An Application Note: Registrability-Based Structural Classification of the VY Canis Majoris Dimming Event

VY Canis Majoris (VY CMa) is a red hypergiant exhibiting extreme, long-duration optical suppression alongside persistent infrared and sub-millimetre emission arising from a complex, asymmetric circumstellar environment. Such behavior has frequently prompted interpretive escalation toward rapid stellar evolution, envelope instability, or imminent supernova scenarios. However, dramatic optical variability alone does not constitute evidence of intrinsic structural collapse. In this application note, we apply a registrability-based structural classification framework to VY CMa without introducing assumptions regarding stellar evolutionary transition. The framework enforces ordered evaluation of duration, chromatic behavior, multi-channel persistence, geometric admissibility, stability constraints, recurrence, and identity recoverability prior to interpretive inference. We demonstrate that VY CMa is naturally classified as a Class IV identity-preserved, dust-dominated registrability system. The observed optical suppression is shown to arise from evolving circumstellar boundary structure and radiative reprocessing rather than from intrinsic luminosity loss or envelope destruction. Bolometric output remains broadly consistent across epochs, and red hypergiant spectral features re-emerge when observational geometry permits. This case illustrates the importance of registrability-first classification as a conservative, scalable diagnostic for apparent stellar disappearance events, particularly for mass-losing supergiants and hypergiants embedded within extended dust-rich environments.