And Professor John Barnes, a research fellow with the Open University, has said the fact that seven planets have now been confirmed orbiting stars close to the Earth’s solar system suggests they are commonplace – albeit not all habitable. The system of super-Earth planets – which are possibly rocky worlds, but larger than Earth – was spotted orbiting the nearby star Gliese 887, with the results published in the scientific journal Science yesterday. Prof Barnes told Express.co.uk: “One of the most exciting things about this system is that the host star is very bright.
“It is the brightest red dwarf star in the solar neighbourhood.”
Therefore, even though Gliese 887 is 2.5 times further away than Proxima Centauri and its planet, it appears more than 30 times brighter when viewed from Earth.
Prof Barnes added: “We detect the planets using light from the star that they orbit, so the more light we have, the easier it is to learn more about the planets once we have detected them.
“As such, GJ887’s planets are particularly exciting objects for further follow-up observations aimed at searching for the presence of atmospheres.”
Red dwarf stars such as Gliese 887 and Proxima Centauri were ubiquitous, Prof Barnes said.
He added: “Although they’re smaller and dimmer than our own Sun (roughly half the size or smaller), they are the most numerous type of star in the solar neighbourhood.
“Three-quarters of all stars near the Sun are red dwarfs, so we cannot ignore them for sure.
“And the fact that we are finding systems with one or more planet orbiting many of these stars is enormously exciting.”
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“We do however know that life exists in very harsh and unexpected environments on Earth.
“Red dwarfs such as GJ 887 also pose challenges because for planets to be in their habitable zone, they most orbit much closer.
“The planet GJ 887c for instance is over eight times closer to its star than the Earth is to the Sun.
“Apart from being very hot, stars are usually not completely benign objects as they produce lots of high energy particles and radiation.
“This is not good for life. For example, we know UV radiation isn’t good for microbes and indeed for humans.
“However, we do know that GJ 887 is a particularly quiet star, which means it may be less of a threat to the development of life than many other similar stars.
Earlier this month, scientists revealed new estimates for the so-called Drake Equation aimed at calculating the number of civilisations in the galaxy, putting the number at anywhere between four and 211, with 36 being most likely.
Emphasising the daunting distances involved, Prof Barnes: “Those new estimates pointed out that the nearest planet would be 17,000 light years away.
“Two way communication would thus require thousands of years.”
However, he added: “In contrast, the stars that our project, Red Dots, is discovering are 4.2 light years (Proxima Centauri) or 10.6 light years (GJ 887), so they are a much more immediate and exciting place to start our search, even if they do not harbour intelligent life.
“We weren’t surprised when estimates of the actual number of planets, based on existing planets we had already discovered, started to tell us that planets are indeed ubiquitous.
“Estimates for red dwarf stars like GJ 887 for instance are telling us that there may well be more than one planet per star.
“Our Pale Red Dot project that announced the discovery of Proxima Centauri in 2016 and now the subsequent Red Dots project has now announced seven planets around four of the nearest stars to Earth.
“That’s an average of 1.75 planets per star! I must again stress though that not all of these planets are in the habitable zone.
“It is however fantastic to see that the Red Dots project is confirming recent estimates with real planets – and right on our doorstep!”