About 212 light-years from Earth, a gas giant enough light to be nicknamed a “super-blown” or “sugar-cotton” planet circulates extremely close to its host star. He exoplanet it is so light that astronomers question everything we previously knew about how gas giants are formed.
This super blown exoplanet, known as WASP-107b, is about the same size as Jupiter, but only about a tenth of the mass, or about 30 times the size of Earth. According to a new study published Monday in The Astronomical Journal, its central mass is significantly smaller than astronomers thought necessary to create a gas giant planet like Jupiter and Saturn.
The discovery, made by the doctorate. student Caroline Piaulet under the supervision of Professor Björn Benneke of the University of Montreal, indicates that gas giants form much more easily than previously thought.
“This study pushes the boundaries of our theoretical understanding of how giant-sized planets form. WASP-107b is one of the most inflated planets out there and we need a creative solution to explain how these small nuclei can build gas envelopes. so big, “co-author Eve Lee said in a statement.
WASP-107b is not a new discovery: astronomers first detected it in the constellation of the Virgin in 2017. The planet is very close to its star, more than 16 times closer than Earth to the sun, completing one orbit every 5.7 days.
WASP-107b is one of the least dense exoplanets scientists have ever found. They have nicknamed similar types of planets – gas giants with sugar cotton density – super cute.
ESA / HUBBLE, NASA, M. KORNMESSER
To find the surprising mass of the planet, astronomers studied the observations obtained at the Keck Observatory in Hawaii. They used a technique called the radial velocity method, which studies the oscillating motion of a planet’s star caused by a planet’s gravitational attraction, in order to calculate mass.
The scientists were surprised to conclude that the solid core of WASP-107b has a mass that is no more than four times that of Earth, that is, more than 85% of its mass comes from the thick gaseous layer that surrounds the core. This is a radically different breakdown from Neptune, which has a similar mass but has only 5% to 15% of it within its gas layer.
Based on their knowledge of Jupiter and Saturn, scientists previously believed that a solid core would need at least ten times the mass of Earth to acquire enough gas for a gaseous giant planet to form. WASP-107b challenges this theory.
“This work deals with the fundamentals of how giant planets can form and grow,” Benneke said. “It provides concrete evidence that the massive accretion of a gas envelope can be triggered for much less massive nuclei than previously thought.”
Lee argues that “the most plausible scenario is that the planet formed very far from the star, where the gas in the disk is cold enough for gas accretion to occur very quickly. The planet was able to migrate to the planet. its current position, either through interactions with the disk or other planets in the system. “
While studying the planet, the team encountered another of the same system, the WASP-107c. It has a mass about one-third that of Jupiter and takes three years to orbit its host star once.
The oval-shaped orbit of the planet suggests that the new hypothesis of astronomers is on the right track.
“The WASP-107c, in some respects, has retained the memory of what happened to its system,” Piaulet said. “Its great eccentricity hints at a rather chaotic past, with interactions between planets that could have caused significant displacements, such as the WASP-107b suspect.”
The team hopes to continue studying the strange planet with the launch of James Webb Space Telescope this year.