SAN FRANCISCO (Diya TV) — Astronomers from NASA and the European Southern Observatory announced Wednesday the discovery of four new Earth-sized exoplanets orbiting a star about 40 light-years away, and that three may contain liquid water and be able to sustain life.

The star’s small grouping of planets now boasts the most Earth-sized worlds of any system astronomers have ever discovered, as well as the most exoplanets that may be able to support surface life.

A team of Belgian astronomers were able to make the discovery using space- and ground-based telescopes as each exoplanet passed in front of its host, a red dwarf star known as TRAPPIST-1. These orbits created dips in the Jupiter-sized star’s light output that helped astronomers determine the sizes, compositions, and orbits of each of the celestial bodies.

The four exoplanets join three others circling TRAPPIST-1 that were discovered by the same team early in 2016, after which the group said it intensified follow-up efforts.

“This is an amazing planetary system, not only because we have found so many planets, but because they are all surprisingly similar in size to Earth,” said Michaël Gillon, astronomer from the University of Liège in Belgium and lead author of the paper about the discovery published in the journal Nature.

All seven planets that surround the star — which has only about eight percent the mass of our sun — orbit more tightly to their host than any of the planets in our system are to the sun. TRAPPIST-1 doesn’t emit much energy, but the inner six exoplanets are in such tight orbit around their host that they have temperatures comparable to those on Venus, Earth, and Mars.

The observations and measurements taken by astronomers suggest the inner six planets have rocky compositions, and that three of TRAPPIST-1’s surrounding bodies may orbit within a habitable zone that represents the “holy grail for planet-hunting” as they could be warm enough to host surface water and oceans.