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Planet X Larger Than Pluto?
nova_planitia writes "The Minor Planet mailing list is buzzing with the discovery by an amateur astronomer of a 17th magnitude object 51 astronomical units from the Sun, tentatively designated 2003 EL61. For those not versed in astronomical lingo, this is an object several times brighter than Pluto even though it is 25% farther out from the Sun (the orbit vizualised by JPL). This means that barring a strangely reflective surface, this object is larger than Pluto, possibly Mars-sized! The debate whether Pluto is a planet is likely to get rekindled by this discovery."
Actually, TFA mentions that astronomers discovered Sedna in 2004, and since this is 2005, this is a separate discovery.
from TFA: "The same team that found Sedna have designated it [the new discovery] K40506A after it was picked up by the Gemini telescope and one of the twin Keck telescopes in Hawaii."
The TFA mentions two teams of scientists who found the object independently of each other. It doesn't say anything about discovery by an amateur astronomer.
Star: Any massive gaseous body emitting more energy due to nuclear fusion then by thermal radiation alone.
Planet: Any body orbiting a star which is roughly spherical due to self-gravitation. (by this definition our solar system has 13 (14 now?) planets including Charon, Ceres, Sedna and Quaoar)
Planetoid: Any body not orbiting a star which is roughly spherical due to self-gravitation. There is conjecture on this one. It once was just a synonym for asteroid, however now many call Ceres, Sedna and Quaoar planitoids or even minor planets, but I don't since they all meet my definition of a planet.
Planetesimal: Any celestial object that does not have suffecient mass to form into a spherical shape. All asteroids and comets are planetesimals.
Protoplanet: Any body in a solar nebula which is roughly spherical due to self-gravitation and does not produce energy by nuclear fusion.
Moon: An object which is roughly spherical due to self-gravitation which orbits a planet. By this definition Phobos and Demos are not moons.
Satellite: An object whose mass is not sufficent to form into a spherical shape which orbits a planet.
Double-Planet: Two Planets of comparable mass orbiting one another in a system orbiting a star, who are both tidally coupled so as to always show the same face to each other in a system with a center of gravity that is not within either body. The center of gravity of the Earth/Moon system is about 2900 km or about 75% of the radius from the center of the Earth. Also, the Earth doesn't always show the same face to the moon. The Earth/Moon system is NOT a double-planet. The Pluto/Charon system is a double planet as they always show the same face to each other and the center of gravity of the Pluto/Charon system does not lay within either body.
See the Pictures of the Flood of '08
There's already an Apollo asteroid named Bacchus.