Chapter 1: The Search for Exoplanets

As our exploration of the cosmos continues, we uncover a growing number of exoplanets. Many of these findings are significant due to their Earth-like characteristics or the sheer number of planets found within a single solar system. However, K2–315b stands out for its peculiar orbital duration. Completing an orbit around its star in just 3.14 Earth days, it has rightfully earned the nickname “pi planet.”

The origin of its name is reflective of its discovery sequence. This planet is the 315th exoplanet identified through data collected during the Kepler K2 mission. The mission's second phase was initiated after various components of the original Kepler spacecraft failed, which affected its ability to maintain a stable viewing direction. Despite these challenges, NASA cleverly utilized solar wind to partially stabilize Kepler during specific segments of its orbit.

Kepler employed the transit method to identify planets, which involves long-term monitoring of distant stars for light fluctuations. These dips in brightness can indicate that a planet has crossed in front of the star, designated as EPIC 249631677. The transit method is particularly adept at detecting larger planets that orbit closely to their stars. Even though Kepler has ceased operations, research teams, including those at MIT, continue to analyze its extensive dataset for new discoveries akin to K2–315b.

Astronomers have deduced that K2–315b is approximately 0.95 times the radius of Earth, although its mass remains uncalculated. Despite its Earth-like size, the planet’s conditions are likely inhospitable. Positioned nearer to its star than Mercury is to the Sun, K2–315b experiences scorching surface temperatures of around 350 degrees Fahrenheit (176 degrees Celsius). According to MIT, that’s hot enough to prepare actual pies!

To confirm the existence of this planet, researchers often require more than just K2 mission data. The MIT team utilized the SPECULOOS telescope array, composed of five 1-meter telescopes (four located in Chile and one on the largest Canary Island). After determining an optimal time to observe a likely transit, they focused their telescopes on EPIC 249631677. They successfully identified the pi planet during their observations.

The star hosting K2–315b is situated approximately 185 light-years from Earth, a relatively short distance in astronomical terms. Future technologies like the James Webb Space Telescope may provide enhanced insights into this intriguing rocky planet and its mathematical significance.

Now read: Scientists Discover the First Planet Orbiting a Dead Star, New AI Accelerates Calculations of Distant Planet Orbits, Researchers Find a ‘Mirror Image’ of Our Solar System.