Discovery of a new planet in the outer solar system

A team of researchers from the California Institute of Technology in Pasadena, CA, Yale University in New Haven, CT, and Gemini Observatory in Hilo, HI, report the discovery of a new planet in the outer solar system. Officially designated 2003 UB313, the new planet is intrinsically brighter than Pluto and three times farther away. Assuming the reflectivity of the surface is the same as Pluto’s, it is the largest object detected in the solar system since the discovery of Neptune and its moon Triton in 1846.

The discovery team consists of Michael Brown at Caltech, David Rabinowitz at Yale, and Chad Trujillo at the Gemini Observatory. This is the same team that a year ago announced their discovery of Sedna, a smaller body also at the distant edges of our solar system. The team has since discovered several other Pluto-scale bodies including 2005 FY9 and 2003 EL61, both objects in the outer solar system comparable in size to Pluto but smaller. 2003 EL61 was independently discovered by Spanish astronomers and reported today.

All of the new discoveries have been made with the Palomar QUEST camera, a gigantic digital camera built at Yale University and mounted on the 48-inch-diameter telescope at the Palomar Observatory in California. With this camera, observers can search the entire northern sky multiple times with greater sensitivity than any other telescope in the world. The Palomar Quest camera is currently being used by researchers at Yale, Caltech, and the University of California at Berkeley to search not only for new planets, but also for supernovae, distant galaxies, and variable stars.

2003 UB313 is currently about 100 times farther from the Sun than the Earth. The orbital period is close to 560 years. In 280 years, it will be at its closest point, 38 times farther from the Sun than the Earth. The discovery team is currently using the Keck and Gemini Telescopes in Hawaii, NASA’s Spitzer Space Telescope, and smaller telescopes in Chile to measure the color, reflectivity, composition, rotation rate, and other properties of 2003 UB313. The observations from Chile already reveal a neutral, grey color typical of large icy bodies in the outer solar system. Observations of the reflected light at infrared wavelengths made with the Gemini telescope reveal the presence of frozen water, methane, and other gasses prevalent in the atmospheres of the outer planets.

The Palomar camera, which has over 160 million pixels and 112 CCD detectors, was built for the 48″ Palomar telescope by Charles Baltay, Professor of Applied Physics and Astronomy at Yale University. Other members of the construction team at Yale were David Rabinowitz, William Emmet, Tom Hurteau, Nancy Ellman, and Rochelle Lauer. The electronics were designed at Indiana University by Professor James Musser, Mark Gebhard, and Brice Adams.