"Super Earth" has been found orbiting a single star closest to our Sun, scientists said on Wednesday in a breakthrough that could illuminate the planet's closest neighbor Earth.
Astronomers study Barnard's Star, a red dwarf for only six light years – practically in our backyard, galactic speaking – and seeing the "frozen, dim world" at least 3.2 times heavier than Earth.
The planet, now known as Barnard 's Star b, is the closest to Earth in the outer solar system and orbits its parent star once every 233 days.
"This is important because this is really our next neighbor and we want to meet our neighbors in general," Ignasi Ribas, from the Catalonia Institute for Space Studies and the Spanish Space Science Institute, told AFP.
Even though it is relatively close to its parent star, the planet receives less than two percent of the energy that Earth gets from the Sun, and the team estimates it has a surface temperature of -170 ° C – too cold to support life as we know it.
"This is clearly not in the habitable zone, there is no liquid water. If you have water or gas it might be in solid form so that is why we call it frozen," Ribas said.
Darkness of a Red Dwarf
In human efforts to map planets in the night sky, most historic research has focused on brighter new stars, which produce more light and increase the chances of scientists realizing whatever is orbiting them.
However, because the Barnard Star is a red dwarf star, a small and cooled star that may be about two times older than the Sun, it produces relatively little light so it is difficult to distinguish every object in its orbit.
To find Barnard's Star, Ribas and the team studied more than 20 years of observation of seven separate instruments.
They then used a phenomenon known as the Doppler effect to track the impact of its gravitational pull on its parent star.
Astronomers can use this technique to measure the speed of the planet and, therefore, mass.
"We have all worked hard for this breakthrough," said Guillem Anglada Escude, of Queen Mary University in London, who co-authored the study, published in the journal Nature.
& # 39; Mini-Neptune & # 39 ;?
The team works with the European Southern Observatory using astronomical instruments so that they can accurately detect changes in the speed of stars as small as 3.5km / h – the speed of walking gently.
It is estimated that Star Barnard tore space around 500,000 km / h, making it the fastest moving object in the universe.
Ribas said that although star observers can predict their size and orbit with relative accuracy using the Doppler effect, any attempt at this stage to find out what looks like a new planet will be a "guess".
"It's kind of in the fuzzy region with respect to its properties. We have seen these mass planets rocky, which means that it can look like an Earth with a solid surface with the potential for some atmosphere or some frozen layers above," he said. .
"Or maybe that's what we call mini-Neptune, like a small version of the giant gas of our solar system."
It may be cold, unfriendly and all but not visible but the new planet has one thing that happens for it: it's really close.
The only extrasolar planet known close to Earth was discovered in 2016 which orbits one of the stars in the Alpha Centauri system, only more than four light years away.
"There are not many stars in our immediate neighborhood. Invest to find it expensive," Ribas said.
"This is really close and therefore if you have hope – like me – in the end seeing these planets to study it in detail, we have to start with the direct ones. That could potentially lead to other discoveries."
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