Two Super-Earths Discovered Just 11 Light-Years Away From Our Planet
Astronomers have discovered two super-Earths in a star system just 11 light-years away from our planet.
Both planets are reportedly ‘just within the habitable zone’ of Gliese 887 – around half the size of the sun and dubbed ‘one of the brightest red dwarfs in the sky’ – where water is able to exist in its liquid form and rocky worlds may be found, although there’s a chance they may be too warm to sustain much life.
As for what a super-Earth is, the University of Göttingen explained they have a ‘mass higher than the Earth’s but substantially below those of our local ice giants, Uranus and Neptune’. With this recent discovery, researchers are hoping to decipher the planets’ atmospheres.
The university led a team from all across the world – including the likes of the University of Hertfordshire, Open University and Queen Mary University of London – on the RedDots project. Using the High Accuracy Radial velocity Planet Searcher, known as the HARPS spectrograph, at the European Southern Observatory in Chile, they found Gliese 887b and Gliese 887c.
Dr Sandra Jeffers, lead author of the study published in the journal Science, said in the university press release: ‘These planets will provide the best possibilities for more detailed studies, including the search for life outside our Solar System.’
Researchers were able to find the super-Earths via the ‘Doppler wobble’ technique, allowing them to ‘measure the tiny back and forth wobbles of the star caused by the gravitational pull of the planets’. These signals indicated orbits of 9.3 and 21.8 days, signalling the presence of two planets bigger than our own, but moving rather quickly.
Gliese 887c is also estimated to have a temperature of around 70°C. In addition, the habitable zone of this system is much closer than Earth’s position in correspondence to the sun, meaning ‘brightness of Gliese 887 is almost constant’. If our sun was as active as Gliese 887, our atmosphere would likely be swept away by the stellar winds.
Dr John Barnes, an astrophysicist at the Open University and further author on the study, explained:
Close orbiting planets like these have a high chance of being tidally locked to their host star. This means that as the planet orbits its star, the same hemisphere always faces the star. For the planets orbiting GJ 887, half of the planets would be in perpetual daytime and the other half in perpetual night time. So, it could be much cooler on some parts of the planets than others.
Astronomers already have their heart set on using the James Webb Space Telescope – the successor to the Hubble Telescope – to learn more about the system. A third signal was also detected, although researchers are ‘cautious’ and ‘currently unavailable’ to confirm whether it’s a planet.
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