The ALMA Legacy survey of Class 0/I disks in Corona australis, Aquila, chaMaeleon, oPhiuchus north, Ophiuchus, Serpens (CAMPOS). I. Evolution of Protostellar disk radii

We surveyed nearly all the embedded protostars in seven nearby clouds (Corona Australis, Aquila, Chamaeleon I & II, Ophiuchus North, Ophiuchus, Serpens) with the Atacama Large Millimeter/submillimeter Array at 1. 3mm observations with a resolution of 0. 1". This survey detected 184 protostellar disks, 90 of which were observed at a resolution of 14-18 au, making it one of the most comprehensive high-resolution disk samples across various protostellar evolutionary stages to date. Our key findings include the detection of new annular substructures in two Class I and two Flat-spectrum sources, while 21 embedded protostars exhibit distinct asymmetries or substructures in their disks. We find that protostellar disks have a substantially large variability in their radii across all classes. In particular, the fraction of large disks with sizes above 40 au decreases with the protostellar evolutionary stage. Compiling the literature data, we discovered an increasing trend of the gas disk radii to dust disk radii ratio (R ₆₀ₒ, ₊₄₏/R ₌₌) with increasing bolometric temperature (T ₁₎₋). Our results indicate that the dust and gas disk radii decouple during the early Class I stage. We find that Class 0 dust disk size resembled the gas disk size, enabling a direct comparison between models and observational data at the earliest stages of protostellar evolution. We show that the distribution of radii in the 52 Class 0 disks in our sample is in high tension with various disk formation models, indicating that protostellar disk formation remains an unsolved question.