Unusual CO₂-rich disk detected around young star challenges planet formation models

A study led by Jenny Frediani at the University of Stockholm revealed a planet training disc with an unusual chemical composition: an abundance of unexpected carbon dioxide (CO (CO₂) In regions where earth -shaped planets can one day form.

The discovery, made using the James Webb space telescope (JWST), calls into question the long -standing hypotheses on the chemistry of planetary birthplaces. The study is published in Astronomy and astrophysics.

“Unlike most planet’s training discs nearby, where water vapor dominates the interior regions, this disc is surprisingly rich in carbon dioxide,” explains Jenny Frediani, PH.D. Student in the Astronomy Department of the University of Stockholm.

“In fact, water is so rare in this system that it is barely detectable – a spectacular contrast with what we generally observe.”

A newly formed star is initially deeply anchored in the gas cloud from which it was formed and creates a disc around itself where the planets can in turn form. In the conventional models of the planet’s formation, pebbles rich in water ice derive from the cold outdoor disc towards the warmer interior regions, where the increase in temperatures causes the sublimation of ICEs.

This process is generally translated into strong water vapor signatures in the interior areas of the disc. However, in this case, the JWST / Miri spectrum shows a signing of confusing carbon dioxide instead.

“This calls into question the current chemistry and disc development models, because the high levels of carbon dioxide compared to water cannot be easily explained by the evolution processes of the standard disc,” explains Frediani.

Arjan Bik, researcher from the Astronomy Department of the University of Stockholm, adds: “Such an abundance of carbon dioxide in the planet’s formation area is unexpected. It indicates the possibility that the intense ultra -seconded massive stars – either from the host star or the neighboring massive stars – is summarized by the chemistry of Disk.”

Researchers have also detected rare isotopic variants of carbon dioxide, enriched with carbon-13 or oxygen isotopes ¹⁷O and ¹⁸O, clearly visible in JWST data. These isotopologists could offer essential indices on long -standing issues on unusual isotopic fingerprints found in meteorites and comets – of the formation of our own solar system.

This co₂-The rich disc was found in the massive region of stars formation NGC 6357, located about 1.7 kiloparsecs (about 53 miles of kilometers). The discovery was made by the Extreme Ultraviolet Environmental collaboration (Xue), which focuses on the intense impact of radiation fields.

Maria-Claudia Ramirez-Vannus from Max Planck Institute for Astronomy in Heidelberg and responsible for Xue collaboration, says it is an exciting discovery. “It reveals to what extent extreme radiation environments – common in massive stars formation regions – can modify the constituent elements of the planets. Since most stars and probably most planets are formed in such regions, understanding these effects is essential to grasp the diversity of planetary atmospheres and their habitability potential.”

Thanks to the JWST Miri instrument, astronomers can now observe distant and rolled discs of dust with unprecedented details on infrared wavelengths – providing critical and chemical conditions that govern the formation of the planet.

By comparing these intense environments with quieter and more isolated regions, researchers discover the environmental diversity that shapes emerging planetary systems.

Astronomers of the University of Stockholm and Chalmers have helped to develop the Miri instrument, which is a camera and a spectrograph which observes the infrared radiation of the average wavelength of 5 microns at 28 microns. He also has coronagrapists, specially designed to observe exoplanets.