Dwarf Planet ‘Biden’ Hints At Planet X At Solar System’s Edge

Artist’s view of a remote icy asteroid with the sun in the distance. Astronomers recently announced the discovery of 2012 VP113, the most distant asteroid ever seen. Credit: NASA/JPL

Asteroids have been hot this week. Just days after discovering the first asteroid with rings, astronomers reported the discovery of a new dwarf planet that orbits farther from the sun than anything else ever seen. It’s called 2012 VP113, but the discovery team prefers the more playful ‘VP’ or ‘Biden’ for short.

Photographs of 2012 VP113 as it slowly moves across the sky. It was discovered with the new Dark Energy Camera at the National Optical Astronomy Observatory’s 4-meter (157-inch) telescope in Chile. Click to learn more about the instrument. Credit: Scott Sheppard / Carnegie Institution for Science

2012 VP113 gets no closer than 7.4 billion miles or 80 times Earth’s distance from the sun. That’s more than twice Pluto’s distance. But the mind reels when you realize that 2012 VP113 loops out to 44 billion miles (70 billion km) distance when at it most distant point from the sun plying an orbit that takes 4,000 years to complete!

Assuming average reflectivity, 2012 VP113 is 280 miles (450 kilometers) in diameter, potentially placing it in the dwarf planet category like Pluto and several other largish solar system objects too small to be planets but large enough for gravity to have crunched them into spherical shapes.

2012 VP113 moved between each image as seen by the red, green and blue dots. The background stars and galaxies did not move and thus their red, green and blue images combine to show up as white sources. Credit: Scott S. Sheppard/Carnegie Institution for Science

‘Biden’ joins the previous distance record holder, Sedna, as one of only two bodies found in the inner Oort Cloud, a reservoir comets, some of which eventually find their way into the inner solar system to the delight of skywatchers.

“The detection of 2012 VP113 confirms that Sedna is not an isolated object; instead, both bodies may be members of the inner Oort Cloud, whose objects could outnumber all other dynamically stable populations in the Solar System,” authors Scott Sheppard and Chadwick Trujillo wrote in their discovery paper, published this week in Nature.

Cross section of the solar system the familiar inner and outer planets plus the more distant Kuiper Belt and the remote Oort Cloud. Credit: NASA

The known solar system is divided into half a dozen zones: the inner, rocky planets which includes the Earth; the inner asteroid belt where the traditional rocky asteroids reside; the giant outer planets; the Kuiper Belt, reaching from 2.8-4.6 billion miles from the sun, that includes Pluto and countless other icy asteroids; the inner Oort Cloud that Sedna and ‘Biden’ call home and finally the remote outer Oort Cloud located between 5,000 and 100,000 times Earth’s distance from the sun.

Orbits of Sedna and 2012 VP113 are shown along with the Kuiper Belt and out planets (purple circles). The sun is at center. It’s empty out there! Dwarf planets Sedna and 2012 VP113 are the only known objects in the inner Oort Cloud. Credit: Scott S. Sheppard/Carnegie Institution for Science

Billions of icy, inert comets are believed to exist in this last, more remote region of the solar system. Disturbed by the gravity of passing stars, Oort Cloud comets can “drop in” to the inner solar system. Their orbital periods can easily be a million years or longer.

But back to 2012 VP113 and Sedna. Because only a tiny amount of sky has been examined for faint objects like these two planetary dwarfs,Trujillo and Sheppard estimate that some 900 objects with similar orbits and up to 620 miles (1000 km) across are still waiting to be found.

The total population of the inner Oort Cloud may be even larger than the inner asteroid belt and Kuiper Belt combined. Most intriguingly, some of these objects could be as big as Earth or Mars. Only their extreme faintness makes their discovery a painstaking process, says Sheppard.

View from the surface of the remote Oort Cloud planetoid Sedna, looking back towards the Sun and the inner Solar System. The view would be similar from 2012 VP113. Credit: NASA/ESA/ A. Schaller

The similarity in the orbits of Sedna, 2012 VP113 and several other objects in the Kuiper Belt suggests that an unknown massive body perhaps even larger than Earth exerts a gravitational influence on the bunch. But before Planet X aficionados jump out of their seats, don’t forget the results of NASA’s WISE satellite survey. Seeing the sky in infrared light, which can reveal even cold, dark objects at great distances across the solar system, nothing even close to a planet-sized object was discovered.

WISE’s two complete infrared sweeps of the sky found that no object the size of Saturn or larger exists out to a distance of 930 billion miles from the sun and no object larger than Jupiter exists out to 2.4 trillion miles. That doesn’t negate the possibility that something Earth-sized remains hidden in that profound darkness.

Who knows?? What’s perhaps most fascinating in all of this is how our view of the solar system has matured from nine planets to a much more complex place with room for many more possibilities than we might have imagined a generation ago.

12 Responses

  1. Hunter

    Great article Bob. Been waiting for your thoughts on this since I read about it earlier this week. Although our friend WISE says otherwise, with the highly elongated orbits of Sedna and now “Biden” it’s always fun to keep speculating of a large mystery object lurking deep in the outer solar system just waiting to be discovered. I look forward to the future as astronomers keep discovering more and more about the outer solar system.

    1. astrobob

      Thanks Hunter! I wanted to write about it the day the news broke but as sometimes happens, I had a different blog planned for that day. I feel the same as you – solar system discoveries are coming fast and furiously. Later this year Rosetta will orbit a comet; next year Dawn will study Ceres and New Horizons will make a flyby of Pluto. Incredible things yet to come.

    2. Kevin Heider

      What WISE says is that there is not a large gas giant like Jupiter or Saturn perturbing objects like Sedna and 2012 VP113. But that does not mean a several Earth mass object could not exist somewhere between 250-1500AU from the Sun. WISE can not see objects cooler than 70-100K.

  2. Sean

    For some reason i always thought the Oort cloud was within the solar wind’s influence and not in interstellar space. so i guess interstellar space is defined according to the reach of solar plasma, while what is considered to be part of the solar system (Oort cloud included, for example) is defined by the reach of solar gravitation. or something. so by this definition both Voyagers are still within the solar system, right?

    1. astrobob

      Yes, the edge of the sun’s influence vis-a-vis the local solar plasma versus interstellar plasma is around 121 AU in Voyager 1’s direction, but the gravitational influence of the sun extends far beyond this to the Oort Cloud. Out way beyond that really, but too weak to matter. By the magnetic/plasma influence definition, the Oort Cloud is in interstellar space but by the more familiar gravity concept, it’s still part of the solar system. What your most interesting observation does imply is that objects like 2012 VP113 spend part of their orbit within the sun’s magnetic/plasma influence and a fair part in the interstellar magnetic field. This is fascinating to think about. Back to Voyager. Since it reached escape velocity long ago and finally crossed into interstellar territory, it’s not bound to the sun anymore the way “Biden” and the Oort Cloud are. It and the four other escaping spacecraft (Pioneer 10, 11, Voyager 2 and New Horizons) are unique that way. Thanks for your comment on this.

  3. Roy

    Hey ! Didn’t we used to have a planet called Uranus !?!?! How did NASA go and lose a whole planet ?!?!?

    1. astrobob

      Hi Roy,
      It appears they also lost Mercury and Venus. I’m guessing all three planets weren’t relevant to the “big picture” shown in the diagram.

  4. A sampled core of one of those OCO’s (Oort Cloud Object) would contain billion of years of collected high-energy particles from interstellar environment buried into the exotic ices of the body. The navigational trick is to catch them during their rare presence in the Sol’s heliosphere.
    When are we leaving ? 🙂

    1. astrobob

      No doubt many stories to tell after billions of years of bombardment! I’ve read recently about the capture of interstellar grains by Stardust. Will be writing about it soon.

  5. mauricemaltais


    Si pour une raison cette planète s’approcherait de la terre cela provoquerait-il des changements à la terre.

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