spacetoday.net: Most distant exoplanet discovered

Posted: Wed, Jan 8, 2003, 7:47 AM ET (1247 GMT)
Exoplanet OGLE-TR-56b illustration (CfA)

Astronomers announced Monday that they used a different technique to discover the most distant exoplanet found to date. Astronomers from the Harvard-Smithsonian Center for Astrophysics said they found the planet orbiting the star OGLE-TR-56 by observing the planet transit, or cross in front of the star, causing the star to dim on a periodic basis. The star is 5,000 light-years away, about 20 times farther away than any other star where extrasolar planets have been found. The planet, named OGLE-TR-56b, also orbits closer to its star than any other exoplanet, completing one orbit in just 29 hours, which would give the planet a temperature of nearly 2,000 degrees Celsius, hot enough to form clouds of iron. The planet has an estimated mass nine-tenths that of Jupiter, and is likely a gas giant with a density like that of Saturn. The planet was originally identified as part of the Optical Gravitational Lensing Experiment (OGLE), an effort to look for brightening of stars created by gravitational lenses. This discovery is the first time an exoplanet has been discovered by the transit technique, also transits have been used to confirm at least one other exoplanet discovery.