NASA puzzles over why some exoplanets are shrinking

[Judi Lynn]

Yes, shrinking.
By Elisha Sauers on November 16, 2023



The gap in exoplanet sizes could be caused by certain mini Neptunes actually shrinking over time. Credit: NASA / ESA / CSA / D. Player (STScI) illustration


As astronomers have used large telescopes to scan the skies for exoplanets, they've noted something odd: Worlds of a certain size are conspicuously missing in space.

The number of confirmed exoplanets — planets orbiting stars other than the sun — has risen to 5,539, according to NASA, with over 10,000 more candidates under review. But exoplanet hunters believe the universe is likely teeming with many trillions of planets.

These exoplanets come in different sizes. Of the midsize worlds, they are mostly divided into two groups, known as super-Earths and mini Neptunes (or sometimes sub-Neptunes). Although both kinds are larger than Earth and smaller than Neptune, super-Earths can be as much as 1.75 times the size of our home planet, and mini Neptunes are double to quadruple the size of Earth.

But if worlds were lined up in order of size, there would be a noticeable gap smack-dab in between super-Earths and mini Neptunes — planets that are about 1.5 to 2 times the size of Earth.

More:
https://mashable.com/article/nasa-kepler-exoplanets-shrinking

[Blue Owl]

1. They were in the pool!