umlaufender

Umlaufender is a German present participle derived from the verb umlaufen, meaning to go around or orbit. In practice it functions as an attributive adjective describing something that is in an orbit or circulating around another body. The term is most common in scientific and technical contexts, especially in astronomy and celestial mechanics, where it describes objects that move along an orbital path.

In usage, umlaufender can govern different noun classes and cases. Examples include: der umlaufende Planet (the orbiting planet), ein umlaufender Körper (an orbiting body), or umlaufende Körper (orbiting bodies) in plural form. When used with a definite article, the adjective takes the weak ending: der umlaufende Planet; with an indefinite article, the ending reflects mixed declension: ein umlaufender Planet. Without articles, the plural form is umlaufende Planeten.

Predicative usage of the participle is less common in everyday language; more typical is to describe the motion with a verb, as in der Planet kreist um die Sonne. Nevertheless, umlaufend or umlaufender can appear in technical prose to compressively characterize a subject as orbital.

Related terms include Umlaufbahn (orbital path or orbit), Umlaufzeit (orbital period), and Umlaufkleinheiten in some contexts. The concept underpins descriptions of planets, moons, satellites, and other bodies bound in orbital motion around a primary object. While mainly used in scientific writing, umlaufender also appears in dictionaries and encyclopedic texts to convey the notion of being in an orbit.