spaceSpace and Physics

We Might Be Able To Find Vegetation In The TRAPPIST-1 System


Jonathan O'Callaghan

Senior Staff Writer


Is one or more of these planets habitable? NASA/JPL-Caltech

A new study is trying to work out if there might be vegetation in the TRAPPIST-1 system, and how we would go about finding it.

Led by Tommaso Alberti from the University of Calabria in Italy, the team looked at how much land and water might be expected on each planet, and from that deduced that any vegetation should notably change the appearance of each world.


The research is available on arXiv, and will be published in The Astrophysical Journal.

TRAPPIST-1 shot to stardom earlier this year, when it was discovered there were seven rocky planets in orbit around this red dwarf star 40 light-years away – the most rocky planets we had found in one system. At least three of these appeared to be in the habitable zone of the star, where conditions could be just right for liquid water – and maybe life – to exist.

In this study, researchers used a “simply climate-vegetation energy-balance model” to study the climate of each planet. TRAPPIST-1d was found to be the most stable world for Earth-like conditions, residing in a position that was most suited to liquid water. That’s interesting, because previously e, f, and g looked best.

While we can’t directly look at the planets, we can look at the star’s light coming through their atmosphere. In the future, we may also be able to see light reflected on their surfaces, which could be vital in trying to work out if they are habitable.


In this latest study, the researchers said that the outgoing radiation from each planet might be dependent on the vegetation and also on the atmospheric composition, so further studies of the planets could reveal some of their surface features.

We don't yet know what the planets look like. NASA/JPL-Caltech

Once the greenhouse effect of an atmosphere is properly accounted for, the team said that future telescopes could confirm the presence of both continents and vegetation on the TRAPPIST-1 worlds, or indeed other planets.

“We are able to investigate different scenarios for TRAPPIST planetary system moving from rocky planets to Earth-like planets with similar and/or different greenhouse conditions and to underline the role of vegetation in defining a particular climate state,” Alberti told Seeker.

This idea has been mooted before. Back in February this year, scientists proposed that the type of light reflected could be dependent on any vegetation that’s present. Interestingly, as this star emits light mostly in infrared, it’s thought that any vegetation on these planets would be darker to soak up more energy.


“If we were to land on one of the planets, don’t expect to see an oasis or green plants,” Lisa Kaltenegger, director of the Carl Sagan Institute in New York, told IFLScience back then. “You would actually expect plants that basically use all of the light and don’t reflect any. So very dark vegetation that can take up any light it gets, any energy.”

(H/T: Seeker)


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