Odd Planet Confuses Scientists

eldavojohn writes "While there's been a lot of debate about what is a planet, there is a recent discovery that has scientists even more confused. COROT (COnvection ROtation and planetary Transits) spotted an object that appears to be the size of Jupiter yet is 21.6 times more massive ... and orbits its star in a mere four days and six hours. Now, the other piece of the puzzle is that the star it orbits is more massive and only slightly larger than our Sun. But they can't describe this thing orbiting it. So far they think it is more likely to be a 'failed star' but have settled with 'member of a new-found family of very massive planets that encircle stars more massive than the sun' to describe it accurately."

Comments

Bad Data

[SpaceMika]

This was followed up on the astro mailing lists as faulty data -- the observers mistook sunspot-dimming for a planet passing in front of the star. The correction hasn't made it to journalists yet and the science article is still in draft, so no link-to-reference, sorry! Planetary formation theory is fragmented and deeply in need of reworking (anyone want a phd topic?), but not to incorporate Jupiters in Mercury-orbits (yet).

Hold on a minute here...

[MarkusQ]

The density of Jupiter is about 4/3, so 21 times that would put it at 28 and change. That means it would have to be significantly denser than Iridium (about 22). That means it would have to be either:

• An enormous lump of some element with a very short half life
• Something from some island of stability
• An ultra-compact degenerate form of normal matter (iron nickel compote)
• A data error

Guess where I'd put my money...

--MarkusQ

Re:What's it made of?

[MozeeToby]

Metallic Hydrogen? Though you would think that it would begin to fuse at that kind of mass-density. Then again, 26 times the mass of Jupiter is still less than 3% the mass of the sun so perhaps not. My guess is that this is the edge case. If there were even a little more mass it would have collapsed into a red dwarf and started fusing hydrogen.

Re:Is orbital mechanics fractal?

[mcrbids]

Does orbital mechanics lead to fractal planetary arrangements?

Good, question, but my "shooting at the hip" answer is that while there may be some tendencies toward that kind of arrangement, that applies to certain conditions that are limited. Roughly, around our star, each planet ~2x the distance as the previous, out to Neptune or so.

I'd guess that while it happened here, that it won't happen everywhere, or that there's only a tendency toward this.

I think the idea of trying to define a planet vs asteroid vs planetoid vs failed star is kind of like trying to define the difference between a pebble", a rock, a stone, and a boulder. When does a pebble become a rock? When does a rock become a stone, and when does a stone become a boulder?

There's no clear line, and there doesn't need to be. Seriously: why do we care?