Wikipedia:Today's featured article/November 14, 2023
Sedna is a trans-Neptunian object with the asteroid number 90377. It was discovered on November 14, 2003 by astronomers Michael Brown, Chad Trujillo, and David Rabinowitz. Sedna is currently 88 Astronomical units (AU) from the Sun, which is three times the distance between Neptune and the Sun. Sedna's orbit is an ellipse and its aphelion is estimated to be 937 AU. For most of its orbital period, Sedna is farther from the Sun than any known dwarf planet candidate and most comets. Sedna is one of the reddest objects in the solar system. It is mostly composed of water, methane, nitrogen ice, and tholin. It may be located within the same open cluster where the Sun was born, some astronomers suggest that Sedna is a celestial body captured by the Sun from another star system. Michael Brown considers it the most important trans-Neptunian object ever discovered, because its unusual orbit may yield information about the origin and early evolution of the Solar System. (Full article...)