ProgSun

ProgSun is a hypothetical concept within theoretical astrophysics, referring to a star that exhibits characteristics of both a pre-main-sequence star and a sun-like main-sequence star. This designation is not a formally recognized astronomical classification but rather a term used in discussions or thought experiments concerning stellar evolution. The idea of a progSun might arise when considering the transitional phases a star undergoes as it moves from its protostellar cloud stage towards achieving stable hydrogen fusion. During this phase, a star's luminosity and temperature are still fluctuating significantly, making it distinct from a fully established main-sequence star.

The concept of a progSun could also be explored in scenarios where a star's internal processes are undergoing unusual changes, leading to temporary deviations from its expected evolutionary track. For instance, a star nearing the end of its main-sequence life might exhibit properties that superficially resemble an earlier evolutionary stage. However, in standard astrophysical models, such transient states are usually described with more specific terminology related to later evolutionary phases like the subgiant or red giant branches, rather than a novel "progSun" classification. The term remains largely speculative and serves as a conceptual tool rather than an observational category.