This strange ‘super-puff’ planet is more atmosphere than core

By Georgina Torbet Published April 28, 2022

An artist’s impression of WASP-107b. — An artist’s impression of WASP-107b. NASA / ESA / Hubble / M. Kornmesser

While most planets we’ve discovered outside our solar system have been rocky worlds like Earth, gas giants like Jupiter, or ice giants like Uranus, these aren’t the only types of planets out there. There are also some strange “super-puff” planets that are so low in density that they are also called cotton candy planets. Now, new research into one of these super puffs shows it is even odder than previously thought.

Planet WASP-107b has a mass just one-tenth that of Jupiter, even though it is around the same size. It also orbits very close to its star, with a year there lasting only 5.7 days.

Recommended Videos

But the really strange thing about this planet has to do with its atmosphere. The layer of gas around the planet makes up more than 85% of its mass, meaning the planet’s core must be tiny, with a mass of just four times the mass of Earth.

Please enable Javascript to view this content

This raises questions about what is keeping the atmosphere in place.

“We had a lot of questions about WASP-107b,” said Caroline Piaulet, a Ph.D. student in the Institute for Research on Exoplanets at the Université de Montréal, in a statement. “How could a planet of such low-density form? And how did it keep its huge layer of gas from escaping, especially given the planet’s close proximity to its star?”

The researchers think that the only way such an odd planet could exist is if it formed elsewhere and moved over time. “For WASP-107b, the most plausible scenario is that the planet formed far away from the star, where the gas in the disk is cold enough that gas accretion can occur very quickly,” explained Professor Eve Lee, an astronomer in the Department of Physics and the McGill Space Institute at McGill University. “The planet was later able to migrate to its current position, either through interactions with the disc or with other planets in the system.”

This theory is supported by the detection of another planet in the system, called WASP-107c, which has an eccentric orbit. This suggests that the system has a “chaotic past,” according to Piaulet, which pushed the planets into different positions.

The research is published in the Astronomical Journal.

Topics

Georgina Torbet

Space Writer

Georgina has been the space writer at Digital Trends space writer for six years, covering human space exploration, planetary…

Space

James Webb investigates a super puffy exoplanet where it rains sand

$Artistic concept of the exoplanet WASP-107b and its parent star. Even though the rather cool host star emits a relatively small fraction of high-energy photons, they can reach deep into the planet’s fluffy atmosphere.$

Exoplanets come in many forms, from dense, rocky planets like Earth and Mars to gas giants like Jupiter and Saturn. But some planets discovered outside our solar system are even less dense than gas giants and are a type known informally as super-puff or cotton candy planets. One of the least dense exoplanets known, WASP-107b, was recently investigated using the James Webb Space Telescope (JWST) and the planet's weather seems to be as strange as its puffiness.

The planet is more atmosphere than core, with a fluffy atmosphere in which Webb spotted water vapor and sulfur dioxide. Strangest of all, Webb also saw silicate sand clouds, suggesting that it would rain sand between the upper and lower layers of the atmosphere. The planet is almost as big as Jupiter but has a tiny mass similar to that of Neptune.

Space

Chocolate mousse in space is more important than you think

Astronaut Andreas Mogensen with his chocolate mousse aboard the space station.

Astronauts on board the International Space Station (ISS) keep a busy schedule during their six-month stints in orbit. Most of their time is taken up with carrying out scientific research in the unique microgravity conditions that the facility provides, while the occasional spacewalk takes care of upgrades and general maintenance.

The research programs include learning about the best way to grow crops off-Earth and aboard the relatively cramped conditions of the orbital facility, an especially important task if we’re ever to send astronauts on long-duration missions to a lunar base or even to Mars.

Space

Webb spots water vapor in a planet-forming disk

An artist's concept portraying the star PDS 70 and its inner protoplanetary disk.

One of the big open questions about Earth and how life formed here is where the planet's water came from. Water is essential to life as we know it, but many scientists think that water did not originally form on Earth -- rather, it may have been carried here by asteroids. Recently, though, astronomers have discovered water vapor in the planet-forming region of a star, suggesting that future planets which form here might have access to water right from the start.

The study used the James Webb Space Telescope to look at star PDS 70, which is cooler and much younger than our sun. The star has two gas giant planets orbiting it, but it is also still forming planets and has two protoplanetary disks of dust and gas swirling around it. The inner disk, which is in a region comparable to the distance of the Earth from the sun, is where the water vapor was detected.