Greg Gerkens is a New York professional who has held education administrative roles and taught Earth sciences. One area in which Greg Gerkens has a long-standing interest is astronomy, including events and phenomena spanning the cosmos.

A recent Astronomy article brought focus to emerging insights into the possible diversity of exoplanets across the galaxy. While our solar system has two basic types of planets, rocky inner ones and gaseous outer ones, a variety of other planet types may exist in solar systems beyond our own.

These include “super-Earths” that contain as much as four times the mass of the Earth and have a radius as much as 1.6 times larger. Another postulated planet type is the “mini-Neptune,” which has a mass 10 times or larger than the Earth. Because they are too large to be rocky planets, mini-Neptunes were assumed to be composed of helium and hydrogen, like the gas giants in this solar system.

A new study suggests that mini-Neptunes may consist of rocky cores, surrounded by extremely thick water atmospheres. These irradiated ocean planets would have been created through an intensive greenhouse effect that occurred when the host star boiled water on the planet surface. This would prevent the planet mass from expanding at the same time that the radius grew several times larger.