A Venus-Mass Planet Orbiting a Brown Dwarf: Missing Link between Planets and Moons

TL;DR

This paper reports the discovery of a Venus-mass planet orbiting a brown dwarf, suggesting similar formation processes for planets and moons across different celestial systems.

Contribution

It presents the first known system of a Venus-mass planet orbiting a brown dwarf, bridging the understanding of planet and moon formation mechanisms.

Findings

Discovery of a Venus-mass planet orbiting a brown dwarf

Similar scaled masses and separations across planets, moons, and sub-stellar objects

Support for common formation processes in accretion disks around stars, brown dwarfs, and planets

Abstract

The co-planarity of solar-system planets led Kant to suggest that they formed from an accretion disk, and the discovery of hundreds of such disks around young stars as well as hundreds of co-planar planetary systems by the Kepler satellite demonstrate that this formation mechanism is extremely widespread. Many moons in the solar system, such as the Galilean moons of Jupiter, also formed out of the accretion disks that coalesced into the giant planets. We report here the discovery of an intermediate system OGLE-2013-BLG-0723LB/Bb composed of a Venus-mass planet orbiting a brown dwarf, which may be viewed either as a scaled down version of a planet plus star or as a scaled up version of a moon plus planet orbiting a star. The latter analogy can be further extended since they orbit in the potential of a larger, stellar body. For ice-rock companions formed in the outer parts of accretion disks, like Uranus and Callisto, the scaled masses and separations of the three types of systems are similar, leading us to suggest that formation processes of companions within accretion disks around stars, brown dwarfs, and planets are similar.