What are planets like Sedna called, dwarf planets, extra solar planets, i'm a little confused?

Answer 1

http://en.wikipedia.org/wiki/Dwarf_planet

at this time, Sedna is not a planet or dwarf planet. the three dwarf planets in this solar system are 1 Ceres, 134340 Pluto, and 136199 Eris. there are many other bodies in the solar system which may be dwarf planets, but astronomers do not know enuff about them to classify them. Sedna is one of these dwarf planet candidates.

the definition of "planet" is not yet settled, however. many astronomers are not satisfied that this new definition is rigorous enuff. i can accept that the definition is flawed, but i have been waiting since i was about ten for astronomers to stop calling 134340 Pluto a planet.

http://en.wikipedia.org/wiki/Extrasolar_planet

extrasolar planets are planets that orbit stars other than the Sun.

http://en.wikipedia.org/wiki/Rogue_planet

rogue or interstellar planets are planetary-mass bodies which are unbound to any star.

Answer 2

Sedna is smaller than a dwarf planet and since it orbits out Sun it is not an extra solar planet. So Sedna is just an asteroid, or Kuiper belt object, or trans Neptunian object.

Answer 3

The latest definition of planet is:
1) It orbits the Sun
2) It has enough mass to have a round shape
3) It has absorbed most of the matter in the neighborhood around its orbit.

Under this definition, there are eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

But there are several, maybe hundreds, of objects which meet the first two criteria but not the third. These are called dwarf planets. Pluto, which was formerly called a planet, turned out to be part of the Kuiper Belt, a cloud of many icy bodies outside the orbit of Neptune. So Pluto has been demoted to dwarf planet. Another dwarf planet is Ceres, the largest body in the asteroid belt between Mars and Jupiter. It used to be called an asteroid, but now its been promoted to dwarf planet.

Extra solar planets are planets that have been detected in orbit around other stars. So they meet the second and third criteria but not the first. They are not a part of our solar system.

Answer 4

large objects inside the kiper belt are called dwarf planets. anything outside the belt that has planet like charateristics are called extrasolar. sedna is inside the belt.