The hits, they just keep coming!
News was made in February when astronomers found seven potential earth-like planets orbiting the red dwarf star Trappist-1.
Wednesday, another red dwarf star is making headlines with the announcement of a ‘super earth’ found orbiting around the small red star LHS 1140.
VOA spoke with Jason Dittmann, from the Harvard-Smithsonian Center for Astrophysics, about the find.
He is the lead author of the paper laying out the new findings, which is being published Thursday in the journal Nature.
He calls the planet a “Super Earth,” not because it’s any better than our blue-green sphere, but because it “is somewhere between the size of the Earth (the largest rocky planet in the Solar System) and Neptune. These planets are actually pretty common, but we don’t have any of them in our own Solar System so we don’t know much about them.”
Finding one is a big deal in general. But this one, dubbed LHS 1140b, is extra-special because it has turned up in the dwarf star’s habitable zone, that area in space where liquid water can exist on the surface.
The planet is 10 times closer to the star than Earth is to the sun, but red dwarfs are much smaller and much cooler than the giant inferno that keeps us warm.
The other special thing about this planet is that it’s about 5 billion years old, and according to Dittmann, “Five billion years should be more than enough time for life to develop [if it’s easy to develop, no one knows!] So this is definitely a good thing.”
Too close for comfort
In general, one big problem with the habitable planets scientists have found around red dwarfs — and this goes for a few of the seven they’ve found on Trappist-1 — and Proxima b, another found last year — is that they are so close to their star that the stellar radiation that is bombarding the planets can literally strip away any atmosphere.
And this may be the case here.
But LHS 1140, according to team member Nicola Astudillo-Defru, “spins more slowly and emits less high-energy radiation than other similar low-mass stars.” That’s good news because the planet is so old and so big that chances are decent that it’s managed to hold onto an atmosphere.
Another bit of good news is that terrestrial planet LHS 1140b as seen from earth passes almost directly in front of its star, and that makes it a lot easier to do follow up research that Dittmann and his colleagues are already planning.
“We’re definitely already applying for as much telescope time as we can get our hands on,” Dittmann says, “to start looking at this planet’s atmosphere. And when the next generation of telescopes come online [The James Webb Space Telescope, and the ground-based Giant Magellan Telescope (GMT) and European-Extremely Large Telescope (EELT) ], we’ll be in a great spot to find out what sorts of atmospheres planets around M dwarfs have.”
The Webb telescope is expected to launch next year, but the Giant Magellan telescope won’t be online until 2025, and the EELT won’t be working until 2024.
That’s a long time to wait, and undoubtedly there’ll be a long list of planets to explore by then. But the hope is that by studying the atmosphere of all these planets in the habitable zone, we might find some of the biological signatures of living things. Two of the European members of the team, Xavier Delfosse and Xavier Bonfils say that it’s the best candidate so far.
“The LHS 1140 system might prove to be an even more important target for the future characterization of planets in the habitable zone than Proxima b or TRAPPIST-1. This has been a remarkable year for exoplanet discoveries!” wrote Delfosse and Bonfils.
And there certainly will be more on the way.