is a binary

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 a semi-major axis of 30.1 astronomical units (au). Typically, ...

from the

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 objec ...

in the outermost regions 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 "Solar S ...

. It was discovered by Arianna Gleason in 1995 and measures approximately 176 kilometers in diameter. Its 80-kilometer

minor-planet moon A minor-planet moon is an astronomical object that orbits a minor planet as its natural satellite. , there are 457 minor planets known or suspected to have moons. Discoveries of minor-planet moons (and binary objects, in general) are important ...

, provisionally designated , was discovered on 9 November 2002.

Discovery

was discovered on 15 October 1995, by American astronomer Arianna Gleason as part of UA's

Spacewatch The Spacewatch Project is an astronomical survey that specializes in the study of minor planets, including various types of asteroids and comets at University of Arizona telescopes on Kitt Peak near Tucson, Arizona, in the United States. The Sp ...

survey at

Kitt Peak National Observatory The Kitt Peak National Observatory (KPNO) is a United States astronomy, astronomical observatory located on Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono Oʼodham Nation, west-southwest of Tucson, Arizona. With ...

, near Tucson, Arizona. It was the first of the bodies presently classified as a

scattered-disc object 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 objec ...

(SDO) to be discovered, preceding the SDO prototype by almost a year.

Satellite

A companion was discovered by Denise C. Stephens and Keith S. Noll, from observations with the

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...

taken on 9 November 2002, and announced on 5 October 2005. The satellite, designated , is relatively large, having a likely mass of about 10% of the primary. Its orbit has not been determined, but it was at a separation of only about to the primary at the time of discovery, with a possible orbital period of about half a day and an estimated diameter of . 1995 TL8 binary-earth comparison

Scattered–extended object

is classified as

detached object Detached objects are a dynamical class of minor planets in the outer reaches of the Solar System and belong to the broader family of trans-Neptunian objects (TNOs). These objects have orbits whose points of closest approach to the Sun (perihelion ...

(scattered–extended) by the

Deep Ecliptic Survey The Deep Ecliptic Survey (DES) is a project to find Kuiper belt objects (KBOs), using the facilities of the National Optical Astronomy Observatory (NOAO). The principal investigator is Robert L. Millis. Since 1998 through the end of 2003, the sur ...

, since its orbit appears to be beyond significant gravitational

interactions Interaction is action that occurs between two or more objects, with broad use in philosophy and the sciences. It may refer to: Science * Interaction hypothesis, a theory of second language acquisition * Interaction (statistics) * Interactions o ...

with

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

's current orbit. However, if Neptune migrated outward, there would have been a period when Neptune had a higher eccentricity. Simulations made in 2007 show that appears to have less than a 1% chance of being in a 3:7 resonance with Neptune, but it does execute circulations near this resonance.

Numbering and naming

This minor planet was numbered by 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. Function ...

on 20 November 2002. As of 2018, it has not been named.

Notes

References

External links

1999 MPEC listing

Asteroid Lightcurve Database (LCDB)
query form

)

– Minor Planet Center * * {{DEFAULTSORT:1995 TL8 048639 Discoveries by Arianna E. Gleason 048639 19951015 20021109