66652 Borasisi provisionally known as , is a trans-Neptunian object

Trans-Neptunian object

A trans-Neptunian object is any minor planet in the Solar System that orbits the Sun at a greater distance on average than Neptune.The first trans-Neptunian object to be discovered was Pluto in 1930...

 (TNO) discovered in 1999 by A. Trujillo, J. Luu and D. Jewitt

David C. Jewitt

David C. Jewitt is a professor of astronomy formerly at the University of Hawaii Institute for Astronomy, now at UCLA. He was born in 1958 in England, and is a 1979 graduate of the University of London. Jewitt received an M.Sc. and a Ph.D. in astronomy at the California Institute of Technology in...

 and identified as binary

Binary asteroid

A binary asteroid is a system of two asteroids orbiting their common center of mass, in analogy with binary stars. 243 Ida was the first binary asteroid to be identified when the Galileo spacecraft did a flyby in 1993...

 in 2003 by K. Noll et al. using the Hubble Telescope.

Satellite

66652 Borasisi is a binary

Binary asteroid

A binary asteroid is a system of two asteroids orbiting their common center of mass, in analogy with binary stars. 243 Ida was the first binary asteroid to be identified when the Galileo spacecraft did a flyby in 1993...

 with the components of comparable size orbiting the barycentre on a moderately elliptical orbit.

The companion (66652) Borasisi I, named Pabu (ˈ) orbits its primary in 46.26 days on an orbit with semi-major axis

Semi-major axis

The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape...

 of 4660 ±170 km and eccentricity

Orbital eccentricity

The orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...

0.460 ±0.013.

External links

• Orbital simulation from JPL (Java)
• Ephemeris
• IAUC 8143