By Nadia Drake
Planet hunters have unlocked a treasure chest of alien worlds to reveal more than 50 newly discovered planets, including at least 16 not much bigger than Earth and one small, sparkling nugget: a 3.6-Earth-mass planet, parked just inside its star’s life-friendly zone.
“We can say that most of the stars have planets, and most of them have low-mass planets,” says astronomer Francesco Pepe, a member of the Geneva Observatory’s HARPS team that presented their new finds September 12 during the Extreme Solar Systems conference in Moran, Wyoming. HARPS finds distant worlds by focusing on wobbly stars that are being pulled in different directions by orbiting bodies. The update brings the team’s eight-year discovery total to more than 150 planets.
An accompanying study that will appear in an upcoming issue of Astronomy & Astrophysics presents the team’s long-awaited characterization of its planetary population – and suggests that more than 50 percent of sunlike stars sport a planet. The little guys among them – with masses between Earth’s and Neptune’s – occur primarily in planetary systems. The latest planet dump suggests that roughly 70 to 80 percent of low-mass planets might live in multiplanet neighborhoods, Pepe says.