Starship Asterisk*

The newfound planet K2-288Bb, illustrated here, is slightly smaller than Neptune. Located about 226 light-years away, it orbits the fainter member of a pair of cool M-type stars every 31.3 days. Credit: NASA/GSFC/Francis Reddy

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Using data from NASA's Kepler space telescope, citizen scientists have discovered a planet roughly twice the size of Earth located within its star's habitable zone, the range of orbital distances where liquid water may exist on the planet's surface. The new world, known as K2-288Bb, could be rocky or could be a gas-rich planet similar to Neptune. Its size is rare among exoplanets - planets beyond our solar system. ...

Located 226 light-years away in the constellation Taurus, the planet lies in a stellar system known as K2-288, which contains a pair of dim, cool M-type stars separated by about 5.1 billion miles (8.2 billion kilometers) - roughly six times the distance between Saturn and the Sun. The brighter star is about half as massive and large as the Sun, while its companion is about one-third the Sun's mass and size. The new planet, K2-288Bb, orbits the smaller, dimmer star every 31.3 days. ...

• Astronomical Journal 157(2):40 (Feb 2019) DOI: 10.3847/1538-3881/aafa70