Distant, 'potentially habitable' planet spotted by citizen scientists
Citizen scientists have unveiled a distant exoplanet that is believed to be roughly twice the size of Earth and located within its star's habitable zone. The exoplanet, named K2-288Bb, could either be a rocky world like Earth or a gas-rich planet like Neptune. Using data from NASA's Kepler space telescope, the new world was found 226 light years from Earth in the constellation Taurus, according to NASA.
“It's a very exciting discovery due to how it was found, its temperate orbit and because planets of this size seem to be relatively uncommon,” Adina Feinstein, lead scientist of the study, said. The new world lies in a stellar system called K2-288 which includes two dim, cool M-type stars that are roughly 8.2 billion kilometres (5.1 billion miles) apart — about six-times the distance between Saturn and the Sun.
The brighter star of the pair is estimated to be half as large and massive as Earth's Sun, while its dimmer companion is about one-third the Sun's mass and size. K2-288Bb orbits the smaller and dimmer star every 31.3 days. Furthermore, the data suggests that K2-288Bb resides within its host star's habitable zone, which means the planet may have liquid water on its surface.
The exoplanet was discovered using data from the fourth observing campaign of Kepler's K2 mission, which ran from 2014 to 2018. Specifically, the research team looked for evidence of periodic changes in stars' brightness which would suggest that an exoplanet passed in front of one of the stars. Using this method the team found evidence of two likely planetary transits in the K2-288 system. Observations of a third transit were needed to confirm the discovery of an exoplanet.
It turned out the team was not utilising all of the spacecraft's data. During its K2 mission Kepler repositioned itself towards a new patch of sky once every three months. There were initial concerns about the accuracy of Kepler's measurements collected during the first few days after it was reoriented in the sky. “That's how we missed it – and it took the keen eyes of citizen scientists to make this extremely valuable find and point us to it,” Feinstein said.