Extrastelar

Extrastelar is a term used in astronomy and cosmology to describe phenomena or objects that exist outside of a specific star or solar system. It can refer to events or entities that are external to our own solar system, or to anything beyond the immediate gravitational influence of a star. For instance, while planets, asteroids, and comets are generally considered to be within a star's stellar system, objects or events originating from beyond that system, such as interstellar comets or supernova remnants from other stars, would be considered extrastellar.

The term is also sometimes used in a broader sense to distinguish between phenomena occurring within a star (intrastellar) and those occurring outside of it. For example, processes like nuclear fusion happen intrastellar, within the star itself, whereas the impact of stellar winds on surrounding space or the formation of nebulae from stellar material expelled into the interstellar medium are extrastellar phenomena. In the context of exoplanet research, the discovery of planets orbiting stars other than our Sun has further expanded the understanding and use of the term extrastelar, signifying anything beyond the confines of our own solar system's planetary bodies.