Ring warsa 2006, Persatuan Astronomi Internasional (IAU) nyobyahang artos planét sané sayukti.[1] Pluto nénten manut sareng artos saking planét punika, nika mawinan Pluto kagingsirang ka golongan Planét Katai.
But then the International Astronomical Union (IAU) defined the term "planet" formally in 2006 and Pluto didn't fit the definition.