New Dwarf Planet Redefines Edge of Our Solar System

By Bill Andrews | March 26, 2014 1:07 pm
The discovery images of 2012 VP113. The dwarf planet moved between each image as seen by the red, green and blue dots. Credit: Scott S. Sheppard/Carnegie Institution for Science

The discovery images of 2012 VP113. The dwarf planet moved between each image as seen by the red, green and blue dots. Credit: Scott S. Sheppard/Carnegie Institution for Science

Even after all these years, the solar system can still surprise us. Not just with the occasional new rock — a nifty asteroid, or interesting comet — but sometimes we even find new minor planets and, if really lucky, an entire new region.

Now astronomers have done just that: findings announced today suggest there’s a never-before-seen minor planet orbiting the sun beyond Pluto. And, beyond that, it’s possible a major planet is hiding out in the darkest, farthest regions of the solar system too. If the researchers are right, their discovery would redefine the edges of our planetary neighborhood.

Solar system anatomy

We have a solid grasp of the innermost parts of the solar system: the rocky planets and asteroids closest in, from 0.39 to 4.2 astronomical units (or AU, equivalent to the average Earth-sun distance of about 93 million miles); gas giants from 5 to 30 AU; and Kuiper belt objects (like Pluto and Eris) between 30 and 50 AU. Far beyond that, we expect to find the Oort cloud, a roughly spherical distribution of cold, dark icy bodies too far away to make out clearly.

Astronomers knew of only one object that orbited more than 50 AU away, as defined by its perihelion, the closest it gets to the sun: Sedna. Discovered about 10 years ago and about 1,000 km (600 miles) wide, it’s almost certainly a minor planet like Pluto, but its enormous distance (with a perihelion of about 76 AU) makes it hard to know for certain. Since then, we thought Sedna was one of a kind, the only known object that occupied the space beyond 50 AU, the well-defined edge of the observable solar system. Until now.

More Like VIP113

orbits

Orbit diagram with the sun and terrestrial planets at the center. The Kuiper Belt (including Pluto) is shown by the dotted light blue region just beyond the giant planets. Sedna’s orbit is shown in orange while 2012 VP113’s orbit is shown in red. Credit: Scott S. Sheppard: Carnegie Institution for Science

Astronomers today announced in Nature the discovery of a new Sedna-like body, named 2012 VP113, with a perihelion of 80 AU. It’s estimated to be 450 km (300 miles) wide, and also likely to be a dwarf planet.

And while the mere fact that we can look at something so tiny and so far away is cool, the important thing is it proves Sedna is not alone. Instead of being some weird unique outlier, the distant world is likely part of a whole new category of solar system objects belonging to the inner Oort cloud. Odds are scientists will keep finding more and more of this type of world out there (the study’s authors estimate about 900 such objects), which will help astronomers understand more about the solar system’s dynamics.

Perhaps most intriguingly, and still fairly speculatively, the findings also suggest the presence of another large planet in the outer reaches of the solar system. When the authors plotted the motion of Sedna, 2012 VP113, and distant Kuiper belt objects, they noticed some odd behaviors which they couldn’t explain — but which a massive, “super-Earth” planet about 250 AU away could. They note that such a dimly lit planet “would be fainter than current all-sky survey detection limits, as would larger and more distant perturbers” (i.e., planets), so it’s certainly possible… but right now it’s little more than a guess. A weird, intriguing guess.

 

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: solar system
  • http://blogs.discovermagazine.com Tim Fisher

    Bring on the Planet X consipiracy theories!

    • Guest

      so you can feel better about yourself and say, “Told you so”?

    • David Carlson

      I’ve got a Planet-X killer theory I’ve been working on for about 7 years now about a Companion star that is no more, that ‘recently’ drifted away:

      Planet X only purports to explain the orbits of Sedna, VP-113 and other extended-disk TNOs, but wait ’till you hear what a former Companion star explains:

      – Sedna and ‘Biden’ (2012 VP-113) orbits
      – Late Heavy Bombardment
      – EXTRATERRESTRIAL Cambrian Explosion of life in dwarf-planet oceans at 542 Ma
      – Great Unconformity
      – All Eon transitions in Earth’s history
      – EXTRATERRESTRIAL continental tectonic plates as aqueously-differentiated dwarf-planet cores
      – Extinction events on Earth
      – Formation of super continents
      – Snowball Earth
      – Venus’ retrograde orbit and its ‘continents’

  • Richard E Warsin

    That really is a surprise! The universe never ceases to amaze and intrigue me.

  • Beckoning Chasm

    The tenth planet is Mondas, and there’s trouble there.

    • Buddy199

      It definitely sounds like an enemy planet.

  • Big Hit Sports

    Look at the orbit of VP113! Imagine what else could be orbiting our sun that is just on the other end of their orbit around the sun!

  • DrKrypton

    put a communications probe on it to send us data on it and anything it encounters. like other planets.

  • Jeff

    I’m hoping for a brown dwarf.

  • Laurel Kornfeld

    Pluto, Eris, and all dwarf planets are NOT “minor planets,” as the term “minor planet” is a synonym for asteroids and comets, objects not large enough or massive enough to be in hydrostatic equilibrium. Nor are Pluto and Eris simply Kuiper Belt Objects, of which there are thousands. Pluto and Eris are small planets, and if 2012 VP113 is in hydrostatic equilibrium, it is a small planet too (as is Sedna). I genuinely hope a large planet is found out there in the Oort Cloud because it would blow the disastrous, horrible IAU definition out of the water. Nothing that far out could clear its orbit of Oort Cloud objects, meaning even a giant planet out there would be considered a dwarf planet by the IAU, showing just how ridiculous their definition really is.

    • April Deming

      You need to look up the official definition of planet. Your beliefs are outdated.

      • Donovan Tagupa

        Aww snap. This reply turned me on for some reason.

      • Laurel Kornfeld

        No, I don’t. I know the IAU definition, and I reject it as anything other than one point of view in an ongoing debate. There is nothing special about the IAU that makes their definition “official,” no matter how much they want to believe so. In fact, 96 percent of IAU members never even voted on this; they didn’t have the chance to because no absentee or electronic voting was allowed. The vote itself was done in violation of the IAU’s own bylaws. And an equal number of professional astronomers signed a formal petition rejecting the IAU definition. My beliefs are not outdated. They are an informed, educated view based on having studied astronomy and having done in depth research about just how that vote was conducted. I suggest you read the book “The Case for Pluto” by Alan Boyle.

        • April Deming

          My 3 year old has a book, called, “Pluto’s Secret”. It can explain the simplicity of this matter. There are thousands of “dwarf planets” in the Kuiper Belt, but the IAU only recognizes 5 of them, of which one of the 5 is Pluto. There is definitely a huge difference between the objects in the Kuiper Belt and the 8 large planets that orbit our sun. I believe when they became aware of the thousands of objects in the Kuiper belt, they realized they needed to start differentiating them from the 8 planets.

          • Laurel Kornfeld

            I am familiar with the book, but I will add that things are not as simple as you say. There are two kinds of objects in the Kuiper Belt. The overwhelming majority are tiny, shapeless asteroids and comets. Those are hugely different from the larger planets. However, there are also some larger objects that are large enough and massive enough to be squeezed into a round shape by their own gravity. These objects have more in common with the larger planets than they do with the majority of tiny Kuiper Belt Objects. They have complex processes such as geology and weather. Pluto is differentiated into core, mantle, and crust just like Earth is. Pluto may even harbor a subsurface ocean. These objects comprise a third class of planets known as dwarf planets. They do not need to be differentiated from the eight larger planets. Those comprise other subclasses of planets, terrestrials and jovians. The fact that some smaller planets are located in the Kuiper Belt does not make them not planets. An object can be both a Kuiper Belt Object and a planet if it is shaped by its gravity. Kuiper Belt Object tells us where they are while small planet tells us what they are. There are more dwarf planets than the ones the IAU recognizes though probably not thousands. None of them share the same orbits with one another except Pluto and Charon, which are actually a binary planet system. The fact that there may be a large number of dwarf planets has no bearing on their being planets. If our solar system has hundreds of planets, then that is what it has. The key point that differentiates planets from non-planets in any location is whether they are large enough and massive enough to be shaped by their own gravity. If the answer is yes, then they are planets, just of a different subcategory.

          • Big Trav

            You are a smart lady Laurel, and I agree with your arguments whole heartedly as do the majority of the astronomical world who have just re declared Pluto a planet! As it is currently in its point of orbit far outside that of neptune it is the farthest known planet in our solar system, Until they find the supposed massive planet beyond Sedna

  • Iam angie

    The large planet is planet X. They have known about this since the 1980’s.

  • Derek Hall

    Tip for SF authors – an alternative universe, being imaginary, won’t (or shouldn’t) make your stories appear out-of-date when reality pulls a bunny from the hat/a planet from the outer reaches of the solar system/more planetary systems around distant stars than you can shake a stick at…

  • Arthur Smith

    I’m curious how it is we can see some of the oldest, farthest galaxies in the universe, but we can’t see much closer, to planets in our outer solar system. I guess it’s because they don’t produce light?

    • Tim1980

      They don’t reflect light or light doesn’t pass through their atmospheres. The reason we can see planets at far a flung stars is because of their proximity to their stars and when they orbit them see can see the diffusion of light and see the elements in the atmosphere by the hue of the diffused light. exo planets >50 AU do not often pass between us and a light source, also the Kuiper belt and the rest can get in the way, plus their orbits are irregular.

  • Laurel Kornfeld

    2012VP113 and Pluto are NOT minor planets. The term “minor planet” is a synonym for asteroids and comets, as explained by Dr. David Weintraub in his book “Is Pluto A Planet?” Dwarf planets are a third class of planets, significantly different from asteroids and comets because they are squeezed into a round shape by their own gravity, making them complex objects that often have geology and weather. Blurring the distinction between these two very different types of bodies is simply bad science.

  • Jennifer Anne Bangstrom

    Welcome to the solar system, little buddy.

  • http://blogs.discovermagazine.com Tammara Xx

    “the 12th planet” from zecharia sitchin and the sumerians.

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