Rock and water for Trappist-1 exoplanets

The Trappist-1 planets discovered last year are rocky and could be rich in water, according to researchers' findings, particularly those of the Laboratory of Astrophysics of Bordeaux. This research has now been published in two international journals, Nature Astronomy and Astronomy & Astrophysics.

  • 20/03/2018

Vue d'artiste du système Trappist-1 © ESO/M. Kornmesser Vue d'artiste du système Trappist-1 © ESO/M. Kornmesser

Two scientific publications revisit the seven planets discovered last year that orbit the dwarf star Trappist-1. These new studies reveal that these seven planets are mostly made up of rock and that they do not have a hydrogen-rich atmosphere, unlike planets such as Uranus and Neptune. Their densities suggest that some of them could include up to 5% of water mass in their composition (whereas water only represents 0.1% of the Earth's mass). In terms of size, density and incoming radiation levels from its star, the fourth planet is the most similar to Earth. This planet would appear to be the rockiest of all the planets, even though the presence of water has not been ruled out.

These studies were conducted by an international team involving the researchers Anthony Caldas, Jérémy Leconte, Sean Raymond and Franck Selsis of the Laboratory of Astrophysics of Bordeaux (LAB, CNRS unit and the University of Bordeaux), as well as researchers from the CEA astrophysics department and Laboratoire de météorologie dynamique (CNRS /École Polytechnique/Sorbonne University/ENS Paris). They were published on February 5, 2018 in Nature Astronomy and Astronomy & Astrophysics.


Astrophysicist - CNRS Researcher

Astrophysicist - CNRS Researcher

Astrophysicist - CNRS Researcher

Astrophysicist - University of Bordeaux PhD student