As missions like NASA's Hubble Space Telescope, TESS and Kepler continue to provide insights into the properties of exoplanets (planets around other stars), scientists are increasingly able to piece together what these planets look like, what they are made of, and if they could be habitable or even inhabited. In a new study published recently in The Planetary Science Journal, a team of researchers from Arizona State University (ASU) and the University of Chicago have determined that some carbon-rich exoplanets, given the right circumstances, could be made of diamonds and silica. "These exoplanets are unlike anything in our solar system," says lead author Harrison Allen-Sutter of ASU's School of Earth and Space Exploration. Diamond exoplanet formation When stars and planets are formed, they do so from the same cloud of gas, so their bulk compositions are similar. A star with a lower carbon to oxygen ratio will have planets like Earth, comprised of silicates and oxides with a very small diamond content (Earth's diamond content is about 0.001%). https://phys.org/news/2020-09-carbon-rich-exoplanets-diamonds.html