Refining the Migrating Differentiated Planetesimal Disruption Model for Classical T-Tauri Star RW Aur A’s Dimming Events

Abstract C. M. Lisse et al. (2022) published a near-infrared time domain spectral study of the dimming events in RW Aurigae A (RWAurA). Emission from the protostellar surface, protostellar atmosphere, accretion disk, and jets was reported, with the most pronounced changes seen in jet emission amplitude due to siderophilic elements. RWAurA also evinced a strong increase in protostellar atmosphere emission due to accretion by lithophilic elements. This segregation of emission features was noted to match the evaporation susceptibility of a differentiated planetesimal’s core versus the thermal stability of rocky mantle solids in the environment of the inner accretion disk wall region, and a fortuitous planetesimal collisional disruption was hypothesized. Here we refine this event as the consequence of the tidal disruption of an inwardly migrating differentiated planetesimal containing a molten core, and call for re-monitoring of the system in the light of H i :Fe ii :Ni ii :S ii :N i :He i during the new major dimming event that started in early 2025.