Astronomers discover carbon isotopes in the atmosphere of an exoplanet for the first time

An international team of scientists led by specialists from the Netherlands School of Astronomy became the first in the world who were able to detect carbon isotopes in the atmosphere of an exoplanet.

The study was published in the journal Nature, and briefly tells Phys.org. We are talking about the planet TYC 8998-760-1b, which was discovered just two years ago by Alexander Bohn of Leiden. By the way, he is the co-author of the scientific article.

This planet turned out to be a gas giant, it is located at a distance of 300 light years from Earth in the direction of the constellation Fly. Scientists classified it as a superjupiter, because it is 14 times more massive than the largest planet in the solar system.

For the first time, the team was able to detect the presence of different forms of carbon – isotopes – in the atmosphere of this giant. These are different forms of the same atom, but with different numbers of neutrons in the nucleus. For example, carbon with six protons usually has six neutrons – this is the so-called carbon-12. But sometimes there are seven neutrons (carbon-13) or eight (carbon-14).

The number of neutrons doesn’t change the chemical properties of carbon much, but the isotopes themselves both form differently and react differently to their environment. Modern scientists use carbon isotopes in many fields of science. For example, archaeologists date artifacts with carbon-14. Other isotopes are used in medicine to diagnose cancer and cardiovascular diseases.

In the new study, astronomers used data from observations made with the Very Large Telescope (VLT) of the European Southern Observatory. It is located in Chile. The received signals made it possible to measure and calculate the ratio of different carbon isotopes in the atmosphere of an exoplanet.

The data shows that the studied atmosphere is saturated with carbon-13. It turned out to be twice as much as expected. Astronomers attribute this to the fact that the planet formed at a great distance from its parent star.

“This planet is more than 150 times farther away from its parent star than Earth is from the Sun,” says co-author Paul Moliere of Germany’s Max Planck Institute for Astronomy in Heidelberg. – It may have formed in the presence of large amounts of carbon-13, leading to a higher proportion of this isotope in the planet’s atmosphere today.”

Further research on isotopes will help in understanding the processes of planet formation.