Who or what are Eris and Sedna?

Question

I read a question about Pluto, and one of the answers referred to Eris and Sedna. And is there a Xena, as well? What are these, captured debris or really planets in the sense of formed from the sun? So just what is this solar system composed of these days, anyway?

Answer 1

Sedna is a reddish-colored, planet-like body located in the Oort Cloud, approximately 13 billion kilometers (8 billion miles) away (three times farther from Earth than Pluto). Sedna is abour 800-1100 miles in diameter (this is about three-fourths the size of Pluto). Sedna turns on its axis once every 40 days (its day is 40 Earth days long); this is a very slow rotation.

In 2005, astronomers discovered what they thought to be a new planet in the Solar system. The object, which has been named Eris, is currently 97 astronomical units away, putting it more than twice the distance of the dwarf planet Pluto and therefore the farthest visible object in the solar system. Although we cannot yet be sure, we think that Eris is a rocky/icy object about one and a half times the size of Pluto.

On September 30, a team led by Caltech's Michael Brown announced discovery of a moon orbiting the distant body 2003 UB313. The object, discovered in January 2005, appears to be 20-percent larger than Pluto, leading Brown to dub it the tenth planet. The team has given it the unofficial nickname "Xena,"

Answer 2

Quite recently, new bodies have beed found orbiting the Sun beyond Neptune. The first of these was Sedna, a body smaller in size than Pluto. Discovered later was Eris (orignally nicknamed Xena), which turned out to be bigger than Pluto. The discoverers then laid claim to finding the 10th Planet. However, due to the amount of small bodies being found, a new category of bodies was made: Dwarf Planets. Pluto, Sedna and Xena fell under this category thus reducing the Solar System planet count to 8.

Answer 3

The discovery of 2003 UB313 Eris, the 10th planet largest known dwarf planet

sedna is The coldest most distant place known in the solar system

Answer 4

tranzistors