Planeta IX
Planeta IX ("planeta nonus"; linguis vernacularibus similiter) est corpus planetarium hypotheticum systematis solaris quod nonnulli physici planetarii circuire censent ultra orbitas aliorum planetarum omnium.

Notae

Bibliographia 
 Konstantin Batygin, Fred C. Adams, Michael E. Brown, Juliette C. Becker, "The Planet Nine Hypothesis" (26 Februarii 2019) apud arXiv.org pro Physics Reports
 Konstantin Batygin, Alessandro Morbidelli, "Dynamical Evolution Induced by Planet Nine" (4 Octobris 2017) apud arXiv.org pro Astronomical Journal
 Stuart Clark, "Beyond Pluto: the hunt for our solar system's new ninth planet" in The Observer (28 Iunii 2020)

Nexus externi 

Systema Solare
Astrophysica
Planetae ficticii
Res opinabiles