Astronomers have taken a significant step toward finding a habitable Earth-like planet beyond our Solar System with the detection of an atmosphere on LHS 1140 b, a rocky exoplanet orbiting a dim star about 49 light-years away.

Traces of helium were detected in the planet's atmosphere, marking the first time such a discovery has been made on a rocky, Earth-like planet at Earth-like temperatures. LHS 1140 b is slightly larger than Earth and has five times its mass. It also lies within its star's Goldilocks zone, where temperatures are suitable to support liquid water on the surface.

"This [planet] is the best place currently to look for life outside of our Solar System, because it has all the main ingredients that we think are essential for life," said Collin Cherubim, who led the study while at Harvard University. He added, "I hope this is just the first [discovery] of many to come."

Modeling published in the journal Science suggests LHS 1140 b could be a water world, with a mostly Earth-like rocky composition plus about 10 percent water by mass, according to Dr. Evans-Soma. The atmosphere is thought to be vital for life as it stabilizes the climate, protects the planet from radiation, and traps water.

The host star is old and quiet, never observed to flare, which is favorable for habitability. Although the helium signal was detected only once and not in a subsequent observation, this is not unusual for helium detection.

Dr. Evans-Soma also noted that telescope time has been awarded to observe a planet similar to LHS 1140 b, potentially expanding the search for habitable worlds.

Sources

ABC Australia News