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 sufficiently massive young stars, while the Trapezium cluster and NGC 2024 have complicated star-formation histories and their O-type stars'intense radiation fields (> 104G0) destroy disks too quickly to study this process in detail. Aims. We study disk mass loss driven by intermediate (10-1000G0) 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 offered 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 1-100G0, the median disk mass in the most irradiated disks drops by a factor ~2 over the lifetime of the region, while the 95th percentile of disk masses drops by a factor 4 over this range. This effect 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: Mdust,median = -1.3-0.13+0.14 log10(FFUV/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.