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

Is orbital mechanics fractal?

[Ungrounded Lightning]

One thing I've wondered about: Does orbital mechanics lead to fractal planetary arrangements?

If so, binary stars and star/gas-giant planetary systems are just points in a continuum.

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?

Re:Is orbital mechanics fractal?

[Artifakt]

A usual property of fractal dimensions is they aren't integers. Cases with interger dimensionality in articles and books on fractals are simplified or 'degenerate' fractals. If scientists found themselves relying on math that involved non-integral dimensions to describe planetary systems, I could definitely see there being 'fractal planetary arrangements', but baring that, similarities across scales aren't enough to throw around a word such as fractals.
      The idea sounds like an extension of Bode's law, by people who are trying to modernize the old model. The original Bode's law may have been a case of people seeing patterns that aren't really there in reality at all, simply an overfunctioning of the brain's pattern detecting apparatus. Knowing there's a temptation to interpret the data this way, I'd be cautious trying to stretch fractal math to fit unless all of it fits.

What's it made of?

[Canadian_Daemon]

If it is twice as dense as lead, what is it made of?

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:What's it made of?

[antirelic]

I wonder if this is just a result of some weird gravitational lensing effect? I'm not very familiar with the technique, but from what I understand, its kind of like looking at a shadow in order to try and figure out the shape of an object... except the light source is light years away and the object is equally far away.... I'm sure as time goes by and our observation techniques improve, we are going to see many different things that we never thought would be possible. Yes yes... physics is physics, but humanity has a problem with adjusting to scales, and space is a very, very big thing.

There is little way to control the environments in order to do controlled experiments, all we have are observations... which at such great distances, must be very susceptible to nearly infinite sources of interference that we simply cannot identify with present means.

With that said... a new category of planets off of one object? Getting carried away much...?

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:Hold on a minute here...

[MarkusQ]

Now, take something the size of Jupiter, put it close enough to orbit every 4 days, and ask yourself: could that maybe be an environment where gas laws might become significant?

Admittedly I'm just eyeballing it, but I can't see how you can make that work. Remember the T part of P=T/V works against you here; the higher temperature should make it less dense, which both reduces the gravitational forces on the outer portions (larger r) and increases their area and thus the amount of energy those on the sunward side absorb. Sure, you could equilibrate by spinning it fast, but that makes things worse in a different way.

I can see how you could get the core density up that high, but not the total density. Remember, the sun, for all it's size and mass, is only a few percent more dense than Jupiter.

--MarkusQ

Re:Hold on a minute here...

[w0mprat]

Jupiter has density of 1.326 gcm. So thats 28.6416 for this object. Just to be pedantic.

This kind of density boggles the mind. What could have this density? Tungsten, Platninum? Osmium is not getting close.

Considering the mind boggling surface gravity of a object like this, we don't know how many materials behave under incredible pressure, for example the centre core of the earth, while largely iron, is more like crystal. The core of jupiter might be shrouded in metallic hydrogen. Indeed we understand very little about such conditions. Density could be largely due to immense compression of materials that would be otherwise less dense?

Realisticly this will just turn out be a core of a hypermetallic brown dwarf or something that has had it's outer layers stripped.