The trio are among the smallest and nearest exoplanets known to date. They were discovered using Nasa’s Transiting Exoplanet Survey Satellite (TESS), which was sent into space last year with the aim of finding new worlds around neighbouring stars that could support life.
Within the system known as TOI-270, there is a rocky super-Earth that is slightly larger than our own planet, as well as two gaseous sub-Neptunes, roughly twice Earth’s size.
While it is believed the temperature range at the very top of the furthest planet could support some forms of life, the atmosphere itself is thought to be too thick and dense, creating a greenhouse effect.
However, scientists think there is a good chance of more planets beyond TOI-270 d – the furthest of the three.
The discovery, published in Nature Astronomy, also has researchers curious about a type of “missing link” planet that does not exist in our own solar system. 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.