- Seven planets recently spotted orbiting a dim star in our Milky Way galaxy are rocky, seem to have water, and are potentially “habitable”, researchers studying the distant system said Monday.
- Though much remains unknown about the planets’ surfaces and atmospheres, the new measurements have not ruled out the possibility that they may harbour even rudimentary life, the scientists reported.
About the findings:
- Research teams gleaned more information about the dwarf star at the centre of the Trappist-1 system, as well as improved measurements of the size and mass of each planet, and the composition of their atmospheres.
- All seven are mostly made of rock, with up to 5% of their mass in water — though it may be in the form of gas or ice, or trapped deep inside the rocky orbs.
- A year ago, researchers announced the discovery of the seven Earth-like planets orbiting Trappist-1, an “ultracool” red dwarf star some 39 light years from our home.
- “But they have suitable characteristics and are to date the best place beyond the edge of our (Solar) system to search.”
- The presence of liquid water is considered essential for life to exist anywhere.
- Astronomers used the Hubble Space Telescope to learn more about the Trappist system by studying the planets’ atmospheres as they passed in front of their star, appearing as a dark, travelling dot from the observer’s point of view.
Cooler than the Sun:
- All seven planets were considered potential candidates for harbouring water, but the chances to find it in liquid form are highest in the temperate “Goldilocks” zone — not too far from the star for it to be frozen, nor too close to evaporate.
- The Trappist-1 system is considered the current best hope for finding evidence of alien life.
- Compared to our Solar System, the Trappist-1 family is very tightly-knit. With orbits ranging from 1.5 to 12 days, the planets would have fit comfortably in the distance between the Sun and its closest planet, Mercury.
- Trappist-1 has a mass less than 10% the mass of our Sun and is much cooler, which explains why its planets can orbit so nearby.