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Cheap Astronomy
2008-Nov-09, 07:49 AM
Does anyone have more details on Haumea (http://en.wikipedia.org/wiki/(136108)_2003_EL61) - specifically, although clearly not spherical, it gets a guernsey as a dwarf planet before other rounder candidates.

The Wikipedia article notes:
Nonetheless, its gravity is believed sufficient for it to have relaxed into hydrostatic equilibrium, thereby meeting the definition of a dwarf planet.

Hopefully there more to this than just belief. From the way things are going we might as well just say anything that's bigger than Ceres is a dwarf planet. Surely the whole point of the 'second law' of planets is that it's not just about size.

01101001
2008-Nov-09, 06:43 PM
Does anyone have more details on Haumea (http://en.wikipedia.org/wiki/(136108)_2003_EL61)

There's always the discoverer's site: Caltech :: Mike Brown :: Haumea (http://www.gps.caltech.edu/~mbrown/2003EL61/)

Are you just looking for more reading matter? The Web didn't provide enough?

Keywords: Haumea, 2003 EL61

Your closing statements: did you mean them to be questions?

Gigabyte
2008-Nov-09, 07:30 PM
The IAU definition is certainly a bone of contention.

Cheap Astronomy
2008-Nov-13, 09:11 AM
Thanks. I suppose there wasn't really a question there - more a hypothesis waiting to be debunked.

I don't think Haumea is a good fit with the 3 laws of planets, with little evidence to indicate it is (or ever was) in hydrostatic equilibrium. I think a routine has been established of just applying the term to known celestial bodies in descending order of diameter - which will keep being applied to anything bigger than Ceres.

grant hutchison
2008-Nov-13, 11:41 AM
I don't think Haumea is a good fit with the 3 laws of planets, with little evidence to indicate it is (or ever was) in hydrostatic equilibrium.Well, the best-fit ellipsoid for the light curve is in hydrostatic equilibrium if reasonable assumptions are made about density. And for it not to be in hydrostatic equilibrium would require unreasonable assumptions about rigidity. So it doesn't seem like a particularly bad call, on the weight of evidence.

Grant Hutchison