V774104: Solar System’s Most Distant Object

An ultra-deep survey has turned up a sizable object situated nearly 10 billion miles from the Sun — more distant than any known solar-system object.

Prowling the outer Kuiper Belt for large, distant members of our solar system has turned up a zoo of remarkable finds in recent years. There's Eris, for example which triggered a divisive debate about Pluto's planetary status; Sedna, whose orbit carries it out to more than 900 astronomical units (1 a.u. is the mean Earth-Sun separation); and 2007 OR10, both very distant (87 a.u.) and one of the reddest objects in the solar system.

V774104 discovery images

This animation of two discovery images for the very distant solar-system object V774104 show it shifting with respect to background stars. This is not from the object's orbital motion, which is far too slow, but rather due to parallax as Earth shifted its location between the two exposures. The frame is 0.7 arcminute wide.
S. Sheppard / C. Trujillo / D. Tholen / Subaru Telescope

But at last week's meeting of the American Astronomical Society's Division for Planetary Sciences, Scott Sheppard (Carnegie Institution for Science) announced that he, Chad Trujillo (Gemini Observatory), and David Tholen (University of Hawai'i) have spotted something even farther from the Sun. This body, designated V774104 for now, lies 103 a.u. away in the direction of west-central Pisces — that's 9.6 billion miles or 15.4 billion km.

The object turned up in a pair of images taken October 13th with Japan's 8-meter Subaru Telescope atop Mauna Kea. The animation at upper right shows the motion of V774104 in the 5½-hour interval between the two images. "We detect the motion of solar system objects by parallax and not by the actual movement of the object," Sheppard explains. An object around 100 a.u. away will shift about 1.3 arcseconds per hour, he says, so it's easily detected in a few hours.

V774104 is so distant that it will take another year of study to determine its orbit. "All we really know is the distance," Sheppard admits, along with a guess as to its size. Given its brightness — just 24th magnitude — and assuming that its surface is 15% reflective, the object might be 500 km across. The researchers will make follow-up observations in early December with one of the 6.5-m Magellan telescopes in Chile.

What Kind of Orbit?

Dynamicists will be eager to learn what kind of orbit V774104 occupies. A highly eccentric track would mean that it periodically swings much closer to the Sun. That's the case with Eris, which likely got flung into its 558-year-long orbit after a gravitational encounter with Neptune eons ago.

Location of V774104

Beyond its distance and estimated size, astronomers know little about the distant object V774104. Within a year, they hope to determine the characteristics of its orbit around the Sun (small yellow dot at center). The outermost pink circle denotes Neptune's orbit.
Source: Scott Sheppard / Carnegie Inst. for Science

But if the orbit is more circular, or if V774104 was found near perihelion, then it's completely decoupled from the massive planets — and that will cause dynamicists to question how it got out there. Two other distant objects, Sedna and 2012 VP113, are also in this kind of orbital limbo. There's no consensus on why they're out there; possible causes run the gamut from gravitational stirring of the even more distant Oort Cloud by a close-passing star to the presence of an undiscovered massive planet far beyond the orbit of Neptune. Or they might be the first-found members of the inner Oort Cloud.

Meanwhile, the search goes on for Sheppard, Trujillo, and Tholen. They're using the Subaru Telescope and the 4-m Blanco Telescope at Cerro Tololo Inter-American Observatory to conduct the largest, deepest survey to date for distant solar-system objects. They hope to find more Sedna-like objects — and Sheppard tells me they've spotted several more objects lying 80 to 90 a.u. away that are being tracked. Should all of these turn out to share orbital characteristics, it would imply that a massive planet awaits discovery in the distant solar system.

10 thoughts on “V774104: Solar System’s Most Distant Object

    1. David Oesper

      Margarita, I think this is a temporary designation assigned by team lead Scott Sheppard pending a provisional designation being assigned by the IAU Minor Planet Center. See http://www.minorplanetcenter.net/iau/info/TempDesDoc.html and http://www.minorplanetcenter.net/iau/info/OldDesDoc.html for more information. For example, when Eris was first discovered, it was given a provisional designation of 2003 UB313 by the IAU (why this hasn’t happened yet for V774104 is a mystery to me). Then, after its orbit was sufficiently well-determined, the IAU assigned it minor planet number 136199. Finally (and this hasn’t happened yet for a large number of minor planets and trans-Neptunian objects), a name was assigned: Eris. As Kelly mentions in his article, they discovered V774104 using trigonometric parallax (with a baseline courtesy of the Earth’s orbital motion!) rather than *its* orbital motion, so we are not yet in position to say anything about the orbit of V774104. I hope that Kelly or someone associated with Scott Sheppard’s team will give us a definitive answer about why “V774104” and what the numeric digits signify. Good question!

      1. MargaritaMargarita

        Yes, I understand about provisional designations and that was the basis of my puzzlement. Where on EARTH (or elsewhere) does V774104 derive from. As a confirmed nit-picker and pedant, this kind of query creates an itch that I have to get scratched!

        So I have just located Dr Sheppard’s office email address and have emailed him my query. Also giving him the link to this page.

        1. MargaritaMargarita

          Twitter can be useful! I tweeted

          Margarita McElroy (@bertbestwi) tweeted at 2:23pm – 2 Dec 15:

          @plutokiller @megschwamb @lukedones @earthskyscience @SpaceRef PLEASE someone tell me – WHY the label “V774104”???? ¿¿ What naming system?? (https://twitter.com/bertbestwi/status/672058565843095553?s=17)

          and got these replies:

          Mike Brown (@plutokiller) tweeted at 5:42pm – 2 Dec 15:

          @bertbestwi @megschwamb @lukedones @earthskyscience @SpaceRef Sheppard & Trujillo made it up. (https://twitter.com/plutokiller/status/672108584587517952?s=17)

          Meg Schwamb (@megschwamb) tweeted at 2:25am – 3 Dec 15:

          @bertbestwi @plutokiller @lukedones @earthskyscience @SpaceRef  it’s an internal designator. likely they give ids to all the objs they find (https://twitter.com/megschwamb/status/672240185111797762?s=17)

  1. capostol63

    Starting from the last sentence of the article, I’d really love to see all these ‘scientists’ who have demoted Pluto’s status, scratching their heads if a massive planet (let’s say the size of Earth?) is indeed found in the distant solar system and, according to their definition, they will have to call it ‘dwarf’!!

    1. MargaritaMargarita

      Has a helpful discussion article, including this:

      “Is the language of the resolution perfect?
      It is not. In an attempt to draft a resolution that was jargon-free and understandable to the public, some scientific rigor was lost. In particular, the language “clearing its orbit” implies that a planet is the dominant body in its neighborhood and gravitationally controls its neighborhood. Some people who are unhappy about the planet definition have claimed that Jupiter or Neptune have not “cleared their orbits”. This reflects a very poor understanding of the resolution and of the science behind it.

      The IAU definition is also imperfect in that it applies only to the solar system. At some point, we will need to revisit the issue in order to establish a classification scheme for exoplanets as well.”

      If any newly found solar system body orbits the Sun, is round (i.e. is in hydrostatic equilibrium) and has “cleared its orbit” then the IAU definition of planet would be applied.

      1. eric.rachut@med.va.gov

        Who’s to blame for misinterpretations of this definition – the ones who devised it or the ones (who seem reasonably well educated in science) trying to understand it? For that matter, just what does “gravitationally control” mean?
        If they had just left Pluto a planet, for historical reasons, we would not be discussing this. Call the other bodies whatever you will. However, we live in an age of absolutism and that would not be kosher.

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