New Branch in Family Tree of Exoplanets Discovered

摘要

Since the mid-1990s, when the first planet around another Sun-like star was discovered, astronomers have been amassing what is now a large collection of exoplanets - nearly 3,500 have been confirmed so far. In a new Caltech-led study, researchers have classified these planets in much the same way that biologists identify new animal species and have learned that the majority of exoplanets found to date fall into two distinct size groups: rocky Earth-like planets and larger mini-Neptunes. The team used data from NASA's Kepler mission and the W.M. Keck Observatory.