Topic: Small Companion to Brown Dwarf Challenges Simple Definition

[sam]

As our telescopes grow more powerful, astronomers are uncovering objects that defy conventional wisdom. This latest example is the discovery of a planet-like object circling a brown dwarf. It's the right size for a planet, estimated to be 5-10 times the mass of Jupiter. There has been a lot of discussion in the context of the Pluto debate over how small an object can be and still be called a planet. This new observation addresses the question at the other end of the size spectrum: How small can an object be and still be a brown dwarf rather than a planet? This new companion is within the range of masses observed for planets around stars — less than 15 Jupiter masses. But should it be called a planet? The answer is strongly connected to the mechanism by which the companion most likely formed. What's even more puzzling is that the object formed in just 1 million years, a very short time to make a planet according to conventional theory.

http://hubblesite.org/newscenter/archive/releases/2010/03/

Very interesting stuff! I think a planet would make sense in a mass arguement but hard to go with that given its not a star... hmmm. Semantics really.

[Clive]

This debate will go on for a long time yet.  Just like the one betweeen comets and asteroids.

[sam]

indeed... maybe I should write another article..

[Clive]