20729 (1999 XS143) is a large asteroid that shares Jupiter's orbit around the sun. NASA JPL has not classified 1999 XS143 as potentially hazardous because its orbit does not bring it close to Earth.
1999 XS143 orbits the sun every 4,360 days (11.94 years), coming as close as 4.88 AU and reaching as far as 5.56 AU from the sun. 1999 XS143 is about 51.0 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the U.S. state of Rhode Island.
The rotation of 1999 XS143 has been observed. It completes a rotation on its axis every 5.72 hours.
1999 XS143's orbit is 3.98 AU from Earth's orbit at its closest point. This means that there is an extremely wide berth between this asteroid and Earth at all times.
Orbital simulations conducted by NASA JPL's CNEOS do not show any close approaches to Earth.
1999 XS143's orbit is determined by observations dating back to Feb. 15, 1953. It was last officially observed on April 17, 2023. The IAU Minor Planet Center records 2,478 observations used to determine its orbit.
The position of 20729 (1999 XS143) is indicated by a ◯ pink circle. Note that the object may not be in your current field of view. Use the controls below to adjust position, location, and time.