I don’t need to remind you about the Pluto reclassification episode of a while back, I’m sure. See posts here, here, and here otherwise.
(Right: Mathias Pedersen‘s “Poor Pluto” poster, used with permission. Discussed here previously.)
The International Astronomical Union (IAU) felt the need to reclassify Pluto in the light of ongoing scientific discovery – it’s just one of probably thousands of small objects out there beyond the orbit of Neptune. This area of science is very much alive- we’re learning a lot about the solar system and other planetary systems. (See my post entitled “Clues in the Blood Splatter Patterns”.) The “demotion” led to lots of angry opinion, you may recall.
Well, the IAU’s Committee on Small Body Nomenclature (I love that!) has now decided that Pluto is the prototype of a new class of objects – Plutoids.
They said in their press release (among other things):
Plutoids are celestial bodies in orbit around the Sun at a distance greater than that of Neptune that have sufficient mass for their self-gravity to overcome rigid body forces so that they assume a hydrostatic equilibrium (near-spherical) shape, and that have not cleared the neighbourhood around their orbit. Satellites of plutoids are not plutoids themselves, even if they are massive enough that their shape is dictated by self-gravity. The two known and named plutoids are Pluto and Eris. It is expected that more plutoids will be named as science progresses and new discoveries are made.
The dwarf planet Ceres is not a plutoid as it is located in the asteroid belt between Mars and Jupiter. Current scientific knowledge lends credence to the belief that Ceres is the only object of its kind. Therefore, a separate category of Ceres-like dwarf planets will not be proposed at this time.
There are news articles in several places, such as at Space and at the BBC.
-cvj
(Thanks Oliver, Shelley…)
