admin Three new planets, which orbit a star situated 73 light years away from Earth, have been found. The trio are among the smallest and nearest exoplanets known to date.
Within the system known as TOI-270 there is a rocky planet that is slightly larger than Earth, as well as two gaseous planets roughly twice Earth’s size. While the temperature range at the very top of the furthest planet could support some forms of life, the atmosphere itself is probably too thick and dense, creating an intense greenhouse effect making it an unlikely host for water and life.
Maximilian Gunther at the Massachusetts Institute of Technology and his colleagues made the discovery using NASA’s Transiting Exoplanet Survey Satellite (TESS), which was sent into space in 2018 with the aim of finding new worlds around neighbouring stars that could support life.
“TOI-270 will soon allow us to study this ‘missing link’ between rocky Earth-like planets and gas-dominant mini-Neptunes, because here all of these types formed in the same system,” says Gunther.
Here we have small rocky planets such as Earth, Mercury, Venus, and Mars or much larger gas-dominated planets like Saturn, Jupiter, Uranus, and Neptune, but nothing in the middle.
The closest of the three planets, TOI-270 b, takes little over three days to orbit its star, with TOI-270 c taking 5.7 days, and TOI-270 d at 11.4 days.
TESS was launched on April 18 last year and is designed to observe almost the entire sky. The satellite looks for dips in light that might betray the presence of a planet passing or transiting in front of its host star.
In April, it found its first Earth-sized planet, which orbits a star 52 light years away – though temperatures of more than 400C rule out any prospect of finding life on the planet. “TOI-270 is a true Disneyland for exoplanet science, and one of the prime systems TESS was set out to discover,” Gunther says. “It is an exceptional laboratory for not one, but many reasons – it really ticks all the boxes.”
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