With every new exoplanet discovery, we seem to get that much closer to finding evidence of extraterrestrial life. A new exoplanet identified in orbit of a nearby star could be the best place to look yet. Astronomers have confirmed a star 39 light-years away plays host to a planet that is much more Earth-like than any we’ve been able to spot in the past. The planet, known as LHS 1140b, is larger than Earth, but it’s rocky and could well have liquid water on its surface.
According to a new publication in Nature, the international team of astronomers with the Mearth project used an array of eight telescopes at Cerro Tololo Inter-American Observatory in Chile to find LHS 1140b. Luckily, this planet passes in front of its parent star frequently — like many other planets we’ve spotted, it orbits close to a small, cool star. This allowed the team to characterize it to a degree not possible with other discoveries. For example, the mass of all those planets orbiting Trappist-1 are mere estimates, and we know very little about the composition of the exoplanet in orbit of Proxima Centauri.
What we know about LHS 1140b is that it’s about 40 percent larger than Earth with 6.6 times the mass. Thus, gravity on LHS 1140b would be three times greater than Earth’s. So if you weigh 175 pounds here, you’d tip the scales at 525 pounds. It would be more accurate to call this a Super-Earth, 32 of which have been discovered in recent years. LHS 1140b might not be a pleasant place for humans to hang out, but it’s well within the range of a rocky planet, not a gas giant like Jupiter or Neptune. Scientists also expect LHS 1140b could have liquid water on its surface simply based on its distance from the star.
The Mearth array used to find LHS 1140b.
A trip of 39 light-years isn’t something humanity is capable of right now, but that’s still in our galactic neighborhood. Because it transits its star so frequently, there is hope scientists will be able to measure LHS 1140b’s atmosphere. If we find both oxygen and carbon, that could mean something is alive out there. Astronomers are already placing LHS 1140b at the top of their lists when new telescopes like the James Webb Space Telescope come online. This instrument will launch in October 2018, allowing astronomers to get a closer look at a variety of objects, including exoplanets like LHS 1140b. There are also some ground-based telescope projects that could allow for closer examination of LHS 1140b.