Harvard expert discovers LHS 1140b, a “habitable” exoplanet


Scientists from the Harvard-Smithsonian Center for Astrophysics discovered a new exoplanet named LHS 1140b. This ‘super-Earth’ orbits a red dwarf just 39 light years away from us, and it is believed to have the right conditions to host life.

The research team made the discovery last year, but it was only this Wednesday when their findings were officially published in the journal Nature. Jason Dittmann was the lead author, and he worked with more than 20 peers from different institutions.

LHS 1140b is the latest exoplanet championed as a potential haven for alien life outside our Solar System. In February, astronomers announced the discovery of four more promising planets orbiting the TRAPPIST-1 system.

Jason A. Dittmann photo.
Image: Harvard.

How did scientists discover LHS 1140b?

Astronomers first detected faint signals of the exoplanet’s existence in 2014, but disregarded it as an anomaly and paid no particular attention to it. Jason Dittmann unearthed the data a year later and started researching on his own.

The young scientist used a technique known as the transit method to confirm his suspicions. This method consists of observing carefully the light of a star in search for subtle brightness dips that could be planets obstructing it as they orbit (transit) around it.

After having probable cause to believe there was an exoplanet out there, Dittman enlisted a team of researchers to help him out with observations at the MEarth South facilities in Chile.

The MEarth Project is an initiative that specializes in studying M-dwarf stars like LHS 1140, the red dwarf that LHS 1140b orbits. Further studies were carried out using the European Southern Observatory’s (ESO) High Accuracy Radial Velocity and Planet Searcher (HARPS).

At one point early on, Dittmann also called an amateur astronomer in Australia for help. TG Tan was able to confirm the sightings from his backyard observatory in Perth, taking his list of discovered exoplanets to 26.

LHS 1140b may have liquid water and an atmosphere

Scientists say that LHS 1140b is particularly promising for several reasons. The primary one is that the exoplanet sits right in the habitable zone of its system, 12 parsecs away from its M-dwarf star.

The super-Earth is located in the Cetus constellation of the Messier 77 spiral galaxy. We would need to travel 39 light years to get there, which in cosmic distances isn’t that far away.

LHS 1140b is 1.4 times the size of the Earth, but it is almost seven times as dense. This fact has led scientists to believe the planet has a rocky composition with a core made of a heavy element, possibly iron.

By studying its orbit and trajectory under the transit method, researchers were also able to tell the planet has had a relatively uneventful existence. They estimate it is five billion years old, and that its calm life has led to the development of some sort of water or ice formation on its surface.

Dittmann and others don’t discard the possibility of finding life in LHS 1140b, but there are some obstacles they need to consider. Its proximity to the red dwarf poses a very real threat of dangerous radiation levels that could have left the planet barren and looking somewhat like Venus.

Still, they remain hopeful to find more about this promising prospect. The team has already arranged observation time using the Hubble Space Telescope in the coming months. They are also eager to use instruments like the James Webb Space Telescope launching next year and the Giant Magellan Telescope in the 2020s.

Source: Nature