What characteristic is expected for emission lines in a nebula confirmed to be truly spherical?
Emission lines that are uniform across the face of the nebula without any visible central waist or pinch point.
When modeling a truly spherical nebula, the physical expectation for light emission, which arises when the fast wind ionizes the slow wind material, is a smooth, radially symmetric pattern. This smoothness implies that the brightness measurements should be consistent across the entire visible surface, lacking any localized areas where density is significantly higher or lower due to directional effects. The absence of structural features like apparent pinching, waisting, or localized brightening along a specific axis confirms the uniformity necessary for a spherical classification, contrasting sharply with the concentrated emissions seen in bipolar geometries.
