead author of the study.
The new research is published in an article titled ‘A System of Multiple Super-Earth Planets Orbiting the Brightest Red Dwarf Star GJ887,’ in the journal Science today.