Scientists discover another exoplanet that theories say should not exist
The uncertainty of science: Scientists using telescopes both in orbit and on the ground have discovered a small red dwarf star with only 20% the mass of our Sun with a gas giant exoplanet with about half the mass of Saturn but a bit larger in size.
The problem is that the theory for the formation of such gas giants predicts that they should not form around small red dwarfs such as this star.
The most widely held theory of planet formation is called the core accretion theory. A planetary core forms first through accretion (gradual accumulation of material) and as the core becomes more massive, it eventually attracts gases that form an atmosphere. It then gets massive enough to enter a runaway gas accretion process to become a gas giant.
In this theory, the formation of gas giants is harder around low-mass stars because the amount of gas and dust in a protoplanetary disc around the star (the raw material of planet formation) is too limited to allow a massive enough core to form, and the runaway process to occur.
Yet the existence of TOI-6894b (a giant planet orbiting an extremely low-mass star) suggests this model cannot be completely accurate and alternative theories are needed.
You can read the paper here. The exoplanet orbits the star every 3.37 days, and each transit across the face of the star has been easily detected by numerous telescopes. Further spectroscopic observations using the Webb Space Telescope will be able to characterize the exoplanet’s atmosphere more fully.
The uncertainty of science: Scientists using telescopes both in orbit and on the ground have discovered a small red dwarf star with only 20% the mass of our Sun with a gas giant exoplanet with about half the mass of Saturn but a bit larger in size.
The problem is that the theory for the formation of such gas giants predicts that they should not form around small red dwarfs such as this star.
The most widely held theory of planet formation is called the core accretion theory. A planetary core forms first through accretion (gradual accumulation of material) and as the core becomes more massive, it eventually attracts gases that form an atmosphere. It then gets massive enough to enter a runaway gas accretion process to become a gas giant.
In this theory, the formation of gas giants is harder around low-mass stars because the amount of gas and dust in a protoplanetary disc around the star (the raw material of planet formation) is too limited to allow a massive enough core to form, and the runaway process to occur.
Yet the existence of TOI-6894b (a giant planet orbiting an extremely low-mass star) suggests this model cannot be completely accurate and alternative theories are needed.
You can read the paper here. The exoplanet orbits the star every 3.37 days, and each transit across the face of the star has been easily detected by numerous telescopes. Further spectroscopic observations using the Webb Space Telescope will be able to characterize the exoplanet’s atmosphere more fully.
