Abstract

One of the main unsolved problems in planet formation is pinpointing the starting time for planet formation. A crucial aspect of this quest involves identifying substructures within circumstellar disks, which could serve as early indicators of planet formation. The high angular resolution observations by ALMA have been a game-changer in the field and revealed for the first-time substructures in disks with unprecedented details (eg. surveys like DSHARP & ODISEA). However, these surveys focused on more evolved Class II disks and ODISEA is limited to the Ophiuchus molecular clouds only. We present the CAMPOS Legacy survey, an ALMA survey of all embedded Class 0/I and Flat protostellar disks in the star-forming clouds of Chamaeleon, Ophiuchus, Aquila, Corona Australis, and Serpens. By probing over 90 disks down to 15 au resolution, we conducted the first statistical search for disk substructures around Class 0/I protostars. Our findings reveal compelling evidence suggesting a lack of substructures in young Class 0 and early Class I disks. Intriguingly, disk substructures begin to emerge only in sources with a bolometric temperature exceeding 160 K, indicating the rapid evolution of disk substructures during the Class I phase. Our CAMPOS survey has for the first time discovered how early disk substructures form and, as a corollary, when giant planet formation begins.