Carbon-rich exoplanets can be made of diamonds


Depiction of a carbon-rich planet with diamonds and silica as the main minerals. Water can transform a carbide planet into a diamond-rich planet. In the interior, the main mineral will be diamonds and silica (a layer with crystals in the illustration). The core (dark blue) may be an iron – carbon alloy. Credit: Shim / ASU / Vectizy

As NASA’s Hubble Space Telescope, missions such as 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, they What have been created, and if they can become habitable or even inhabited.


In a recently published study 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 may be made of diamonds and silica, given the right conditions.

“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 with the same cloud of gas, so their bulk compositions are the same. A star with a low carbon to oxygen ratio would have planets like Earth, which would contain silicates and oxides with very low diamond content (about 0.001% of the Earth’s diamond content).

But we are more likely to contain exoplanet carbon around stars with a higher carbon ratio than the Sun. Allen-Sutter and co-authors Emily Garhat, along with Kurt Linenweber and ASU’s Dan Shim, Vitaly Prakapenka and Aran Greenberg of the University of Chicago, hypothesized that these carbon-rich exoplanets could turn into diamonds and silicates, if water (which is abundant Is in quantity) were present (in the universe), a diamond-rich composition.

Carbon-rich exoplanets can be made of diamonds

In the Diamond-Evil cell, two gemstone-quality single crystal diamonds are shaped into an Evil (flat top in the photo) and then face each other. Samples are loaded between coffins (flat surfaces), then samples are compressed between anil. Sincerely: Shim / ASU

Diamond-Evil and X-rays

To test this hypothesis, the research team needed to mimic the interior of a carbide exoplanet using high heat and high pressure. To do this, he used high-pressure diamond-anvil cells in co-author Shim’s laboratory for material from Earth and planets.

First, they dipped silicon carbide in water and compacted the sample between diamonds at very high pressures. Then, to monitor the reaction between silicon carbide and water, they conducted laser heating at the Argonne National Laboratory in Illinois, taking X-ray measurements while the laser heated the sample at high pressure.

As they predicted, with high heat and pressure, silicon carbide reacted with water and turned to diamond and silica.

Carbon-rich exoplanets can be made of diamonds

An uncharged carbon planet (left) changes from a silicon carbide dominated mantle to a silica and diamond dominated mantle (right). The reaction also produces methane and hydrogen. Sincerely: Harrison / ASU

Habitat and Housing

So far, we have not found life on other planets, but the search continues. Planetary scientists and astronomers are using sophisticated instruments in space and on Earth to find the right planets and planets with the correct location around their stars where life can exist.

Carbon-rich exoplanets can be made of diamonds

The cylinder-shaped objects in this picture are Diamond Evil Cells. The diamond-anvil cells are placed in copper holders and then inserted into the synchrotron X-ray / laser beam path. The photo shows diamond-anvil cells and mounts before aligning for X-ray / laser experiments. Sincerely: Shim / ASU

For the carbon-rich planets that are the focus of this study, however, they do not have the necessary properties for life.

While the Earth is geologically active (an indicator habitat), the results of this study suggest that carbon-rich planets are too hard to be geologically active and that a lack of geological activity can make atmospheric composition uninhabitable. The atmosphere is important to life because it provides us with air to breathe, protection from the harsh environment of space and even pressure to allow liquid water.

“Regardless of habit, this is an additional step in helping us to enhance and improve the exoplanets’ comments,” says Allen-Sutter. “The more we learn, the better we will be able to interpret new data from upcoming future missions such as the James Webb Space Telescope and the Nancy Grace Roman Space Telescope so that the world can be understood beyond our own solar system.”


Scientists study galaxy’s ‘water world’


more information:
H. Allen-Sutter et al., Inner Oxidation of Carbide Exoplanets, The Planetary Science Journal (2020). DOI: 10.3847 / PSJ / abaa3e

Provided by Arizona State University

Quotes: Carbon-containing exoplanets can be made of diamonds (2020, 11 September) from 11 September 2020 https://phys.org/news/2020-09-carbon-rich-exoplanets-diamonds.html

This document is subject to copyright. No part may be reproduced without written permission, except for any impartial behavior intended for personal study or research. The content is provided for information purposes only.