IvS Seminar: Thomas Henning (26/02/2026)

Value of the Information & Strength of the Argument

The talk provides a comprehensive overview of recent JWST results on planet formation, with a strong emphasis on infrared spectroscopy of protoplanetary disks. Henning presents a clear narrative of the current theoretical framework, from dust growth to pebble accretion, and supports it with observational evidence. He effectively argues that JWST’s spectral capabilities allow us to probe the inner disk regions where rocky planets form, despite the lack of spatial resolution. The argumentation is solid, based on peer-reviewed results and collaborative efforts. He also highlights surprising findings, such as the high CO2/H2O ratio and the dominance of hydrocarbons in low-mass disks, which challenge existing models. The talk is well-structured and provides valuable insights into the ongoing research.

Scientific Rigor, Source Quality, Title Accuracy

The talk demonstrates high scientific rigor, with references to specific programs (MINDS, GTO) and collaborations. Henning mentions several key papers and results, but does not provide explicit citations in the talk. The title accurately reflects the content, focusing on planet formation with JWST. The speaker is a renowned expert, and the content is consistent with current literature. However, as a seminar, it is a personal synthesis rather than a systematic review, and some results may be preliminary. The adequacy between title and content is excellent.

The title accurately reflects the content: the talk focuses on planet formation with JWST, presenting recent results and future prospects.

8/10

The talk is given by a leading expert in planet formation and JWST science, with a strong track record. The content is based on recent JWST observations and established theoretical models. However, as a seminar, it presents a personal perspective and some results may be preliminary or not yet fully peer-reviewed.

Markers derived by PSI from the transcript: the creator did not define chapters.

• 02:00Introduction and overview of JWST's capabilities and extended lifetime.
• 10:00Discussion of the current planet formation paradigm, including streaming instability and pebble accretion.
• 20:00Presentation of JWST MIRI spectra of protoplanetary disks, highlighting molecular detections.
• 30:00Discovery of hydrocarbon-dominated spectra in low-mass disks.
• 40:00Analysis of PDS 70, including the detection of water in the inner disk despite a deep gap.
• 50:00Discussion of the variability of inner disks and the role of gaps in pebble transport.

• MINDS program — MIRI mid-INfrared Disk Survey, a GTO program observing ~60 protoplanetary disks with JWST.
• PDS 70 observations — JWST observations of the PDS 70 system, revealing water in the inner disk and a potential third planet.
• TW Hydra observations — JWST spectrum of TW Hydra, showing depletion of oxygen and carbon and detection of molecular ions.

• JWST Early Release Science results — General JWST results on exoplanets and disks that align with the talk's findings.
• ALMA observations of protoplanetary disks — Complementary observations that support the structure and composition of disks.

• Some theoretical models of disk gaps — The talk challenges the assumption that gaps always block pebble transport, citing observations that show water in inner disks despite gaps.