K2-288B b is an intriguing world located approximately 226 light-years away in the constellation Taurus. It is unique because it orbits in a binary star system (a system with two suns).
Key Physical Characteristics
- Planet Type: Terrestrial (rocky) Super-Earth.
- Size: It is roughly 1.9 times the radius of Earth, placing it in the “radius gap” between Earth-sized worlds and mini-Neptunes.
- Orbit: It completes one orbit around its star every 31.4 Earth days.
- The Star: It orbits the smaller of the two stars in the system, a cool M-dwarf (K2-288B). The two stars are separated by a massive distance (about 6 times the distance from the Sun to Saturn).
Habitability & Environment
In Lisa Kaltenegger’s research, K2-288B b is a primary target for studying the limits of a habitable atmosphere:
- Location: It sits right in the Habitable Zone of its small red dwarf sun.
- Energy Intake: It receives a level of starlight similar to what Earth gets from the Sun, making it a “temperate” candidate for liquid water.
- Atmosphere: Because its size is nearly double that of Earth, it likely has a very thick atmosphere. Scientists are eager to know if this is a life-friendly atmosphere or a crushing, gas-heavy envelope.
Scientific Significance
- Citizen Science Discovery: This planet was famously discovered by citizen scientists (volunteers) who were looking through NASA’s Kepler data as part of the “Exoplanet Explorers” project.
- Binary System Evolution: It provides a rare look at how a habitable planet forms and survives in a system with two stars. The gravity and radiation of the second, more distant star add complexity to its climate.
- The Radius Gap: Because its size is right in the middle of the “Super-Earth” and “Mini-Neptune” categories, it helps Kaltenegger and her team understand exactly where the cutoff for a rocky, habitable surface lies.
