Survey of Orion Disks with ALMA (SODA) II. UV-driven disk mass loss in L1641 and L1647

Context. External far-ultraviolet (FUV) irradiation of protoplanetary disks has an important impact on their evolution and ability to form planets. However, nearby (<300 pc) star-forming regions lack su fficiently massive young stars, while the Trapezium cluster and NGC2024 have complicated star-formation histories and their O-type stars' intense radiation fields (>10(4) G(0)) destroy disks too quickly to study this process in detail. Aims. We study disk mass loss driven by intermediate (10-1000G(0)) FUV radiation fields in L1641 and L1647, where it is driven by more common A0- and B-type stars. Methods. Using the large (N = 873) sample size o ffered by the Survey of Orion Disks with ALMA (SODA), we searched for trends in the median disk dust mass with FUV field strength across the region as a whole and in two separate regions containing a large number of irradiated disks. Results. For radiation fields between 1-100G(0), the median disk mass in the most irradiated disks drops by a factor similar to 2 over the lifetime of the region, while the 95th percentile of disk masses drops by a factor 4 over this range. This e ffect is present in multiple populations of stars, and localized in space, to within 2 pc of ionizing stars. We fitted an empirical irradiation - disk mass relation for the first time: M-dust;median = 1:3(-0:13)(+0:14) log(10)(F-FUV/G0) + 5:2(-0:19)(+0:18) . Conclusions. This work demonstrates that even intermediate FUV radiation fields have a significant impact on the evolution of protoplanetary disks.