Dioretsa (icon ) is a centaur discovered in 1999 notable for its unusual orbit

Orbit

In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...

, which is highly eccentric and retrograde. Its name is the word 'asteroid' spelled backwards to reflect this fact. It is one of twenty or so known minor planets in the Solar System that have a retrograde orbit—see the List of notable asteroids.

Dioretsa's orbit is otherwise similar to a comet

Comet

A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...

's; it has a perihelion of 2.4 AU

Astronomical unit

An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

 and an aphelion of 45.3 AU. This has led to speculation that Dioretsa was originally an object from the Oort cloud

Oort cloud

The Oort cloud , or the Öpik–Oort cloud , is a hypothesized spherical cloud of comets which may lie roughly 50,000 AU, or nearly a light-year, from the Sun. This places the cloud at nearly a quarter of the distance to Proxima Centauri, the nearest star to the Sun...

.