Super-Earths Had a Violent Past, Mini-Neptunes a Gentle One — And Their Orbits Tell the Story
If you could look back in time at a newborn super-Earth and a newborn mini-Neptune, you might not be able to tell them apart. Both are worlds somewhere between the size of our planet and Neptune — a category of planet that doesn’t even exist in our solar system. Both orbit alien suns in the same stellar neighbourhoods. And yet, as a team of Chinese astronomers has now shown, these two types of planet followed radically different life paths. The scars are written in the shapes of their orbits.