This special session aims to prepare the astrophysics community for the exploitation of the revolutionary capabilities of the Extremely Large Telescope (ELT) and their complementarity with the James Webb Space Telescope (JWST). While the main infrastructure of the ELT in Chile is progressing rapidly, the assembly of its dome and instruments are approaching reality. Scheduled for first light in 2029, the ELT, with its 39-meter primary mirror, will be the largest optical telescope in the world. It will host a diverse suite of instruments, including MICADO, HARMONI, METIS, and MORFEO, followed by MOSAIC and ANDES after 2030. The ELT's instruments will offer unique spatial and spectral resolution across a wide wavelength range, opening unprecedented opportunities to study star formation processes and protoplanetary disks, in synergy with JWST observations. Together, these observatories will allow us to explore themes such as:

- Characterization of stellar environments: combining JWST's high-resolution chemical data on H II regions and Photo-Dissociation Regions interfaces with ELT's spatial and spectral capabilities to probe physical conditions and dynamics in these regions.

- Early stages of star and planet formation: detection and analysis of fine structures in disks; detailed observations of pre- and proto-stellar cores enabled by ELT's contrast and high spatial resolution.

- Role of extreme environments: understanding the impact of UV radiation on disk evolution, especially in high stellar density regions.

This 2026 special session will initiate discussions focusing on:

- Observational strategies: methodologies to maximize synergies between JWST and ELT.

- Common tools: needed software for joint analysis of ELT and JWST data.

- Modeling: producing synthetic observations and new models tailored to future instruments? capabilities. In addition, there is also the need for advanced modeling on chemical and physical processes at play in star and planet formation.

- Priority science programs: identifying key ELT programs, considering both guaranteed and open time, as well as interactions with other facilities such as ALMA, VLT/VLTI, and Gaia.

One output of this session would be to establish a collaboration working together on those aforementioned points. This collaboration may work together and help structure the community on different aspects of science and future proposals.

Programme

• Science cases (stellar environment, planet formation and disk evolution)
• Modeling (synthetic observation as well as physical and chemical models of processes at play)
• observational strategies and common tools needed

• Block 1: 30 minutes invited talk followed by 4*15 minutes contributed talks
• Block 2: 6*15 minutes contributed talk
• Block 3: Concluding remarks followed by 1 hour discussion

Invited speakers

Scientific organisers

• Ilane Schroetter (IRAP, CNRS/Univ. de Toulouse)
• Karine Perraut (IPAG, CNRS/Univ. Grenoble Alpes)
• Thomas Haworth (Queen Mary University of London)
• Mari-Liis Aru (Imperial College London)

Contact

ilane.schroetter @ gmail.com