Two Newly Discovered Super-Earths Are Orbiting A Star Just 11 Light Years Away

An international team of astronomers has detected super-Earths orbiting a nearby star just 11 lightyears away. The discovery of Gliese 887's super-Earths opens up excellent opportunities for future studies of such planets in the search for extraterrestrial life.

Gliese 887 is one of the closest stars to our Sun and is the brightest red dwarf in the sky. Using a technique called the "Doppler wobble," in which astronomers detect possible planets around a star by measuring the back and forth wobbles caused by the gravitational pull of a planet, the researchers of a new study detected two planets orbiting Gliese 887: Gliese 887b and Gliese 887c.

Gliese 887b and Gliese 887c are considered super-Earths because they are larger than the Earth but still smaller than the ice giants Uranus and Jupiter. Both of them are close to the habitable zone of the system, which is actually closer to the star compared to the zone where the Earth is because Gliese 887 is smaller and dimmer than the Sun.

"The planets are interior to, but close to the inner edge of, the liquid-water habitable zone," the researchers wrote in their study published in the journal Science.

Based on the signals, both super-Earths are moving much faster than Mercury, which completes an orbit around the Sun in 88 Earth days. Specifically, Gliesse 887b orbits its host star in just 9.3 Earth days while Gliese 887c completes an orbit in 21.8 Earth days.

Interestingly, the researchers also found another signal that could have come from another planet in the same system. This third possible super-Earth is farther from the star than the other two, and takes 50 days to complete an orbit.

Apart from discovering the nearby super-Earths, the researchers also found that Gliese 887 has very few sunspots, which means that it is not as active as the Sun and would therefore not sweep away the super-Earths' atmospheres. As such, it is possible that these planets have thicker atmospheres than the Earth, allowing them to potentially host life.

Still, the two super-Earths are likely too hot to host life, with the researchers estimating Gliese 887c's temperature to be around 70 degrees Celsius. The third potential planet, on the other hand, might be in the habitable zone and therefore could have more favorable conditions for potential life.

Another thing that the researchers found is that Gliese 887's brightness is quite constant, which would make future studies of the super-Earths' atmospheres much easier.

Together with the fact that Gliese 887 is quite close to our Sun, this system provides an excellent opportunity for more studies, especially with the James Webb Telescope set to be launched in 2021.

"These planets will provide the best possibilities for more detailed studies, including the search for life outside our Solar System," study lead author Dr. Sandra Jeffers said in a press release from the of the University of Göttingen.