Research: some exoplanets may be made of diamonds

Scientists from the United States have created a model that showed that some exoplanets are composed of diamonds. According to scientists, if “diamond” planets really exist, most likely, they do not have the conditions for the origin of life.

In a new study published in The Planetary Science Journal, a group of researchers from Arizona State University (ASU) and the University of Chicago have determined that some carbon-rich exoplanets, under certain circumstances, can form their composition from diamonds and silica.

“These exoplanets are unlike anything in our solar system,” said lead author Harrison Allen-Sutter, who participated in the study. When stars and planets form, they do this from the same gas cloud, so their bulk compositions are similar. In a star with a lower carbon-to-oxygen ratio, planets like Earth will be composed of silicates and oxides with very low diamond content (the Earth has a diamond content of about 0.001%). However, under other conditions, the ratios can be very different from the composition to which the researchers are accustomed.

In the presence of water, these planets can turn into a diamond. To test their theory, the scientists immersed silicon carbide in water and clamped the sample to very high pressure, and then heated the sample to a very high temperature with a laser. Simultaneously, they took x-ray measurements of the sample.

As they predicted, at high temperature and pressure, silicon carbide reacted with water and turned into diamonds and silica (silicon dioxide). According to scientists, if the “diamond” planets do exist, most likely, they lack the conditions for the origin of life.