A Ninth Planet?


Researchers have found indirect evidence of a ninth planet belonging to the solar system. Gravitional interactions in the Kuiper belt indicate the presence of a Neptune-sized body, located far away from the Sun. Currently based on mathematical simulations the planet can only be acknowledged if corroborated by direct observations.



In January 2016 astronomers Konstantin Batygin and Michael E. Brown reported that they have found strong evidence for a ninth major planet. Their findings were based on a detailed study of some of the known dwarf planets orbiting the Sun in distant and strongly eccentric orbits. Six of them had their perihelium points quite close to each other (see figure to the right), a very unprobable configuration unless an unknown large mass affected them by gravitational resonance.

Through extensive simulations their conclusion is that a planet with a mass of about 10 Earth masses and the  following properties would best fit the available data:

  • aphelion ~1200 AU, perihelion ~200 AU
  • eccentricity e ~0.6,
  • orbital period 10,000 to 20,000 years,
  • an inclination  ~30° to the ecliptic

The planet needs to be identified visually in order to confirm its existence. Its magnitude could be about V=22, which makes it difficult but possible to detect with large telescopes. Howeverm, since its position on the sky is largely unknown, this undertaking is quite formidable.


More information:

Planet Nine (Wikipedia)

Evidence For a Distant Giant Planet in the Solar System (Batygin & Brown)



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