From Disk Formation to Exoplanetary Systems

Session

Afternoon Session

Sep 22, 2025, 1:30 PM

Eridanus Auditorium (ESO Headquarters)

8. A closer look at the building blocks of planetesimals: characterizing the dust content of protoplanetary disks

Enrique Macias (ESO)

9/22/25, 1:30 PM

The dust content of protoplanetary disks plays a crucial role in the planet formation process. The key ingredients are not only the total budget of solid mass and the dust particle size distribution, but also how these are distributed throughout the protoplanetary disk. Characterizing the dust surface density, particle properties, and size distribution within the disk and its substructures is,...

5. Evidence for Ongoing Planetesimal Formation in Protoplanetary Disks

Sebastian Stammler (LMU)

9/22/25, 1:45 PM

High-resolution ALMA observations of protoplanetary disks commonly reveal multiple narrow rings. Surprisingly, many of these rings exhibit similar moderate optical depths (τ ≃ 0.2–0.5 at millimeter wavelengths), despite substantial variation in disk environments — a puzzling uniformity that hints at some underlying unknown effect regulating dust physics.

We propose that this “optical depth...

9. Spirals, rings, and vortices shaped by shadows in protoplanetary disks

Alexandros Ziampras (LMU Munich)

9/22/25, 2:00 PM

Numerous protoplanetary disks exhibit shadows in scattered light observations. These shadows are typically cast by misaligned inner disks and are associated with observable structures in the outer disk such as bright arcs and spirals. Investigating the dynamics of the shadowed outer disk is therefore essential in understanding the formation and evolution of these structures. We carry out...

13. Not Your Typical Disk: ALMA unveils an expanding, ring-shaped structure in G23.6

Katharina Immer (ESO)

9/22/25, 2:15 PM

The formation of high-mass stars remains one of the key open questions in astrophysics. While structures familiar from low-mass star formation such as outflows, jets, and rotating centroids have been observed in massive star-forming regions, detailed studies at spatial scales of a few hundred AU are still rare and limited to only a handful of sources.
Recent ALMA observations of the high-mass...

4. Compact or large? CO observations of the faintest planet-forming disks.

Giulia Ricciardi (ESO)

9/22/25, 2:30 PM

Planet-forming disks observed by ALMA surveys often exhibit surprisingly faint continuum and CO emission, raising doubts about whether these disks contain enough material to account for the known exoplanet population. Despite this, the fainter end of the disk population - which shows compact, unresolved continuum emission and non-detections in CO isotopologues - has received little detailed...

6. Icy content of planet forming material with JWST

Pooneh Nazari (ESO)

9/22/25, 3:00 PM

Recent observations by ALMA suggest that planets may begin forming much earlier in the lifecycle of stellar systems than previously thought, in the protostellar systems. These systems are abundant in icy and gaseous material which can contribute to the planetesimals forming there. I will present JWST results of the icy content of these systems, particularly multiple new molecular detections...

12. Characterization of protoplanetary disks near and a far: a complementary perspective

Karina Mauco

9/22/25, 3:15 PM

Given the variety of properties found in planetary systems in our Galaxy, we must analyse general disk and host star properties measured in a large statistical sample of systems at different evolutionary stages and environments. Disks in nearby regions evolve differently than disks in highly irradiated environments. Since the majority of (exo)planet host stars (including our Solar System) form...

19. Characterising the carbon chemistry in gas giants near the snowline

Jens Kammerer (ESO)

9/22/25, 3:30 PM

Direct observations of substellar companions are ideally suited to study young giant planets and brown dwarfs during or shortly after their formation. As such, this unique class of objects provides valuable insights into planet formation processes and the imprints they leave on the chemical composition and atmospheric properties of young companions. However, the traditional population of...

2. Isotopologue chemistry imprinted on young planets

Alex Cridland (Universitäts-Sternwarte Munich (USM), LMU)

9/22/25, 3:45 PM

We have long been interested in the chemical link between protoplanetary disks and planetary atmospheres. But this has largely been limited to the most abundant isotopes of elements like oxygen and carbon. More recent observational efforts have begun to identify the precence of less abundant isotopologues like $^{13}$CO in the atmospheres of giant planets and sub-stellar objects. Here I will...

18. Is the high-energy environment of K2-18b special?

Surangkhana Rukdee (MPE)

9/22/25, 4:00 PM

The high-energy environments of host stars can shape the chemistry of exoplanet atmospheres. In nearby benchmark systems, hosting rocky to sub-Neptunian planets, we focus on the impact on biosignature gases such as oxygen, methane, and carbon dioxide. With new data from Chandra, eROSITA and XMM-Newton, we study the X-ray flux variability on timescales of days to years. Using a Bayesian...

23. Discussion

9/22/25, 4:15 PM

24. Closing Remarks

9/22/25, 4:45 PM