Galaxy formation entails the hierarchical assembly of mass, along with the condensation of baryons and the ensuing, self-regulating star formation. The stars form a collisionless system whose orbit distribution retains dynamical memory that can constrain a galaxys formation history. The ordered-rotation dominated orbits with near maximum circularity $lambda_z simeq1$ and the random-motion dominated orbits with low circularity $lambda_z simeq0$ are called kinematically cold and kinematically hot, respectively. The fraction of stars on `cold orbits, compared to the fraction of stars on `hot orbits, speaks directly to the quiescence or violence of the galaxies formation histories. Here we present such orbit distributions, derived from stellar kinematic maps via orbit-based modelling for a well defined, large sample of 300 nearby galaxies. The sample, drawn from the CALIFA survey, includes the main morphological galaxy types and spans the total stellar mass range from $10^{8.7}$ to $10^{11.9}$ solar masses. Our analysis derives the orbit-circularity distribution as a function of galaxy mass, $p(lambda_z~|~M_star)$, and its volume-averaged total distribution, $p(lambda_z)$. We find that across most of the considered mass range and across morphological types, there are more stars on `warm orbits defined as $0.25le lambda_z le 0.8$ than on either `cold or `hot orbits. This orbit-based Hubble diagram provides a benchmark for galaxy formation simulations in a cosmological context.
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