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Space Science

Odd Planet Confuses Scientists 142

Posted by samzenpus
from the that's-no-moon dept.
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."
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Odd Planet Confuses Scientists

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  • by Daswolfen (1277224) on Wednesday October 08, 2008 @07:57PM (#25307423)

    ... but that's no moon.

  • by Ungrounded Lightning (62228) on Wednesday October 08, 2008 @08:05PM (#25307479) Journal

    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.

    • Maybe it's been too long since I've studied fractals and astronomy, but I have no idea what a "fractal planetary arrangement" is, nor can I even guess.
      • Well thanks for posting your nugget of wisdom :P
        • No, thank you for not adding anything to the discussion. If you can explain what was meant, please do. If not, please don't bother posting.

          But seriously, a continuum of what? What the hell does fractal geometry apply to planetary arrangements? To me those two sentences are nonsense. As I see it, fractals just don't apply. It's like asking if we'll have a long winter because a groundhog sees its shadow.

          If I'm wrong, please enlighten me. That was the hope of my original post.

      • ... I have no idea what a "fractal planetary arrangement" is...

        The aspect of "fractal" I had in mind was "equivalently arranged across large variations in scale".

        I.e. a gas giant and its moons are just a small version of a star and its planets, etc.

        Of course you do get a discontinuity between a star that ignites and a gas giant that does not. For instance: A star's heat drives more volatiles off the orbiting rocky objects than a gas giant's warmth does. Solar wind tends to clear out small debris. (And t

        • by Artifakt (700173) on Wednesday October 08, 2008 @11:08PM (#25308839)

          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.

          • by Prune (557140)
            Writing "integer dimensionality" is grammatically incorrect; you should have written "integral dimensionality" because "integer" is always a noun.
          • 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.

            Like this [wikipedia.org]?

      • by mikael (484)

        I think he meant orbital ratios.

        In a solar system, the planets around a star (or moons around a planet) need to have orbits that have the same ratio otherwise the accumulated grativational forces would throw one or more objects out of the system.

        This article [hypography.com] has a good explanation.

    • by carambola5 (456983) on Wednesday October 08, 2008 @09:23PM (#25308121) Homepage

      My bet is that they just misplaced a decimal point somewhere. It's always some mundane detail like that.

      • by jd (1658)
        Or got the units wrong. The measurements weren't taken by the guys who designed all those Mars landers that crashed, were they?
    • Oh yea, me too. I wonder about that all the time. Farctal planet arranging and gassy star giants and stuff, yea.
    • by mcrbids (148650) on Wednesday October 08, 2008 @10:53PM (#25308733) Journal

      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?

      • by Mukaikubo (724906)
        Actually, in the solar system gaps between planets range from 1.4 to just under 2, if you count the failed planet where the asteroid belt is (probably got shredded by Jupiter's gravitational influence while it was trying to form). This tends to happen because 1.4 or so is roughly the region of stability for coplanar elliptical near-circular orbits; any closer and the third body perturbation significantly messes around with the orbit over a long time scale. Lunar systems of gas giants are also governed by o
      • Re: (Score:3, Funny)

        by Zeromous (668365)

        I don't get it. Can you please re-frame your example using a car analogy?

  • by MRe_nl (306212) on Wednesday October 08, 2008 @08:14PM (#25307535)

    "the size of Jupiter yet 21.6 times more massive.. and orbits its star in a mere four days and six hours."

    That's New Year roughly twice a week, by Jove.
    Party on ; ).

  • ...before long astrophysicists will have more words for things that orbit other things than the Inuit have for snow.

    • Re: (Score:1, Funny)

      by Anonymous Coward

      I don't think the Inuit has more words for snow than we do in English:
      Water, ice, black ice, snow, rain, slush, wet snow, dry snow, powder snow, pellet snow, feather snow...

      • Re: (Score:3, Informative)

        by Opyros (1153335)
        Several of those are phrases, not individual words. However, Inuit languages don't really have a large number of independent words for snow, either; their polysynthetic structure makes it possible to form an unlimited number of words relating to snow from a handful of elements. This article [upenn.edu] by the linguist Geoffrey K. Pullum has more details.
  • What's it made of? (Score:3, Interesting)

    by Canadian_Daemon (642176) on Wednesday October 08, 2008 @08:16PM (#25307551)
    If it is twice as dense as lead, what is it made of?
    • by MozeeToby (1163751) on Wednesday October 08, 2008 @08:32PM (#25307695)

      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.

      • Don't think so (Score:5, Informative)

        by Moraelin (679338) on Thursday October 09, 2008 @12:48AM (#25309461) Journal

        Actually, I don't think that metallic hydrogen is twice as dense as solid lead.

        If you look at most metals, the higher the atomic weight, the higher the density of the solid. Depleted uranium is heavy, while Aluminium is lightweight, and Lithium is half the density of water, for example. So for hydrogen, metallic or not, to be denser than lead, you need it to be packed tighter than, I think, is physically possible.

        At some quick maths, a hydrogen atom is 1, lead is 207-208 (82 protons and a load of neutrons.) I know that some mass is actually in the binding energy between those, but for some quick and very approximative maths let's say a lead atom is 200 times heavier than a hydrogen one. (Plus/minus something.) At the same distance between atoms, lead will be 200 times heavier than hydrogen. To go for twice as heavy, you need the hydrogen atoms to be packed at over 7 times less distance from each other than lead atoms are.

        At a quick googling, the estimated range of densities for metallic hydrogen is anywhere between 0.4g per cubic centimetre (less than lithium) and 4g per cc (4 times as heavy as water), with apparently 0.8 being the most likely candidate for where it turns metal. Compress it any denser and it'll start to fuse. And we're still nowhere near as heavy as we need for that planet.

        What throws a further spanner into it, is that our own gas giants _already_ have a core of metallic hydrogen. That' what's in the middle of Jupiter and Saturn. So something 26 times heavier, hmm, must be something else.

        • by shpoffo (114124)

          "A polar bear is a cartesian bear after a coordinate transform."

          Perhaps then polar bears are now converting back to cartesian bears with the Global Thermal coordinate transform

    • Re: (Score:3, Funny)

      by c_forq (924234)
      Really dense lead?
    • by antirelic (1030688) on Wednesday October 08, 2008 @08:46PM (#25307807) Journal

      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...?

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

        Well, they only have two options. They can redefine an existing, well-defined and -populated category to also encompass this one mysterious planet, or they can (perhaps temporarily, pending further observations) give it its own new category. You really the the latter is more drastic?

        • They can't really make up their minds about what a planet is anyways, so why bother. My guess they could add sub-cathegories to the Planet cathegory. If they have one for stars, why not for planets?
      • Re: (Score:3, Insightful)

        by Fluffeh (1273756)
        No, gravitational lensing would not change the observations. Gravitation lensing works by bending light through the sheer force of gravity of supermassive objects. Be this slight bend, the light waves are expanded (thereby making them appear closer). If would not however change the size of the star visible, the heat signature it gives off, the wobble caused by the planet or how quickly the planet orbits the sun.

        Apart from no-one understanding what formed this planet and why it is so dense, I don't see ho
      • Repeating an old joke:

        An astronomer, a physicist and a mathematician are traveling on a train through Scotland. Through the window of the train they notice a black sheep.

        "Aha," says the astronomer. "In Scotland, all sheep are black."

        "Hm...," says the physicist, "I believe you mean that some sheep in Scotland are black."

        "No, no," says the mathematician. "You are both wrong. All we know is that there is at least one sheep in Scotland, and at least one side of this sheep is black".
    • A big blob of dark matter wrapped in something nice and baryonic?

      • Ironically, I just realized I was also describing the contents of my toilet bowl shortly after I woke up this morning...

    • by hatchet (528688)
      Because of very high pressure, the atoms would start losing electrons which will allow them to be packed much denser. This is called electron degeneracy. This also happens in white dwarfs, which is what our sun will become one day.
  • MOANFFOVMPTESMMTTS is not really the best acronym for anyone. Did they blow their acronymic wad with WIMPs and MACHOs and RAMBOs and whatnot?
  • Everyone might want to remember that they cannot "see" any of these alleged planets they keep coming up with. Gee, I wonder why they can't explain their findings!
    • Maybe they don't "see" them with the naked eye, but they observe wobbles in the position of a star or observe when the planet occludes the star. How is that so far removed from when you look at any other picture? All you're really seeing is light reflected off the developed photograph. You're not "seeing" the light that hit the negative, but rather you're getting light that is a few steps removed conceptually from the original photons. Does that mean there's no evidence that what's in the picture actual

      • Detecting Exoplanets (Score:5, Informative)

        by SpaceMika (867804) on Wednesday October 08, 2008 @10:29PM (#25308553)
        There are two ways of detecting exoplanets:
        1. Wobbles -- what you explained: watch a star for deviations in its orbit by observing tiny redshifts and blueshifts. Our own sun does a little jiggle thanks mostly to Jupiter.
        2. Dimness -- what they did for this object. Watch a star for dimming as something passes in front of it, although you have to be careful of other causes of temporary decreases in luminescence (like sunspots).

        In both cases, it really needs repeated observations over time to establish that it's an orbital event and not something random. In the good ol' days of exoplanet discovery when the equipment wasn't so hot & we expected to find planets pretty much like ours, it took a whole lot of observations before anyone was willing to take the risk of announcing a discovery. Now, with better equipment making it easier to detect hiccups in a star's routine and a more open attitude about how planets behave, discoveries are being announced a lot earlier in the observation process.

        To be fair, TFA does give itself a whole lot of wiggle room in interpreting the data. It just fails to mention that follow-up observations aren't confirming the orbital parameters of the assumed planet.
  • Bad Data (Score:5, Interesting)

    by SpaceMika (867804) on Wednesday October 08, 2008 @08:30PM (#25307663)
    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).
    • by bh_doc (930270)
      Links to said astro mailing lists, esp. their archives?
    • Re:Bad Data (Score:4, Informative)

      by ceoyoyo (59147) on Wednesday October 08, 2008 @10:21PM (#25308511)

      Uh, we know of a bunch of Jupiter or larger sized planets in closer than Mercury orbits. This isn't anywhere near the first. It's density is it's unique trait.

    • Re: (Score:3, Insightful)

      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!

      The same thing happened 3-4 weeks back with TW Hydrae b [universetoday.com].

      NASA and the ESA's sites still claim this one is valid.

      Maybe you could post an excerpt from one of the emails?

  • by MarkusQ (450076) on Wednesday October 08, 2008 @08:32PM (#25307693) Journal

    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

    • by Nyall (646782)

      density is unitless ?

      • Caught me (Score:3, Informative)

        by MarkusQ (450076)

        density is unitless ?

        In some systems, yeah, it is. Set c=1 (space-time unification), measure masses and energies in the same units (E=mc^2), and so on. But I (obviously) wasn't using one of those systems, I was using g/cm^3, as you probably realized.

        --MarkusQ

        • Re:Caught me (Score:4, Informative)

          by Artifakt (700173) on Wednesday October 08, 2008 @11:19PM (#25308901)

          Density isn't exactly dimensionless, but if you set things up so the density of water is 1 in a system of measurements, the densities of other things (i.e. Lead, Iridium, or this planet) will come out the same numbers, regardless of the units used. So it's not necessary to really specify the units, just that H2O at STP = 1 in whatever system you are using.

          • Density isn't exactly dimensionless, but if you set things up so the density of water is 1 in a system of measurements, the densities of other things (i.e. Lead, Iridium, or this planet) will come out the same numbers, regardless of the units used. So it's not necessary to really specify the units, just that H2O at STP = 1 in whatever system you are using.

            That is the sort of unlabeled density I was throwing around in the first place, but IIRC there are some systems in which it truly dimensionless. To get

    • given that the entire planet is appearing smaller than it should be, could it not just be further away?

    • by mswope (242988)

      My first thought is similar to yours - if it's that far out of the norm, it's probably a calculation error.

    • ... or its own considerable gravity increases its density.
    • Re: (Score:3, Informative)

      by ceoyoyo (59147)

      The core of a brown dwarf has a density somewhere between 10 and 10^3 g/cm^3. That means the cores of brown dwarfs have to be either:

      • Enormous lumps 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
      • Something that's not in your list (like compressed gas)

      Guess where I'd put my money....

      Seriously: brown dwarfs all have about the same radius as Jupiter, but range in mass up to about 60 times that

      • * Something that's not in your list (like compressed gas)

        Guess where I'd put my money....

        Seriously: brown dwarfs all have about the same radius as Jupiter, but range in mass up to about 60 times that of Jupiter. Since Jupiter's density is about 1.3 g/cm^3, brown dwarfs can have average densities (not just the core) up to about 70 g/cm^3. More than twice the density of this thing.

        Brown dwarfs don't get to that density by gas compression. The reason the size flattens out is that they reach a point w

        • by ceoyoyo (59147)

          Ah, my mistake. When I read your list it seemed you were going for the last option as the obvious one. Seeing as how this object's density is pretty much exactly in line with what you'd expect from a brown dwarf, I should have realized that you actually meant that one.

          You really should save the adjective "ultra-compact" for really compact degenerate matter though. Also, at 20 Jupiter masses that thing isn't going to be supported mostly by degeneracy pressure either, so it will be composed mostly of non-d

          • Ah, my mistake. When I read your list it seemed you were going for the last option as the obvious one. Seeing as how this object's density is pretty much exactly in line with what you'd expect from a brown dwarf, I should have realized that you actually meant that one.

            No, you were right in your interpretation, I was mostly betting on data error, though brown dwarf would be a good second bet. I'm going off a physics education that's got twenty plus years of dust on it and half these posts have been made wi

    • How dense is the Death Star?

      I bet more than 4/3....

    • Re: (Score:2, Interesting)

      by w0mprat (1317953)
      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
    • by VShael (62735)

      The article says 21 times more massive. Not 21 times more dense.
      You may be making an invalid assumption.

      I'll grant that the liklihood of it being a gas giant is near zero, since the solar wind would strip the gas from the planet, but there's nothing in the article to say it's 21 times more *dense* than Jupiter.

      • by 4D6963 (933028)

        The article says 21 times more massive. Not 21 times more dense.

        I don't know how massive you are, but now I know how dense. If the two are the same size hence the same volume and that one is 21 times more massive than the other, then it's 21 times more dense. Density is function of mass and volume, and if volume is constant then it's proportional to mass.

        Well to be precise a link from TFA says that the planet's radius is 1.01 (± 0.07) Jupiter radiuses (note how 1.00 is well within that range), and that its mass is 21.66 (± 1) Jovian masses. Which

  • by mccalli (323026)
    I suggest they call it Ix. Which means, of course, "member of a new-found family of very massive planets that encircle stars more massive than the sun". Obviously.

    Cheers,
    Ian
  • that the faster an object is moving the more massive it is. Now if it's the size of jupiter and it is orbiting its sun in only 4 hours then even if it were really close to the sun it would still be moving really really quickly. I know they probably take the speed into consideration when determining its mass. But it's fun to think about.
    • Not really, planets don't move at relativistic speeds. However according to you standard physics text books trains do. Oh and TFS said 4 days not hours

      • So... you're saying, the planet is being pulled by some sort of space train? Stop the presses! Scientists have discovered space trains!

    • that the faster an object is moving the more massive it is. Now if it's the size of jupiter and it is orbiting its sun in only 4 hours then even if it were really close to the sun it would still be moving really really quickly.

      If this were the case, you would probably have very severe tidal motions of the layers on Jupiter. The increased friction would probably cause the planet to slow down if it were close to the sun.

  • Diameter in gas giants does not correlate well to mass. If Jupiter were significantly more massive than it is it would actually be smaller as it's density would increase.
  • by aarenz (1009365)
    It is a combination of a dyson sphere and the death star.
  • Entitled _Satan's Planet_?

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