V774104

V774104
Discovery[1]
Discovery site Subaru Telescope
Discovery date 13 October 2015
Orbital characteristics
Observation arc ~2 weeks as of last report[2]
Physical characteristics
Dimensions 500–1000 km[1][3]
~24[1][lower-alpha 1]
~4[1][4]

    V774104 is a trans-Neptunian object (TNO) with a radius roughly half that of Pluto or somewhat smaller. Currently it is approximately 103 AU from the Sun,[5][6] a distance of 15.4 billion kilometers (9.6 billion miles).[7] As of the discovery announcement in November 2015, it is the most distant observed object in the Solar System.[6][8] No astrometry has been submitted to the Minor Planet Center, so there are no publicly known orbital elements.

    Discovery

    The object's discovery telescope, Subaru (Japanese name for the Pleiades) on the far left, alongside the twin Keck telescopes and NASA's Infrared Telescope Facility

    V774104 was discovered by a team using the Subaru Telescope, a large reflecting telescope at the summit of Mauna Kea with a primary mirror 8 meters (26 ft) in diameter.[3] The discovery was announced at the November 2015 meeting of the American Astronomical Society’s Division for Planetary Sciences; the discovery team was led by Scott Sheppard and Chad Trujillo.[8]

    Orbit

    No astrometry has been released publicly so the object does not have a minor planet designation and the uncertainties of the orbital elements are unknown. Being a trans-Neptunian object so far from the Sun with an observation arc of just a few weeks at the time of its discovery announcement,[2] its perihelion and aphelion have not been securely determined.[lower-alpha 2]

    Possible sednoid

    The orbit of Sedna (in red), the prototypical sednoid, set against the orbits of Pluto (purple) and the outer planets

    V774104 might be a sednoid, an enigmatic class of objects in the outer Solar System with only two known members. Sednoids have eccentric orbits that have to have been perturbed by something, but that could not have been perturbed by any presently known body (their entire orbits lie well outside the influence of Neptune). To be a sednoid, V774104 must have a perihelion greater than 50 AU and a semi-major axis greater than 150 AU, which can be determined when its observation arc is around one year. Only 3 objects are known to have perihelia (closest approach to the Sun) greater than 50 AU: 90377 Sedna, 2012 VP113, and 2004 XR190.[10][11] But 2004 XR190 has a low orbital eccentricity with perihelion at 51 AU.[10] Sedna and 2012 VP113 have both had their perihelion point lifted well beyond the classic Kuiper belt of 30–50 AU. If V774104 is a sednoid or extreme trans-Neptunian object, it may point towards an undiscovered shepherding planet hundreds of astronomical units from the Sun.[3][7] It is also possible, however, that the lifted perihelion was a result of the crowded confines of the open star cluster in which the Sun formed.[3] Discovery of additional sednoids and analysis of their orbits should eventually permit identification of the process by which their orbits were disturbed.[12]

    Most distant Solar System object

    Many news sources heralded V774104 as "the most distant Solar System object".[8] In fact, various long-period and hyperbolic comets are more distant,[7] though all of these are much smaller bodies and not observable at such distances.[lower-alpha 3][lower-alpha 4]

    Most-distant known objects in the
    Solar System as of 26 February 2016[13]
    Object name Distance from the Sun (AU) Magnitude
    (vmag)
    Current Perihelion Aphelion
    V774104 103 N/A N/A 24
    Eris 96.3 37.8 97.6 18.7
    2007 OR10 87.5 33.0 100.8 21.7
    Sedna 85.7 76.0 939 21.0
    2014 FC69 84.2 40.3 106.9 24.1
    2006 QH181 83.4 37.8 96.7 23.6
    2012 VP113 83.3 80.5 438 23.4
    2013 FY27 80.3 36.1 81.8 22.1
    2010 GB174 70.8 48.7 693 25.1
    2000 CR105 60.5 44.3 412 23.9
    2008 ST291 59.9 42.4 154.5 22.2
    2003 QX113 59.9 36.7 62.1 22.5
    Including all known objects currently located at least twice as far as Neptune.[13]
    See List of trans-Neptunian objects for more.

    Observed Solar System objects that periodically become more distant than 103 AU from the Sun include Sedna (which is similar or modestly larger in size), 2000 CR105, 2012 DR30, 2013 BL76, and 2005 VX3. There are 595 known objects that have aphelia more than 103 AU from the Sun.[14] This distance is about double the outer limit of the torus-shaped Kuiper belt that lies outside Neptune's orbit. Far beyond this region is the vast spherical Oort cloud enshrouding the Solar System, whose presence was deduced from the orbits of long-period comets.

    Study of the population of Solar System objects that are significantly more distant than V774104 will likely require new instruments. The proposed Whipple spacecraft mission is designed to determine the outer limit of the Kuiper belt and directly detect Oort cloud objects out to 10,000 AU. Such objects are too small to detect with current telescopes except during stellar occultations. The proposal involves use of a wide field of view and rapid recording cadence to allow detection of many such events.[15]

    See also

    Notes

    1. ↑ The size estimate of 500–1000 km leads to an absolute magnitude (H) of 3.5–4.0, which at 103 AU is apparent magnitude 24–24.5.
    2. ↑ For comparison Trans-Neptunian object 2015 SO20 with an observation arc of only 28 days had large uncertainties for perihelion and aphelion.[9]
    3. ↑ For example, as of 2015, comet C/1927 X1 (Skjellerup-Maristany) is 109 AU from the Sun
    4. ↑ At the time of discovery, the Voyager and Pioneer 10 spacecraft were also more distant, the Voyager probes are observable via their artificial radio transmissions.

    References

    1. 1 2 3 4 Kelly Beatty (21 November 2015). "V774104: Solar System’s Most Distant Object". Sky & Telescope. Retrieved 2015-11-22.
    2. 1 2 Cofield, C. (2015-11-12). "New Dwarf Planet In Our Solar System May Be The Farthest One Yet". Space.com. Retrieved 2015-11-13.
    3. 1 2 3 4 "Most distant solar system object yet could hint at hidden planet". New Scientist. 10 November 2015.
    4. ↑ "Absolute Magnitude (H)". NASA/JPL.
    5. ↑ WIRED, Solar System's most distant object hints at hidden planet
    6. 1 2 Hand, E. (2015-11-10). "Astronomers spot most distant object in the solar system, could point to other rogue planets". News.ScienceMag.org. AAAS. Retrieved 2015-11-11.
    7. 1 2 3 Astronomy Now Magazine – Newly discovered dwarf planet is solar system’s most distant object
    8. 1 2 3 BBC News, Most distant' Solar System object spied
    9. ↑ "JPL Small-Body Database Browser: (2015 SO20)" (last observation: 2015-10-18 ; arc: 28 days). Jet Propulsion Laboratory. Retrieved 2015-11-13.
    10. 1 2 "JPL Small-Body Database Search Engine: q > 50 (AU)". JPL Solar System Dynamics. Retrieved 2015-11-12.
    11. ↑ "Minor Planet Center: q > 50 (AU)". Minor Planet Center. Retrieved 2015-11-12.
    12. ↑ Schwamb, M. E. (2007). "Searching for Sedna's Sisters: Exploring the inner Oort cloud" (PDF). Cal Tech. Archived from the original (PDF) on 2013-05-12. Retrieved 2015-11-15.
    13. 1 2 "AstDyS-2, Asteroids - Dynamic Site". 2016-02-26. Retrieved 2016-02-29. Objects with distance from Sun over 59 AU
    14. ↑ "JPL Small-Body Database Search Engine: Q > 103 (AU)". JPL Solar System Dynamics. Retrieved 2015-11-12.
    15. ↑ The Whipple Mission Exploring the Oort Cloud and the Kuiper Belt – C Alcock et al.


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