Here is Pi Earth, a new exoplanet with an orbit of 3.14 days

 Pi planet' alien world takes 3.14 days to orbit its star

It is a new rocky planet similar in size to Earth. Not only that: its name is due to the mathematical constant pi, since the planet orbits its star every 3.14 days

    
Rocky, as big as the Earth , but with a hot surface. It is the new exoplanet discovered by researchers from the Massachusetts Institute of Technology (MIT), just named Pi Earth (π Earth). The planet, in fact, revolves around its star every 3.14 days , a period that recalls the value of the famous pi (π), a mathematical constant that indicates the relationship between the perimeters of a circle and its diameter. To find out, the researchers used data collected in 2017 by Kepler's K2 mission , the space telescope of NASA and Speculoos(The Search for habitable Planets EClipsing ULtra-cOOl Stars), a network of four space telescopes located in the Atacama Desert, Chile. "The planet moves like a clock" , comments Prajwal Niraula , researcher at MIT and author of the study just published on the pages of the Astronomical Journal.

The new planet, labeled K2-315b , is the 315th planetary system discovered thanks to data from the K2 mission. From the analysis, the researchers estimate that Pi  Earth  has a radius very similar to that of our planet, orbiting a cold and small star, called Epic 249631677 , about one-fifth the size of the Sun , every 3.14 days, at the speed of 81 kilometers per second. Although its mass has yet to be calculated, researchers speculate that it is similar to Earth's, although Pi Earth is probably not habitable.: the orbit so close to its star, in fact, causes the planet's surface to reach very high temperatures, equal to about 180 degrees centigrade. “It would be too hot to be habitable,” comments Niraula, noting however that Pi Earth, besides being interesting for its association with the mathematical constant, is an excellent candidate for studying its atmosphere .

Speculoos telescopes , the researchers explain, are designed to search for Earth-like planets that orbit in the vicinity of ultra-cold dwarfs, small, faint stars that offer astronomers more opportunities to discover celestial bodies and characterize their atmosphere. "These ultra-cold dwarfs are scattered all over the sky," explains co-author Artem Burdanov . In particular, astronomers observe individual stars in search of transit signals or periodic drops in the brightness of a star, which could indicate a possible passage of a planet in front of the star.

For Pi Earth , the Kepler telescope observed a portion of the sky in 2017 that included the cold dwarf Epic 249631677 and analysis revealed about 20 decreases in its brightness, which repeated every 3.14 days. From subsequent observations, the researchers discovered that these signals were probably due to a transiting planet and to demonstrate this they pointed the telescopes of Speculoos in the direction of the star, finally managing to observe three transits of the planet distinctly. The planet and its atmosphere, the researchers say, could be studied by the James Webb Space Telescope (JWST). "There will be more interesting planets in the future, just in time for the JWST, a telescope designed to probe the atmosphere of these alien worlds , ” concludes Niraula. "We hope that one day we will be able to find smaller planets, even as small as Mars ."

The pi planet's surface is probably too hot to support life as we know it.

Scientists have found an alien world that orbits its host star every 3.14 Earth days, a close approximation of the famous mathematical constant pi, the ratio between a circle's circumference and its diameter. (Pi is an irrational number; the digits to the right of its decimal point go on forever.)

The exoplanet, called K2-315b, orbits a dwarf star that lies 186 light-years from Earth, a new study reports. K2-315b was spotted in data gathered in 2017, during the extended K2 mission of NASA's Kepler space telescope, and was confirmed using 2020 observations by a network of ground-based telescopes called SPECULOOS (a creative acronym for "Search for Habitable Planets Eclipsing Utra-cool Stars").



"The planet moves like clockwork," study lead author Prajwal Niraula, a graduate student in the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology (MIT) in Cambridge, said in a statement.

"Everyone needs a bit of fun these days," co-author Julien de Wit, an assistant professor in the same department at MIT, added in the statement, which was released by the university.

That fun extends to the title of the new paper, which was published online today (Sept. 21) in the The Astronomical Journal: "Pi Earth: a 3.14-day Earth-sized Planet from K2's Kitchen Served Warm by the SPECULOOS Team." 

As its name suggests, K2-315b is the 315th alien world found using K2 data — meaning the discovery team was just one exoplanet away from even more serendipitous symmetry.

Niraula and his colleagues estimate that K2-315b is about 95% as wide as Earth. This size suggests the alien planet is rocky, but this isn't certain at the moment because K2-315b's mass remains unknown. 

K2-315b's host star is just one-fifth the size of our sun and not nearly as hot. But the newfound exoplanet's extreme orbital proximity still makes its surface quite toasty — about 350 degrees Fahrenheit (177 degrees Celsius), the research team estimated.

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

But this temperature is, as the MIT statement notes, perfect "for baking actual pie." (There's another baking tie-in with this study, it should be noted: Speculoos are also a type of spiced shortbread cookie popular in Belgium and other parts of Europe.)




Kepler hunted for alien planets using the "transit method," noting the tiny brightness dips they caused when crossing their host stars' faces from the spacecraft's perspective. This same strategy is employed by Kepler's successor, NASA's Transiting Exoplanet Survey Satellite.

NASA decommissioned Kepler in November 2018 after 5 1/2 years of groundbreaking work. Astronomers have discovered about 4,300 confirmed exoplanets to date, and Kepler, via its primary and K2 missions, is responsible for about two-thirds of those finds. As the new study shows, the Kepler dataset keeps on giving, even though the spacecraft itself has been dead for nearly two years.