M512 ALMA B3 and B6 images

These structures replenish disks with fresh material, have the potential to significantly alter their dynamics, trigger the formation of substructures, induce shocks, and modify their physical and chemical properties. In this study, we combine new ALMA band 3 and archival band 6 observations to characterize the dust content and mass infall rate of a 4000au arc-like structure infalling onto M512, a class I young stellar object located in the Lynds 1641 region of the Orion A molecular cloud.

We measure for the first time spectral index maps and derive a dust opacity index profile along a streamer, constraining grain properties and its dust mass. We measure a spectral index {alpha}~3.2 across the entire structure, and a dust opacity index {beta}~1.6. Given grain properties consistent with the measured {beta}, the structure can host up to 245M_{Earth}_ of dust, being comparable or even exceeding the mass of the inner, unresolved 600au, which contains the protoplanetary disk of M512.