Kepler-90i

Lore & Background

Kepler-90i was discovered by NASA's Kepler spacecraft using the transit method, which measures the dimming of a star as a planet crosses in front of it. Its detection was aided by deep learning, a class of machine learning algorithms. The planet orbits its host star every 14.45 days at a distance of 0.107 AU, making it very close to the star and likely tidally locked, with one side in permanent daylight and the other in eternal darkness.

With a radius 1.32 times that of Earth, Kepler-90i is classified as a super-Earth and is small enough to be rocky. Assuming an Earth-like composition, its mass would be about 2.3 times Earth's. Its equilibrium temperature of 709 K is similar to the average temperature of Venus. The host star Kepler-90 has a mass and radius 1.2 times that of the Sun, a surface temperature of 6080 K, and an estimated age of around 2 billion years with considerable uncertainty. The star has an apparent magnitude of 14, too dim to be seen with the naked eye.

Reader's Guide

Kepler-90i's significance lies in its role as the eighth planet in the Kepler-90 system, which as of December 2017 holds the record for the most exoplanets discovered orbiting a single star. Its discovery demonstrated the power of deep learning algorithms in analyzing Kepler data, as the planet was found by applying machine learning to light curves that had already been collected. This approach opened a new avenue for identifying exoplanets that might have been missed by traditional methods. The planet's close orbit and likely tidal locking provide a case study for the diversity of planetary environments in compact multi-planet systems. Kepler-90i also contributes to the understanding of super-Earths, showing that such planets can exist in systems with multiple planets in close orbits around a G-type star. Its equilibrium temperature, similar to Venus, highlights the range of conditions possible for rocky exoplanets.