Determine the effect of stellar saturation on the measured shell profile

Determine to what extent saturation of the central pixels in the SPHEREx images of VY Canis Majoris affects the measured stellar point-spread function, particularly its wings, and consequently the inferred emission in the apparent inner region of the shell.

Background

The authors measure residual emission between VY Canis Majoris and the detected outer shell using SPHEREx aperture photometry. They caution that this apparent inner-region emission may not be intrinsic to a spherical shell because the central star saturates several detector pixels, potentially distorting the empirical point-spread function used to remove the stellar contribution.

Although the authors fit the unsaturated wings with an exposure-specific empirical point-spread function and estimate the stellar peak, they state that the impact of saturation on the stellar profile—especially the wings that could mimic diffuse inner emission—cannot be reliably assessed from the available data.