Super bass (8/31/23)

Good afternoon, and happy Thursday. Did you catch the super blue moon last night?

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A New Kind of Neptune

It’s not every day that astronomers spot something in the sky that might be a brand-new, never-seen-before kind of celestial object.

Researchers using TESS (the Transiting Exoplanet Survey Satellite), though, recently found themselves puzzled by a kind of planet they’ve never seen before: a Neptune-sized planet so dense and so close to its star that it seems like it shouldn’t exist. The finding was published yesterday in Nature.

“The discovery of TOI-1853 b implies that large planets can have surprising amounts of heavy elements, much more than previously thought," Luca Naponiello, an astrophysicist at the University of Rome and lead author of the study, told Space.com. "Neptunian planets show an astonishing variety of density and compositions, but we didn't believe they could be so compact."

A hot Neptune: To classify exoplanets (i.e., planets orbiting stars other than the Sun), astronomers use the friendly faces of our own Solar System to compare. An Earth-like exoplanet, for example, would be rocky and roughly the size of Earth. A super-Earth is like Earth, but bigger, and a hot Jupiter is a large gas giant orbiting close to its star, explaining the heat classification.

The planet identified in the study, called TOI-1853 b, is a hot Neptune, meaning that it’s roughly the size of the familiar planet in our solar system and has an atmosphere but hugs its star much more closely. It completes an orbit every 1.24 Earth days.

Defying explanation: When a Neptune-sized planet (or any planet) orbits that close to its star, usually, the intense heat means it can’t hold onto an atmosphere, and when a hot Neptune loses its atmosphere, you’re left with just the rocky core—technically a super-Earth. TOI-1853 b, though, retained its atmosphere.

The research team looked into it. By watching the effect of the planet’s orbit on its host star, they were able to determine it had a mass roughly four times higher than Neptune’s, making it denser than steel.

• That could lead to some super strange conditions. It might be mostly rocky with a very thin atmosphere, or it could be nearly half water—but water in a supercritical state.

• Its formation is also a mystery. Collisions between lots of smaller planets may have led to its creation, or conjunctions between gas giants in eccentric orbits around the star, but neither of these explanations is particularly likely, the researchers admitted.

A big wide wonderful universe: TOI-1853 b asks more questions than it answers right now, and researchers are bound to spend a lot of time trying to figure out exactly what it is that makes this planet on the furthest reaches of the hot Neptune spectrum work.

Other News from the Cosmos

• The OSIRIS-REx recovery team is busy practicing for the asteroid sample return mission to get back.

• Chromium hydride, a particularly heat-sensitive molecule, was spotted on an exoplanet for the first time.

• Sudden ejections of matter from a pulsar are making it switch between two brightness modes when it flashes.

• Neptune’s clouds are disappearing, and the impending solar maximum is likely to blame.

• Satellite data over southeast Asia is helping to characterize rainfall in the pre-monsoon season down to the size of the droplets.

The View from Space

ISRO’s Pragyan rover took a look over its shoulder at the lander, Vikram, which brought it safely to the Moon last week.