A research team that included a UChicago graduate student has discovered a planet that is estimated to be twice the size of earth. The planet located 226 light-years away from Earth within a star’s habitable zone.
Moreover, the planet known as K2-288Bb could either be rocky or a gas-rich planet similar to Neptune in our own solar system. Within the system, there are two stars; K2-288Bb orbits the smaller star.
Adina Feinstein, lead author of a paper describing the new planet said, “It’s a very exciting discovery due to how it was found; its equilibrium temperature, which likely is similar to Earth’s; and because planets of this size seem to be relatively uncommon. We probably only know about a handful of planets this size.”
Estimated at about 1.9 times Earth’s size, K2-288Bb is half the size of Neptune. This places it within a recently recognized category called the radius gap. Among planets that orbit close to their stars, there’s a curious dearth of worlds between about 1.5 and two times Earth’s size.
Scientists think this is due to intense starlight eroding away the atmospheres of some planets over time. Since K2-288Bb’s radius places it in this gap, it may provide a case study for how planets evolve within this size range.
The planet has been placed within the ‘Fulton Gap’ category because scientists believe a gap is created due to intense starlight breaking up atmospheric molecules. This phenomenon also erodes the atmosphere of planets.
The study is published in the Astronomical Journal.