Scientists discover new Earth-sized 'pi planet' that orbits its star in 3.14 days

pi Earth (Source MIT)

Scientists at Massachusetts Institute of Technology (MIT), along with others, have discovered an Earth-sized planet, pi Earth, that rotates around its star every 3.14 days. The researchers had discovered signals of the planet in 2017 after evaluating data collected by the NASA Kepler Space Telescope’s K2 mission.

"By zeroing in on the system with SPECULOOS, a network of ground-based telescopes, the team confirmed that the signals were of a planet orbiting its star," MIT said on September 21.

The new planet is labelled K2-315b; it’s the 315th planetary system discovered within K2 data. The researchers estimate that K2-315b has a radius of 0.95 that of Earth’s, making it just about Earth-sized.

It orbits a cool, low-mass star that is about one-fifth the size of the sun. The planet circles its star every 3.14 days, at a blistering 81 kilometres per second, or about 1,81,000 miles per hour.

According to Prajwal Niraula, an MIT student, “The planet moves like clockwork.” Niraula is also the lead author of the paper titled 'π Earth: a 3.14-day Earth-sized Planet from K2’s Kitchen Served Warm by the SPECULOOS Team'.

While its mass is yet to be determined, scientists suspect that K2-315b is terrestrial, like the Earth. But the pi planet is likely to be inhabitable, as its tight orbit brings the planet close enough to its star to heat its surface up to 350 degrees Fahrenheit.

"This would be too hot to be habitable in the common understanding of the phrase,” says Niraula.

“We now know we can mine and extract planets from archival data, and hopefully there will be no planets left behind, especially these really important ones that have a high impact," says de Wit, an assistant professor in EAPS, and a member of MIT’s Kavli Institute for Astrophysics and Space Research.

Niraula and de Wit’s MIT co-authors include Benjamin Rackham and Artem Burdanov, along with a team of international collaborators.

The researchers are members of SPECULOOS, an acronym for the Search for Habitable Planets EClipsing ULtra-cOOl Stars.

Most recently, the network added a fifth telescope, which is the first to be located in the northern hemisphere, named Artemis — a project that was spearheaded by researchers at MIT.

The SPECULOOS telescopes are designed to search for Earth-like planets around nearby, ultracool dwarfs — small, dim stars that offer astronomers a better chance of spotting an orbiting planet and characterising its atmosphere, as these stars lack the glare of much larger, brighter stars.