A group of astronomers has discovered a system of super-Earth planets that are orbiting a nearby star called Gliese 887. That star is the brightest red dwarf in the sky. A super-Earth planet is one that has a mass higher than that of the Earth, but substantially lower those than the ice giant planets in our solar system, Uranus and Neptune.
Researchers say that the newly discovered super-Earth planets lie close to the red dwarf’s habitable zone where water could exist in liquid form. The team also believes that the planets could be rocky worlds similar to the Earth. The team has been monitoring Gliese 887 using the HARPS spectrograph at the European Southern Observatory in Chile.
The team used a technique known as “Doppler wobble” that measures the tiny back-and-forth wobbles of the star caused by the gravitational pull of planets. The regular signals the team recorded correspond orbits of 9.3 and 21.8 days, indicating a pair of Super-Earth planets orbiting the star. The planets were labeled Gliese 887b and 887c.
The team has estimated that the temperature of Gliese 887c is around 70-degrees Celsius. Gliese 887 is one of the closest stars to our Sun at approximately 11 light-years away. However, it’s about half the size of our Sun, meaning its habitable zone is much closer to the star that it is in our solar system. The researchers also discovered a pair of interesting facts about Gliese 887.
One is that the star has very few starspots, unlike our Sun. If it had more starspot activity, it would produce a strong stellar wind and that outflowing of material could erode the nearby planets’ atmospheres. That means that the new exoplanets could retain their atmospheres or have thicker atmospheres than Earth with the possibility of hosting life. The team also found that the brightness of Gliese 887 is almost constant making a prime candidate for study by the James Webb Space Telescope.