Studying distant star systems helps us understand how unique or, on the contrary, ordinary our solar system is. In addition, it brings us closer to solving the mysteries of the origin of life in the Universe – at least the biological form that we know from terrestrial organisms. The horizons of this knowledge have expanded significantly with the advent of the James Webb Observatory. The latest discovery has once again confirmed its significance – for the first time it was possible to directly register carbon dioxide on a distant exoplanet.
Image source: NASA
Using Webb’s infrared sensors, scientists observed the HR 8799 star system, located 130 light years from Earth. This is a fairly young system, only 30 million years old. At that time, dinosaurs still existed on Earth, although their era was coming to an end. Such young systems have completed the process of planet formation relatively recently, and their stars remain hot and bright, which makes them convenient objects for observation in the infrared range. Both emission and absorption lines are clearly visible in this spectrum, which allows us to determine the composition of substances and molecules with high accuracy even at significant distances.
The Webb Observatory’s coronagraph helped block the light from the central star HR 8799, allowing direct observation of four exoplanets in the system. High-contrast observations revealed carbon dioxide in their atmospheres, among other carbon compounds. These planets are gas giants similar to Jupiter and Saturn. The data collected suggest that the exoplanets formed as a result of accretion, the process of matter falling onto planetary cores. A similar formation mechanism is considered likely for the gas giants of the Solar System.
Previously, scientists had only been able to obtain indirect evidence of the presence of carbon dioxide on the exoplanet WASP-39b. However, observations of HR 8799 were the first time that this key component for the development of biological life was directly detected. Moreover, the technique developed by astronomers for detecting carbon compounds at large distances promises new discoveries that may be vital for understanding our place in the Universe and the prevalence of life in it.