Planets are formed in disks of gas and dust that orbit young stars. The MIRI Mid-INfrared Disk Survey (MINDS) led by Thomas Henning aims to establish a representative sample of such disks by exploring their chemistry and physical properties with the help of the Mid-Infrared Instrument (MIRI) on board the James Webb Space Telescope (JWST). A recent study conducted by the team focused on a very low-mass star known as ISO-ChaI 147 and discovered a variety of carbon-bearing molecules in the disk that were previously undetectable from Earth. This research provides valuable insights into the composition of such disks, shedding light on the potential formation of planets in those environments.
One significant finding of the study is the prevalence of carbon-rich gas in the disks around very low-mass stars but the absence of oxygen-rich species such as water and carbon dioxide. This composition differs from what is typically observed in disks around solar-type stars, indicating a distinct evolution process for disks around very low-mass stars. This evolution may have implications for the formation of rocky planets with Earth-like characteristics in those disks, as the conditions are different from those found around more massive stars. The study suggests that rocky planets similar in size to Earth could form more efficiently in these environments.
The researchers also found evidence of a rich hydrocarbon chemistry in the observed disk, including 13 carbon-bearing molecules up to benzene. This abundance of organic molecules in the protoplanetary disk, along with the detection of extrasolar ethane and other compounds, highlights the unique chemistry present in these environments. The data did not show any indication of water or carbon monoxide, further emphasizing the carbon-rich nature of the disk. These findings enhance our understanding of the chemistry and composition of disks around very low-mass stars, providing valuable insights into the potential formation of planets in those regions.
The study’s implications extend to the composition of rocky planets that may form in disks around very low-mass stars. The researchers speculate that such planets would likely have primary atmospheres dominated by hydrocarbon compounds rather than oxygen-rich gases like water and carbon dioxide. This highlights the importance of understanding the composition of protoplanetary disks in different environments to better predict the characteristics of potential exoplanets. The team plans to expand their study to a larger sample of disks around very low-mass stars to further investigate the formation processes of exotic carbon-rich terrestrial planets.
The research was funded through the ERC Advanced Grant “Origins – From Planet-Forming Disks to Giant Planets” and involved scientists from various institutions, including the Max Planck Institute for Astronomy and the University of Groningen. The MIRI consortium, supported by several European countries, played a crucial role in conducting the study, utilizing the capabilities of the JWST to explore the chemistry of planet-forming disks. Overall, the study opens a new window to understanding the formation of planets in diverse environments and sheds light on the unique characteristics of disks around very low-mass stars.
