HUBBLE REVEALS PLANETS WITH SIGNS OF SURFACE WATER IN TRAPPIST-1 SOLAR SYSTEM
Three planets discovered last year could have liquid water – the key to life as we know it – sloshing around on their surfaces. The planets sit in the ‘Goldilocks zone’ of TRAPPIST-1, an ultra-cool dwarf star located 40 light-years from Earth in the constellation of Aquarius.
In total, four planets in the TRAPPIST-1 system orbit within this habitable zone, where the temperature’s just right for liquid water, and life, to exist. Astronomers searched all four planets for a hydrogen-rich and cloud-free atmosphere, which would indicate that the planets are likely to be gaseous, like Neptune. This type of atmosphere was only found on one of the four planets. The other three lacked hydrogen in their atmosphere, meaning they could hold surface water, just like Earth.
“This discovery is an important step towards determining if the planets might harbour liquid water on their surfaces, which could enable them to support living organisms,” said lead researcher Julien de Wit, from the
Massachusetts Institute of Technology.
The researchers used the Hubble Space Telescope to measure light emitted from the star TRAPPIST-1 as it passed through each of the planets’ atmospheres. As light interacts with atoms and molecules in the planets’ atmospheres, slight changes occur in its distribution of frequencies, or spectrum. By studying these changes, the researchers were able to determine some of the chemicals present in the TRAPPIST planets’ atmospheres.
A few different possibilities exist as to what kind of atmospheres these planets might have, but more powerful telescopes are needed to help us understand more.
“The next generation of telescopes – including the James Webb Space Telescope – will allow us to probe deeper into their atmospheres,” said lead author Prof Michael Gillon, from the University of Líege,
Belgium. “This will allow us to search for heavier gases such as carbon, methane, water, and oxygen, which could offer biosignatures for life.”
Artist’s impression of the TRAPPIST-1 dwarf star, as viewed from one of its planets