Physical properties study of planet systems

We combine them with 4 further values gathered from literature and we then study their distribution, also as a function of various star-planet system parameters. Our data-driven work based on 120 true obliquities - the largest sample to date - strongly confirms the presence of a single cluster of aligned planets, followed by an isotropic distribution of misaligned planets with no preferred misalignment. This result is based on a uniform distribution of stellar inclinations, for which non-uniformity could have biased previous interpretations of the arrangement of true obliquities.

We confirm that Neptunians show a tentative dichotomous distribution with data available today, but its veracity needs confirmation with an enlarged sample, also because an anisotropic distribution of stellar inclination may be one of the factors hindering the real distribution. The future increase of the measured true obliquity sample over different planet types will allow better investigation of the relation between misalignment and system properties and help to depict a more comprehensive picture of the planetary evolution processes.