sidususest

Sidususest is a hypothetical metric used in astronomy and related thought experiments to quantify how closely an observed object matches an idealized star in terms of stability, distinctiveness of spectral features, and kinematic consistency. The term is not part of formal classification systems and is primarily encountered in pedagogical or speculative contexts.

Etymology: The word combines sidus, Latin for star, with a superlative-form ending to suggest “the most star-like” — though its usage remains informal.

Definition and calculation: Sidususest is a composite index calculated from normalized observational factors: photometric stability (lower magnitude variability), spectral feature clarity (higher signal-to-noise in prominent lines, larger line separation), and kinematic coherence (proper motion and radial velocity concordant with a stable, single-star model). These factors are weighted and summed to produce a dimensionless score between 0 and 1, with values near 1 indicating high star-like behavior and values near 0 indicating deviations.

Applications and limitations: Because sidususest is informal, its value lies in illustrating data quality or classification challenges rather than providing a formal, instrument-agnostic standard. It depends on data quality, instrumental calibration, and arbitrary weighting choices, and different researchers may adopt alternative factor sets.

Related concepts: The idea draws on general star classification principles and sidereal terminology; it is distinct from established metrics such as magnitudes, spectral types, or astrometric solutions, and is mainly used in hypothetical discussions or science fiction settings.