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Newly Found Planetoid Possibly Larger than Quaoar

Posted by michael on from the deep-space-one dept.

I am Jack's username writes "A newly discovered planetoid (Google news cluster) 2004 DW in the Edgeworth-Kuiper belt, where some think objects larger than Pluto exist, may be larger than Quaoar - making it the second largest known trans-Neptunian object and 18th largest object in the solar system."

15 of 46 comments (clear)

  1. Quaoar by daeley · · Score: 2, Funny

    Continuing the uber-Scrabble theme, I'd like the nominate Zzyzx as the new name. Sure, it isn't in any way mythological, but it has nice legends attached to it. And it's halfway to Vegas from here, so what more do you want? ;)

    --
    I watched C-beams glitter in the dark near the Tannhauser gate.
    1. Re:Quaoar by nagudaku · · Score: 3, Funny

      it took them so long to find this ? if they can see the most distant galaxy , is it really so hard to see just beyond pluto ?

    2. Re:Quaoar by TwistedGreen · · Score: 2, Insightful

      Not everyone has a bloody Hubble in their backyard.

      And soon, no one will. :(

    3. Re:Quaoar by PhuCknuT · · Score: 4, Informative

      Yeah, because the most distant galaxies are about 1000000000 (not exact, but you get the point) times larger and brighter than an asteroid 40au from earth. An asteroid or comet only reflects light, so the farther it is from the sun the harder it is to see. A galaxy on the other hand, will have billions of stars, each billions and billions of times brighter than what's reflected from an asteroid.

    4. Re:Quaoar by missing000 · · Score: 2, Insightful

      "Not everyone has a bloody Hubble in their backyard.

      And soon, no one will. :("

      I have to disagree - I think it's more like:

      The Hubble Space Telescope, coming soon to a backyard near you!

  2. Question for the astronomers among us... by Baron_Yam · · Score: 4, Interesting

    Given that stars (excluding the Sun) are point sources as far as our current telescopes are concerned, and these KBOs are discs... what are the odds of a KBO eclipsing a given star during a standard observation period?

    Things I don't know: 1) density of KBOs vs stars 2) apparent speed of KBOs relative to the stars beyond them. 3) The average length of time any star is in a field of observation at a major telescope.

    Actually, there's probably a lot more I don't know, that's just what comes to mind at the moment.

    1. Re:Question for the astronomers among us... by sdedeo · · Score: 4, Informative
      I think the numbers are off relative to each other by many orders of magnitude. The real problem is that both KBOs and stars are essentially points. The chance of accidental overlap is vanishingly small. (If you stuck a telescope and watched a field of stars for brightness variations, you would see a lot of other stuff: eclipsing binaries, orbiting planets, etc -- see the OGLE project, e.g. They have been recently looking for eclipsing planets, but there are huge numbers of contaminants from plain old binary systems.

      You need some mechanism to "increase" the apparent area of the (in this case KBO.) Unfortunately, KBOs are just small rocks, with not too much interesting going on. (Planets that eclipse their own star are easier to see, because they are fixed in the angle they explore on the sky relative to the star.)

      If you're looking for some kind of "eclipse" effect on the background stars, the best way to increase the effective area of your object is to make it heavy enough that it can gravitationally lens something behind it. The lensing effect increases the angular size of the "sweet spot." See the various MACHO searches.

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    2. Re:Question for the astronomers among us... by CheshireCatCO · · Score: 3, Informative

      Well, let me address (although not outright answer) the question you actually posted: the chances of a given KBO occulting a given star are pretty small. Particularly if the star doesn't lie close to the ecliptic...

      That said, the odds of a KBO occulting a star or, perhaps better, any KBO occulting any star aren't all that tiny. Pluto occults stars on occasion. That's how we get data on the atmospheric structure, after all. Admittedly, astronomers keenly search for these occultations, but they do happen every few years or so. Now, mind you, Pluto is a big KBO so that it has a much higher probablity of passing in front of a star than most of the others. Recall that it is, in fact, one of the very few KBOs that have been resolved in our images. (I believe that Quaoar, Charon, Varuna, and perhaps one or two others have been. It's because we have not resolved many of these that we don't know the albedoes/sizes of KBOs that well.)

      The next question is why should we look for occultations? Using them as a means to detect KBOs is probably a waste of time. Occultations can give you a profile of the atmosphere which might not be interesting for most KBOs, although a non-detection would at least tell us something about KBOs in general. (i.e. - That they don't have atmospheres. Not that I think people would be generally stunned by this.)

    3. Re:Question for the astronomers among us... by Birger+Johansson · · Score: 2, Interesting

      Ordinary asteroids in the inner solar system sometimes pass in front of weak background stars (occultations), which provides the opportunity to measure their diameters by timing the disappearence and reappearence of the star. Sometimes such occultations even have revealed the asteroid to be binary.
      However, such events are rare, even for close-by asteroids. The angular diameter of far-away Kuiper-Edgeworth objects is so small that they almost never pass in front of a catalogued star.
      -The basic idea is sound, it is just very unlikely that a K-E object will pass in front of a star that is under observation.

    4. Re:Question for the astronomers among us... by Gary+Bernstein · · Score: 3, Interesting

      The answer is: choose a star near the ecliptic plane of the Solar System and watch it carefully. About once per thousand years, a KBO will pass in front of it. This will make it dim out for a little less than a second, on average. This is a good way to look for small KBOs, not the rare big ones like 2004 DW. Seem like a tough job? It gets easier if you can watch many thousands of stars at a time, then you might see a few events per year. This is exactly what will soon be attempted by my friends at the Taiwanese-American Occultation Survey (TAOS). Should be starting up later this year.

  3. namers by lambent · · Score: 4, Funny

    From the article:

    "After the object is numbered, then the discoverers (that's us) have one decade to propose a name to the Internation Astronomical Union. There are even more rules about the name of the object. 2004 DW, for instance, must be named after an underworld diety because it is in a Pluto-like orbit."

    Okay, everyone ... we have 10 years to come up with a better name than Quaoar. Get to it.

  4. Almost by WTFmonkey · · Score: 4, Funny

    Tiny pieces of The Hubble Telescope, coming to a backytrd near you!

  5. Comparing trans-Neptunian objects by geoswan · · Score: 2, Interesting
    The discoverers of this object keep refering to which of these objects are closer than others of them. Well, hold on, they are all in a 3:2 resonance with Neptune, orbiting the sun twice for every three orbits Neptune makes.

    So, is it really all that meaningful to compare them based on their distance from us today? If they all share the same period don't they all have the same, um, I don't know what it would be called... But their kinetic energy per unit mass would all be the same.

    If they all have the same period, then wouldn't their average distance from the Sun be directly proportional to the eccentricity of their orbit?

  6. Freeman Dyson, KBO's, and small telescopes by Latent+Heat · · Score: 2, Informative
    Freeman Dyson had floated a proposal that I believe I had seen written up in Sky and Telescope. The idea is that you have a whole field of, say, 10 inch telescopes hooked up to photodetectors and a computer. Yes, the chances of any one telescope seeing an occultation among the stars in its field of view is small, but you use a large number of cheap telescopes.

    While Dyson was more of a mathematical theory person, his claim to fame is in physics, and along the school of "when your ownly tool is a hammer, everything looks like a nail", that setup is very reminiscent of a particle detector.

  7. chance that amateur discover kuiper belt object by Deep+Watcher · · Score: 2, Insightful

    Amateur astronomers discover new comets all of the time. But what is with kuiper belt objects? Short period comets (less than 200 year orbits) comets originate in the Kuiper Belt, located inside and outside of Neptune's and Pluto's orbits like Kuiper belt objects. But comets have very eccentric orbits so they come in interior part of solar system and then they become brighter so amateurs could discover them (the most comets discovered by astronomers amateur at the moment of discovery have apparent magnitude about 10-15 where smaller number means brighter object).

    Kuiper belt objects have less eccentric orbits and approximately constant distance from Sun so and their apparent magnitude is constant ,magnitude of brightest objects is about 20 and that is greatest magnitude that the most astroamateurs could achieve with their telescopes. For several years now, astronomers have studied the farthest reaches of our solar system only using the full sensitivity of large professional telescopes on the ground without help from amateurs. These professional surveys mostly seek for kuiper belt in plane of ecliptic (plane of earth's orbit and of most other object in solar system). But there is trans-neptunian objects with highly inclinated orbit so there is chance for amateurs to discover brigher kuiper belt object who have high angle from ecliptic. But I think that amateurs don't use that opportunity