Wednesday, June 11, 2008

IAU decides to call Pluto and Eris "plutoids"

Almost two years after the new class of dwarf planets was introduced in the solar system, with Pluto, Eris and Ceres as the first members, another directive from the 2006 General Assembly in Prague has now been fulfilled: the subclass of dwarf planets residing in the Kuiper belt has been named "plutoids". Furthermore it was decided that any Solar System body having a semimajor axis greater than that of Neptune and an absolute magnitude brighter than H=+1 mag. will be considered to be a plutoid (which has implications for the formalities by which it will be given a proper name). The IAU did not announce any new entries into the dwarf planet/plutoid class or when that will happen - but it should be only a matter of time until 2003 EL61 and 2005 FY9 are accepted; see this inofficial list once compiled by this blogger.

In other news this blog has just learned about successful imaging of Venus 3.7 arc minutes(!!!) from the solar limb yesterday morning: The photographer masked part of his DSLR's chip with a metal strip, used a neutral density filter and Herschel wedge with his refractor telescope (to keep the heat away from the electronics) and made long exposures ... • Amateur astronomers played a role in triggering crucial radio observations of dwarf nova SS Cyg. • There is now a new sunspot group which has since been given the number (10)998. • Jupiter with an 8" telescope and at low elevation from Germany - still pictures like these were possible last night, or methane observations; here is a collection. • Another Namibian astronomy expedition report. • And selected sky pictures from above.

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