V774104

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 must been perturbed by something, but 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 7012747989353500000♠50 AU and a semi-major axis greater than 7013224396806050000♠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]} At the time of its discovery, the Voyager and Pioneer 10 spacecraft were also more distant; the Voyager probes are observable via their artificial radio transmissions.

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

• Discovery and exploration of the Solar System
• List of Solar System objects most distant from the Sun in 2015
• U (TNO)

Notes

References

2015 in space
Launches	Space probes LISA Pathfinder SMAP Space observatories Astrosat DSCOVR
Impact events	2015 Kerala meteorite 2015 Thailand bolide WT1190F impact
Selected comets	15P/Finlay C/2014 Q2 (Lovejoy) 88P/Howell 22P/Kopff 10P/Tempel C/2013 US10
Selected NEOs	Closest asteroid approaches in 2015 2015 BP513 (357439) 2004 BL86 2015 AZ43 1566 Icarus 2015 TB145 2007 VE191 (33342) 1998 WT24 (85989) 1999 JD6 2015 SO2
Exoplanets	Aldebaran b β Circini b EPIC 2037 b EPIC 2037 c Gliese 1132 b HD 155233 b HD 164595 b HD 219134 b HIP 11915 b KELT-4Ab Kepler-438b Kepler-440b Kepler-442b Kepler-444 Kepler-451b Kepler-452b Kepler-453b K2-3d K2-22b Wolf 1061c
Galaxies	WISE J224607.57-052635.0
Space exploration	Dawn (orbiting Ceres) Rosetta (orbiting Comet Churyumov–Gerasimenko) MESSENGER (end of mission) New Horizons (flyby of Pluto) Akatsuki (orbiting Venus)
Selected discoveries	V774104 (a TNO)
Category:2014 in space — Category:2015 in space — Category:2016 in space