Brian Tung wrote:

How is "a few tenths" either precise or non-arbitrary? That's the
problem I have with the definition. Not to say that other definitions
aren't also similarly freighted with problems; they are. And I will
go along with David so far as to say that sphericity is a promising
direction. But he seems to think it's essentially a done deal. Maybe
I've misread him in that regard, but he seems awfully confident about
the definition.

I don't see it as a "done deal" by any means, but quite frankly, it is
probably the direction that things need to go. It is certainly less
arbitrary than just setting a minimum diameter for no apparent reason.
Using a density/radius curve for a diameter "cutoff" as Stern and
Levison have done seems a logical way to decide whether an object might
be classified as a planet rather than just an asteroid. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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