"Using numerical simulations to identify planets stable for millions of years, a team of researchers concluded that six of the seven roughly Earth-sized planets in the TRAPPIST-1 planetary system are consistent with an Earth-like composition. The exception is TRAPPIST-1f, which has a mass of 25% water.
This artist's impression displays TRAPPIST-1 and its planets reflected in a surface. Image credit: NASA / R. Hurt / T. Pyle.
TRAPPIST-1 is an ultracool dwarf star in the constellation Aquarius, 38.8 light-years away.
The star is host to a remarkable planetary system consisting of seven transiting planets: TRAPPIST-1b, c, d, e, f, g and h.
All these planets are similar in size to Earth and Venus, or slightly smaller, and have very short orbital periods.
"The goal of exoplanetary astronomy is to find planets that are similar to Earth in composition and potentially habitable," said Dr. Billy Quarles, a postdoctoral researcher at the University of Oklahoma and lead author of a paper reporting the results in the Astrophysical Journal Letters…"