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This study analyzed 30 protoplanetary disks at multiple wavelengths to track how dust evolves across three developmental stages spanning 0.5 to 6 million years. The researchers found that dust disk size remains relatively constant over time while dust mass decreases significantly, and that many disks show optically thick emission suggesting higher dust concentrations than previously thought. The multi-wavelength approach revealed gas-to-dust mass ratios much lower than earlier single-wavelength studies reported, though substantial uncertainties remain due to opacity assumptions.
Why it matters
These findings challenge existing models of planet formation by suggesting different ratios of gas to dust in young planetary systems than previously believed. Understanding how solid materials evolve in protoplanetary disks is fundamental to explaining how rocky planets like Earth and the cores of gas giants form.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract: Understanding the evolution of solids in protoplanetary discs is important to comprehend the formation of giant planets cores and terrestrial planets. The ALMA Large Program AGE-PRO studied key disc properties in a survey of 30 protoplanetary discs across three evolutionary stages: the embedded phase (0.5-1 Myr), the middle-age phase (1-3 Myr), and the end of the disc lifetime (2-6 Myr). Preliminary dust properties were estimated using 1.3 mm observations, but a multi-wavelength analysis provides a better constraint of important properties such as the dust disc mass, the dust temperature, and the maximum grain size. We present new ALMA 3.1 mm and 1.5 mm (Bands 3 and 5) continuum observations of the complete survey of 30 AGE-PRO discs. We fitted the observed visibilities and derived radial brightness profiles, spatially resolving 20 discs from the AGE-PRO sample at the two studied wavelengths. A multi-wavelength modelling was performed including also the radial profiles from the 1.3 mm observations. Our results replicate trends obtained from the single wavelength analysis: the dust disc size seems to be constant over age and the dust disc mass decreases with time, with a factor $sim$10-40 uncertainty from opacity assumptions. This result implies much lower gas-to-dust mass ratios for the discs in our sample than previously reported. In addition, the derived spectral indices are consistent with optically thick emission in a large fraction of the AGE-PRO discs, in particular for the Ophiuchus and Lupus discs.