The Object Type in Simbad is defined as a hierarchical classification, which emphasizes the physical nature of the object. To have more details, please read the explanation page.
Each class has normally a standard designation, a condensed one (used in tables) and an extended explanation. The "hierarchy" column gives the list of types used behind selection criteria queries/TAP/Aladin.
This description of object types is presented as the following table, downloadable in text files, or viewed as graphical representations (tree, bubbles, sunburst). Please use the menu/icons just bellow.