Key takeaways:

— Astronomers at UC Santa Cruz have developed a new model to better understand “steam worlds,” or water-rich sub-Neptunes – some of the most common planets in the universe.

— These planets are too hot for surface oceans and are thought to have atmospheres consisting of exotic phases of water. They are also 10 to 100 times more massive than the icy moons in our solar system that have historically served as models.

— The James Webb Space Telescope has already detected steam on several sub-Neptunes, and the new models will help scientists interpret what telescopes observe from the atmospheric data collected.

Four and a half billion years ago Jupiter rapidly grew to its massive size. Its powerful gravitational pull disrupted the orbits of small rocky and icy bodies similar to modern asteroids and comets, called planetesimals. This caused them to smash into each other at such high speeds that the rocks and dust they contained melted on impact and created floating molten rock droplets, or chondrules, that we find preserved in meteorites today. Now, researchers at Nagoya University in Japan and the Italian National Institute for Astrophysics (INAF) have for the first time determined how these droplets formed and accurately dated the formation of Jupiter based on their findings. Their study, published in Scientific Reports, shows how the characteristics of chondrules, particularly their sizes and the rate at which they cooled in space, are determined by the water contained in the impacting planetesimals. This explains what we observe in meteorite samples and proves that chondrule formation was a result of planet formation. 

Images taken with the MIRI infrared camera on the James Webb Space Telescope (JWST) have made it possible to observe the first galaxies in long-wavelength infrared light for the first time. Alongside a recent study published in Astronomy and Astrophysics, these images provide new insights into how the first galaxies formed over 13 billion years ago.

 Three new papers reveal yet more secrets from samples collected by the University of Arizona-led OSIRIS-REx mission from asteroid Bennu. Among them: Solids that formed close to the sun and stardust from beyond our solar system, as well as materials transformed by interactions with water and the harsh space environment.