Periodic Reporting for period 4 - Origins (From Planet-Forming Disks to Giant Planets)
Reporting period: 2024-04-01 to 2024-12-31
Astronomers have discovered more than 5000 exoplanets orbiting other stars. They show an enormous diversity in their orbital parameters, and their characteristic masses and radii. This diversity is an imprint of the planet formation process occuring in gas-dust disks around young stars. In order to place the solar system in context and to understand the conditions forthe occurence of life on other planets, we are investigating how planet formation proceeds, what the properties of their birthplaces are and how organic and pre-biotic molecules can form under the conditions of interstellar space. The project combines observations with high spatial resolution, using the technique of adaptive optics and interferometry in the infrared and at millimeter wavelengths, laboratory experiments on molecular ices and numerical simulations to better understand the physical and chemical processes in disks and planetary atmospheres.
With the comprehensive spectroscopy program MINDS, using the James Webb Space Telescope mid-infrared instrument MIRI, we characterized the water-content of the inner regions of planet-forming disks around solar-type stars and built a connection to their spatial structure. We revealed a rich hydrocarbon chemistry in disks around low-mass stars which shows the diversity of planet-forming environments. With millimetre interferometry we characterized the physical structure of planet-forming disks and their turbukent-state. Radial velocity and direct imaging studies allowed the characterization of young planet populations coupled to the investigation of their atmosphere. We established a new laboratory facility and investigated the production of pre-biotic molecules and their stability under UV irradiation. Finally, we built a new model of the early Earth and studied the formation of the key molecule HCN, leading to precursors of the RNA.
With the comprehensive spectroscopy program MINDS, using the James Webb Space Telescope mid-infrared instrument MIRI, we characterized the water-content of the inner regions of planet-forming disks around solar-type stars and built a connection to their spatial structure. We revealed a rich hydrocarbon chemistry in disks around low-mass stars which shows the diversity of planet-forming environments. With millimetre interferometry we characterized the physical structure of planet-forming disks and their turbukent-state. Radial velocity and direct imaging studies allowed the characterization of young planet populations coupled to the investigation of their atmosphere. We established a new laboratory facility and investigated the production of pre-biotic molecules and their stability under UV irradiation. Finally, we built a new model of the early Earth and studied the formation of the key molecule HCN, leading to precursors of the RNA.
Our investigations revealed that the radial distribution of planetary embryos and the mass in solid material are the main regulating factors in determing the properties of a planet population. However, the precise measurement of the disk mass is notoriously difficult. We have provided a new approach, independent of the uncertain assumption on gas-dust ratios and dust opacities, by applying dust migration physics. Based on infrared surveys with adaptive-optics assisted instruments we could establish the demographics of planets and could provide mass limits for young planets in disks with inner large gaps and structures. We continued to characterize the exciting young planetary system PDS 70 and found that the two planets are close to a resonance, indicating migration in the disk. In addition, we found the first solid evidence for the presence of a circumplanetary disks around the young exoplanet PDS 70 c. As part of our JWST program MINDS we discovered water in the very inner disk of PDS 70 where rocky planets can form. This is a surprising result because the two giant planets in the system should stop the pebble transport. For a statistical sample of disks around solar-type stars we provided constraints on the water reservoir and established a relation to the geometrical structure of the disks. For low-mass stars we obtained the surprising result that the chemical composition of their inner disk regions are dominated by hydrocarbons and not water. This will lead to a different planet poulation around the low-mass stars. We established comprehensive dynamical disc models, including pebble transport and photoevaporation. We showed that the chemical composition of pebbles is practically not changing during radial transport until the inner evaporation zones are reached. As part of the Carmenes exoplanet surveys, we are detecting low-mass planets around M-type stars. In addition, we characterized successfully the atmosphere composition of exoplanets with high-resolutions spectroscopy. The analysis of exoplanet atmopsheres, including retrieval techniques, allows us to put constraints on the planet formation process.
In our "Origins of Life Lab" we studied the formation of organic molecules under the low-temperature conditions of molecular clouds and the outer regions of protoplanetary disks. Important experimental results are the discovery of a phase transition in CO ice and the detection of a completely new pathway for the formation of peptides. In addition, we were able to reveal synthesis pathways for a variety of pre-biotic molecules and studied the stability of pre-biotic molecules under UV irradiation. Finally, we built a comprehensive model of the early Erath system sand studied the production of HCN and RNA precursors both considering meteoritic infall and internal serpentinization processes.
The ERC grant allowed me to assemble a large and diverse group including PhD students and postdocs. Our Origina lab turned out to be of special attraction for bachelor and master students both with physics and chemsitry background. The project produced close to 200 refereed papers, including papers in Nature, Nature Astronomy and Science. In addition, three members of the group obtained permament faculty positions in Germany, Italy, and China. One group member obtained a research group funded by the Max Planck Society.
In our "Origins of Life Lab" we studied the formation of organic molecules under the low-temperature conditions of molecular clouds and the outer regions of protoplanetary disks. Important experimental results are the discovery of a phase transition in CO ice and the detection of a completely new pathway for the formation of peptides. In addition, we were able to reveal synthesis pathways for a variety of pre-biotic molecules and studied the stability of pre-biotic molecules under UV irradiation. Finally, we built a comprehensive model of the early Erath system sand studied the production of HCN and RNA precursors both considering meteoritic infall and internal serpentinization processes.
The ERC grant allowed me to assemble a large and diverse group including PhD students and postdocs. Our Origina lab turned out to be of special attraction for bachelor and master students both with physics and chemsitry background. The project produced close to 200 refereed papers, including papers in Nature, Nature Astronomy and Science. In addition, three members of the group obtained permament faculty positions in Germany, Italy, and China. One group member obtained a research group funded by the Max Planck Society.
This is the last report and the project has been completed at December 31st. The research with JWST and the lab facility continues and will produce many more exciting results in the coming year.