A newly discovered exoplanet challenges current models pertaining to planet formation
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Artistic representation of the orbits of the planets around GJ 3512 Credit: Guillem Anglada-Escude - IEEC/Science Wave, using SpaceEngine.org
Astronomers of the CARMENES consortium have discovered a new exoplanet that should not exist according to current knowledge. The research group, which includes the Max Planck Institute for Astronomy (MPIA, Heidelberg), found a gaseous planet whose mass is unusually large compared to its host star GJ 3512. The scientists conclude that this planet probably originated from a gravitationally unstable disk of gas and dust around the then still young dwarf star. This contradicts the currently, widely accepted model of planet formation, which requires a solid core to collect surrounding gas.
Astronomers are certain that planets are a by-product from the process of star formation. They form in the disk from which their parent star also emerged. The predominant model for the formation of planets is based on the notion that an object initially develops from solid particles in the disk. The gravitational pull of this planetary embryo ensures that an atmosphere is formed from the surrounding gas. Now scientists of the CARMENES consortium led by Juan Carlos Morales, a researcher from the Institute of Space Studies of Catalonia (IEEC) at the Institute of Space Sciences (ICE, CSIC), with contributions from Diana Kossakowski and Hubert Klahr (MPIA) have discovered a gas planet similar to Jupiter that contradicts this model. Instead, it seems to have developed directly out of the disk, without a solid nucleus of condensation. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
Simulation of the disk of gas and dust surrounding a young star. Courtesy: Alan Boss
There is an as-yet-unseen population of Jupiter-like planets orbiting nearby Sun-like stars, awaiting discovery by future missions like NASA’s WFIRST space telescope, according to new models of gas giant planet formation by Carnegie’s Alan Boss described in an upcoming publication in The Astrophysical Journal. His models are supported by a new Science paper on the surprising discovery of a gas giant planet orbiting a low-mass star.
“Astronomers have struck a bonanza in searching for and detecting exoplanets of every size and stripe since the first confirmed exoplanet, a hot Jupiter, was discovered in 1995,” Boss explained. “Literally thousands upon thousands have been found to date, with masses ranging from less than that of Earth, to many times the mass of Jupiter.”
But there are still gaping holes in scientists’ knowledge about exoplanets that orbit their stars at distances similar to those at which our Solar System’s gas giants orbit the Sun. In terms of mass and orbital period, planets like Jupiter represent a particularly small population of the known exoplanets, but it’s not yet clear if this is due to biases in the observational techniques used to find them—which favor planets with short-period-orbits over those with long-period-orbits—or if this represents an actual deficit in exoplanet demographics.
All the recent exoplanet discoveries have led to a renewed focus on theoretical planet formation models. Two primary mechanisms exist for predicting how gas giant planets form from the rotating disk of gas and dust that surrounds a young star—bottom-up, called core accretion, and top-down, called disk instability. ...
The Effect of the Approach to Gas Disk Gravitational Instability
on the Rapid Formation of Gas Giant Planets ~ Alan P. Boss
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
