Azimuthal brightness modulation reveals hidden dust rings in the disk of CI Tauri

Star system: CI Tauri | Distance from the Sun: 523 light years

CI Tauri is a young star surrounded by a protoplanetary disk—a rotating, flattened cloud of gas and dust from which planets are born. While these disks often contain rings and gaps that signal planet formation, narrow structures can be too small for telescopes to resolve directly. A new method has now revealed hidden, fine-scale features within the disk of CI Tauri by measuring how brightness changes at different angles.

The analysis focused on identifying patterns in the disk that are too small to be seen through conventional imaging. By extracting azimuthal brightness profiles—measurements of light intensity along circular paths at a set distance from the star—the team identified a specific signature at approximately 22 astronomical units from the star. This signature indicates the presence of dense, optically thick rings hidden within the thinner background material of the disk.

To confirm these findings, the team compared the archival observations from the Atacama Large Millimeter/submillimeter Array (ALMA) with synthetic models of inclined disks. These models suggest that the rings have properties consistent with the streaming instability, a process where small dust grains clump together to form larger planetesimals, the building blocks of planets. This confirms the technique as a powerful tool for probing the early stages of planetary systems.

Key findings
- Detection of an azimuthal brightness signature at 22 astronomical units from CI Tauri.
- Identification of unresolved, optically thick rings hidden within the protoplanetary disk.
- Successful application of a modeling method to see features below the telescope's nominal resolution limit.
- Observed ring properties align with conditions expected for early planetesimal formation via the streaming instability.

Scientific study

Azimuthal brightness modulation reveals hidden rings in CI Tau (external link)