Catalog brings together the weirdest planets from outside the Solar System

Two studies published this month by researchers at UC Santa Cruz revealed more information about exoplanets — those that orbit stars outside our Solar System — and its oddities.

The first study, published this Wednesday (29) in Astrophysical Journal Supplementcataloged 126 confirmed and candidate exoplanets discovered with NASA’s Transiting Exoplanet Survey Satellite (TESS), in collaboration with the WM Keck Observatory in Hawaii.

The second was published on May 20 in the magazine Naturegives more details about the “inflated” planets, discovered by data from NASA’s James Webb Space Telescope, combined with previous observations from the Hubble Space Telescope.

A super dense planet

Among the 126 exoplanets listed, there is TOI-1824bone of the densest planets catalogued.

“At nearly 19 times the mass of Earth but just 2.6 times the size of our home planet, TOI-1824b is an exoplanetary rarity,” said Joseph Murphy, study co-author and doctoral candidate in astronomy and astrophysics at UC Santa Cruz. “Planets of similar size typically have a mass between about six and 12 times the mass of Earth.”

Two hypotheses raised by scientists to explain a planet with such a large mass for its size: a core similar to Earth’s, surrounded by a thin atmosphere dominated by hydrogen; or a water-rich core with a vapor atmosphere.

“This super-dense planet could be a more massive cousin of water worlds, which are small planets believed to have high water content, and which are thought to exist around red dwarf stars,” Murphy added.

Red dwarfs are the most common type of star in the Milky Way and are a good guide to looking for possibly habitable planets. Because they are colder than our Sun, they allow planets closer to them to have conditions for the existence of liquid water.

“Cotton Candy” Planet

The second study also deepened knowledge about a gas giant that is “inflated”, that is, with a large volume and little mass: the WASP-107b.

The research indicates that the planet’s temperature could be so high due to tidal heating — the influence of one celestial body on another — caused by WASP-107b’s non-circular orbit, which leads to a deformation of its shape, leaving the “stretched” planet.

As the distance between the planet and its star changes continuously throughout the orbit, the gravitational attraction also changes, deforming the planet and generating its heating.

With more than three-quarters of the volume of Jupiter and less than a tenth of the mass, this exoplanet is one of the least dense planets known, with its density compared to that of cotton candy by scientists.

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