First Hints Of "Substantial" Water Found In TRAPPIST-1 System

Battle stations people, this could be the real deal. NASA’s Hubble telescope has found evidence that the planets in the TRAPPIST-1 system could support large amounts of water.

If that hasn’t piqued your interest, it should do. There are seven Earth-sized planets in the TRAPPIST-1 system, 40 light-years away, at least three of which are in the host red dwarf star’s habitable zone.

This study suggests that the outer planets in the system, including those in the habitable zone, could harbor “substantial” amounts of water. If confirmed, this could have pretty major implications in the search for life.

“[T]he outer planets of the TRAPPIST-1 system might thus still harbor substantial amounts of water,” the team led by the University of Geneva write in their paper, which is available online.

The researchers came to this possibility after studying ultraviolet radiation from the planets as seen by Hubble. Ultraviolet sunlight can break apart molecules in the atmosphere of a planet, including water vapor, which can produce hydrogen and oxygen.

This hydrogen gas appears to have escaped some of the atmospheres of the TRAPPIST-1 planets, which Hubble was able to detect. This is a possible indicator that there is water vapor in the atmospheres of these planets.

Importantly, the study looked at how much water the planets may have lost, not how much they still had. For the innermost planets, they suggest they could have lost 20 Earth oceans-worth of water over the last 8 billion years.

The outer planets, however, may have lost just three Earth oceans-worth, suggesting they may still have water today.

Artist's impression of TRAPPIST-1f. NASA/JPL-Caltech

“Our results indicate that atmospheric escape may play an important role in the evolution of these planets,” said co-author Julien de Wit, from the Massachusetts Institute of Technology, in a statement.

Now, of course, we can’t jump to any conclusions about these planets just yet. We don’t know for certain if they do have water, and we certainly don’t know if they could harbor life. But this study is the latest to paint an interesting picture of this system, which contains the largest number of Earth-sized worlds we’ve found in any system.

As is always the case, the launch of the James Webb Space Telescope in October 2018 will open up new avenues of study for planets like this. Until then, we can get a few tantalizing hints at what might be awaiting us out there.