ALMA resolves hidden rings in compact planet-forming disks
Sharper observations of 11 compact disks in the Lupus star-forming region revealed clear inner structures in four systems and tentative features in three more. The single study used ALMA to examine scales close to young stars. Rings and gaps could help locate trapped dust, but the observations do not directly identify planets and can miss features below their resolution.
Science··Midday
Sharper views reveal structures close to young stars
Astronomers studied 11 compact disks around young stars in Lupus, a region of star formation, and detected clear inner structures in four and tentative features in three more. The single study uses observations from ALMA, the Atacama Large Millimeter/submillimeter Array in Chile. The paper has undergone peer review in Astrophysical Journal Letters; the available full text is the authors’ version. Its observations probe dust close to young stars, where earlier images had left these small disks poorly resolved.[1]
One disk has a cavity within the inner planetary region
ALMA observations reached a resolution corresponding to roughly two astronomical units, each unit being the average Earth–Sun distance. Rings, gaps and cavities appeared within ten astronomical units of the stars. In the Sz 112 disk, a central cavity extended to a radius of approximately 1.6 astronomical units. Two other disks also showed faint outer rings beyond their bright inner dust concentrations. The team checked reconstructed images against the interferometer’s visibility measurements.[1]
The rings do not directly identify planets
The lower detection rate in small disks can reflect limited resolution and dust emission that hides brightness differences. Faint outer material can also be missed. Models estimated the masses of hypothetical planets that could open gaps, but the observations did not directly image those planets. The measurements were made at a single wavelength, leaving other possible explanations for the structures. The three tentative detections remained separate from the secure findings.[1]
