Tuesday, July 15, 2008

2005 FY9 becomes 4th dwarf planet, named Makemake

The official list of dwarf planets now has four entries: Kuiperoid 2005 FY9 alias (136472) alias Makemake - see here for pronounciation issues with this Polynesian word - joins Ceres, Pluto and Eris and is also the 3rd official plutoid. Its naming decision seems to have been relatively uncontroversial while the third big Kuiperoid announced in 2005 still has to wait because there's a lingering question of priority over 2003 EL61. Which is also not exactly spherical but shaped like a football due to its fast rotation, a fact that might even threaten its future classification as a dwarf planet, despite its size. (This incidentally calls into question the "hydrostatic equilibrium" demand as a key criterion for both planets and dwarf planets: Even beyond a diameter of 1000 km a body can still be very un-spherical.)

In other news NASA's Wayne Hale recalls a solar flare scare on the ISS in 2006. • There is a new candidate for the brightest star in the Galaxy. • And to look at: a movie clip of 2008 BT18 near Earth, heavy image processing of comet Boattini, apparently revealing a dust tail next to the ion tail, and hi-res images of the ISS from 14 July and 13 July showing well the new Columbus and Kibo modules.

1 comment:

Laurel Kornfeld said...

You seem to love the word "Kuiperoid." Did you make that word up? Is that the reason you keep repeating it? Why isn't the IAU using it?

These dwarf planets are planets. This pretense that the controversy regarding planet definition is over does not make it so. Hydrostatic equilibrium is still the best measure for defining an object because objects in hydrostatic equilibrium are fundamentally different than those that are not. The former have geophysical and geological processes while the latter are inert objects. It is very likely that Dawn and New Horizons will reveal that both Ceres and Pluto have these processes. The other large KBOs in hydrostatic equilibrium may very well have them too. Whether 2003EL61 has such processes should be the ultimate determinant of its classification.