New Kepler Discovery: Five Alien Planets in Ancient Star System from the Dawn of the Milky Way

By: Wendy on 08:14

Kepler's ultra-precise, long-duration photometry is ideal for detecting systems with multiple transiting planets. These systems provide important data for understanding the dynamics, formation, and evolution of planetary systems. The fascinating YouTube video below presents a detailed analysis of an extremely compact and old five-planet system around a seismic K dwarf (KOI-3158, HIP 94931).

KOI-3158 is a bright, high-proper motion, main-sequence star of spectral type K0. Its overabundance of alpha elements and peculiar kinematics make it a member of the Galactic thick disk. Interestingly enough, it belongs to the Arcturus stellar stream, a moving group originally thought to be of extragalactic origin, but nowadays interpreted as arising from dynamical perturbations within the Galaxy.

The detection of a bound M-dwarf pair means that KOI-3158 is part of a hierarchical triple system. The target star oscillates, being the densest star with detected solar-like oscillations found to date (i.e., having the highest large frequency separation). We provide precise stellar properties from grid-based modeling, including an asteroseismic age of ~12 Gyr.

All five planets in the system have been validated as sub-Earth-sized, with the innermost planet being similar in size to Jupiter and the Solar System's largest moon, Ganymede. Remarkably, this is the most compact system ever found, being characterized by a concentration of dynamically packed planets below 0.1 AU with adjacent planet pairs lying close to strong 5:4, 4:3, 5:4, and 5:4 orbital resonances.

The NASA image at the top of the page shows the orange dwarf Gliese 710. Orange dwarf stars, or K-type main-sequence stars, are considered best bets for supporting extraterrestrial life. They remain stable in the main phase longer than our Sun, allowing more time for life to form on orbiting planets and emitting enough radiation in the non-UV ray spectrum to provide a temperature which allows for liquid water.