Study: Low-mass stars show distinct planet-forming disks unlike any other

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The MIRI Mid-Infrared Disk Survey (MINDS), led by researchers at the Max Planck Institute for Astronomy, aims to study the chemistry and physical properties of planet-forming disks using the James Webb Space Telescope (JWST). A recent study focused on the vicinity of a very low-mass star, ISO-ChaI 147, reveals significant findings about the composition of these disks.

JWST's advanced instruments allowed the researchers to detect weak emissions from less abundant molecules previously undetectable from Earth. The study found that the gas in the disk surrounding ISO-ChaI 147 is enriched with carbon-bearing molecules and lacks oxygen-rich species. This contrasts sharply with disks around solar-type stars, where oxygen-rich molecules like water and carbon dioxide are predominant. This difference suggests that disks around low-mass stars evolve distinctively from those around more massive stars.

The study indicates that disks around very low-mass stars may be more conducive to forming rocky planets similar in size to Earth rather than gas giants like Jupiter. The distribution of the material in these disks favours the formation of terrestrial planets, although their primary atmospheres may be rich in hydrocarbons rather than oxygen-based gases.

JWST's observations also revealed the most complex hydrocarbon chemistry in a protoplanetary disk seen to date, detecting 13 carbon-bearing molecules, including the first extrasolar ethane. However, the disk showed no signs of water or carbon monoxide.

The findings highlight the need to explore a broader range of disks around very low-mass stars to understand how familiar these carbon-rich environments are and how they affect planet formation. Future studies will focus on expanding this research and analyzing additional data to fully interpret these observations and the formation processes of these molecules.