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2003 UB313 - Discovery

2003 UB313 - Discovery: Encyclopedia II - 2003 UB313 - Discovery

2003 UB313 was discovered by the team of Michael Brown, Chad Trujillo, and David Rabinowitz on January 5, 2005 from images taken on October 21, 2003, and the discovery was announced on July 29, 2005, the same day as two other large TNOs, 2003 EL61 and 2005 FY9. The search team has been systematically scanning for large outer solar system bodies for several years, and had previously been involved in the discovery of several other very large trans-Neptunian objects, including 500 ...

2003 UB313: Encyclopedia II - 2003 UB313 - Discovery

2003 UB313 - Discovery

2003 UB₃₁₃ was discovered by the team of Michael Brown, Chad Trujillo, and David Rabinowitz on January 5, 2005 from images taken on October 21, 2003, and the discovery was announced on July 29, 2005, the same day as two other large TNOs, 2003 EL₆₁ and 2005 FY₉. The search team has been systematically scanning for large outer solar system bodies for several years, and had previously been involved in the discovery of several other very large trans-Neptunian objects, including 50000 Quaoar, 90482 Orcus, and 90377 Sedna.

Routine observations were taken by the team on October 21, 2003 using the 48-inch Samuel Oschin reflecting telescope at Mount Palomar Observatory, California, but the object captured on the images was not discovered at that point due to its very slow motion across the sky: the team's automatic image searching software excluded all objects moving at less than 1.5 arcseconds per hour to reduce the number of false positives returned. However, when 90377 Sedna was discovered it was moving at 1.75 arcsec/hour, and in light of that the team decided to reanalyze their old data with a lower limit on the angular motion, sorting through the false positives by eye. In January 2005, this re-analysis revealed 2003 UB₃₁₃'s slow motion against the background stars.

Follow-up observations were then carried out to make a preliminary determination of its orbit, which allowed its distance and size to be estimated. The team had planned to delay announcing their discovery until further observations had been made which would have allowed more accurate determinations of the body's size and mass, but were forced to bring forward the announcement when the discovery of another object they had been tracking (2003 EL₆₁) was announced by another group in Spain. Brown's group later accused the Spanish group of a serious breach of ethics in connection with the discovery of 2003 EL₆₁ and asked that they be stripped of credit for its discovery (see the 2003 EL₆₁ or Michael E. Brown articles for details).

Yet more observations released in October 2005 revealed that the object had a moon, S/2005 (2003 UB₃₁₃) 1, nicknamed "Gabrielle." Scientists plan to use this information to determine the mass of 2003 UB₃₁₃.