is a

trans-Neptunian object A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has an orbital semi-major axis of 30.1 astronomical units (AU). ...

and highly eccentric

centaur A centaur ( ; ; ), occasionally hippocentaur, also called Ixionidae (), is a creature from Greek mythology with the upper body of a human and the lower body and legs of a horse that was said to live in the mountains of Thessaly. In one version o ...

on a

comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...

ary-like orbit in the outer region of the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

, approximately in diameter. It was discovered through the

Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project began in 2000 a ...

by astronomers Andrew Becker, Andrew Puckett and Jeremy Kubica on images first taken on 27 September 2006 (with

precovery In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of a celestial object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This ha ...

images dated to 13 September 2005).

Characteristics

It has a highly

eccentric orbit In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless quantity, dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circu ...

, crossing that of

Neptune Neptune is the eighth and farthest known planet from the Sun. It is the List of Solar System objects by size, fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 t ...

near

perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

but bringing it more than 1,500 AU from the Sun at

aphelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

. It takes about 22,500 years to orbit the

barycenter In astronomy, the barycenter (or barycentre; ) is the center of mass of two or more bodies that orbit one another and is the point about which the bodies orbit. A barycenter is a dynamical point, not a physical object. It is an important con ...

of the Solar System. The large

semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the longe ...

makes it similar to and . With an absolute magnitude (H) of 8.1, it is estimated to be about 60 to 140 km in diameter. Michael Brown estimates that it has an

albedo Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...

of 0.08 which would give a diameter of around 110 km. The object could possibly be a

. The discoverers hypothesize that the object could come from the

Hills cloud In astronomy, the Hills cloud (also called the inner Oort cloud and inner cloud) is a theoretical vast circumstellar disc, interior to the Oort cloud, whose outer border would be located at around 20,000 to 30,000 astronomical units (AU) fr ...

, but other scientists like

California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...

's Michael Brown also consider other possibilities, including the theory "it may have formed from debris just beyond Neptune n the Kuiper belt">Kuiper_belt.html" ;"title="n the Kuiper belt">n the Kuiper beltand been 'kicked' into its distant orbit by a planet like Neptune or Uranus".

Perturbation

The orbit of currently comes closer to Neptune than any of the other giant planets. More than half of the simulations of this object show that it gets too close to either Uranus or

within the next 180 million years, sending it in a currently unknown direction. This makes it difficult to classify this object as only a

or a

scattered disc The scattered disc (or scattered disk) is a distant circumstellar disc in the Solar System that is sparsely populated by icy small Solar System bodies, which are a subset of the broader family of trans-Neptunian objects. The scattered-disc obj ...

object. The

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Funct ...

, which officially catalogues all trans-Neptunian objects, lists centaurs and SDOs together. is another such object that blurs the two categories. ;Baricentric orbital elements: * aphelion (Q) = 1570 AU (Heliocentric 2006 AU) * semimajor =736.67 AU (Heliocentric 1015 AU) * period = 22,466 yr (Heliocentric 32,347 yr) Given the extreme

orbital eccentricity In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values be ...

of this object, different

epochs In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

can generate quite different heliocentric unperturbed two-body best-fit solutions to the aphelion distance (maximum distance) of this object. With a 2005 epoch the object had an approximate period of about 22,000 years with aphelion at 1557 AU. But using a 2011 epoch shows a period of about 32,000 years with aphelion at 2006 AU. For objects at such high eccentricity, the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

barycentric coordinates In geometry, a barycentric coordinate system is a coordinate system in which the location of a point is specified by reference to a simplex (a triangle for points in a plane, a tetrahedron for points in three-dimensional space, etc.). The bar ...

are more stable than heliocentric coordinates. Using

JPL Horizons JPL Horizons On-Line Ephemeris System provides access to key Solar System data and flexible production of highly accurate ephemerides for Solar System objects. Osculating elements at a given epoch (such as produced by the JPL Small-Body Datab ...

with an observed orbital arc of only 2.9 years, the barycentric orbital elements for epoch 2008-May-14 generate a

of 796 AU and a period of 22,466 years.

Comparison

Notes

Solution using the Solar System
Barycenter In astronomy, the barycenter (or barycentre; ) is the center of mass of two or more bodies that orbit one another and is the point about which the bodies orbit. A barycenter is a dynamical point, not a physical object. It is an important con ...
Read
osculating orbit In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space at a given moment in time is the gravitational Kepler orbit (i.e. an elliptic or other conic one) that it would have around its central body if pertur ...
for more details about heliocentric unperturbed two-body solutions

References

External links