List of adjectivals and demonyms of astronomical bodies

The adjectival forms of the names of astronomical bodies are not always easily predictable. Attested adjectival forms of the larger bodies are listed below, along with non-obvious derivations of some smaller bodies; in some cases these are accompanied by their demonymic equivalents, which denote purported inhabitants of these bodies.

For Classical (Greco-Roman) names, the adjectival form is normally derived from the genitive case, which may differ from the nominative case used in English for the noun form. For instance, for a large portion of names ending in -s, the genitive and therefore the adjective changes the -s to a -d, -t, or -r, as in Isis–Isidian and Ceres–Cererian; occasionally an -n has been lost from the noun form, and reappears in the adjective, as in Pluto–Plutonian and Atlas–Atlantean.

Many of the more recent or more obscure names are only attested in mythological or literary contexts, rather than in specifically astronomical contexts. Forms ending in -ish or -ine, such as "Puckish", are not included below if a derivation in -an is also attested. Rare forms, or forms only attested with spellings not in keeping with the IAU-approved spelling (such as c for k), are shown in italics.

The suffix -ian is always unstressed: that is, /iən/. The related suffix -ean has traditionally been stressed, that is, /ˈiːən/; but in practice it is often pronounced as if it were -ian. This dichotomy should be familiar from the dual pronunciations of Caribbean as karr-i-BEE-ən and kə-RIB-i-ən.

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