ALMA Observations Reveal a Young Protoplanetary Disk with Complex Structure
The ALMA radio telescope array has captured unprecedented details in disks surrounding young Class I stars. By processing archival data with the PRIISM technique in Band 6, the disk of the source CrA IRS 2, located in the Corona Australis molecular cloud, was observed with great clarity. 🪐
A Detailed Portrait of Stellar Dust
The obtained dust continuum image has a spatial resolution 50% better than that achieved by conventional methods. For the first time, such a young system is seen exhibiting both a central inner cavity and rings with gaps in its outermost part. This positions CrA IRS 2, with a bolometric temperature of 235 K, as the most primitive object known with these characteristics. The wide gas ring surrounding it could form due to advection of magnetic flux.
Key characteristics of the observed system:- Multiple substructures are detected, including a central cavity and rings.
- The achieved resolution is 0.1 arcseconds, thanks to ALMA.
- The system temperature is only 235 K, indicating a very early phase.
The early formation of a giant planet could be facilitated by the dissipation of magnetic flux, which suppresses turbulence and extends the disk's dead zone.
The Imprint of a Possible Forming Planet
To understand the origin of the outer rings and gaps, the data were compared with planet-disk interaction models. The depth and width measurements match these models, pointing to the possible presence of a giant planet. Its mass is estimated between 0.1 and 1.8 times that of Jupiter.
Factors that could enable such rapid planet formation:- Dissipation of magnetic flux slows down turbulence generated by magnetorotational instability.
- By expanding the disk's dead zone, dust particles can grow more effectively.
- This environment favors material accumulation and the start of planetary core formation.
Rewriting the Early Stages of a Solar System
While other disks in this phase are just beginning to organize their material, CrA IRS 2 appears to already be actively sculpting its future planetary system. These findings suggest that processes to form planets can begin and progress much earlier than previously thought, challenging some established models. 🔭