Planet discovery: Color comes from "blow-torched atmosphere"

This illustration from the European Space Agency (ESA) is an artists impression of HD 189733B.
AP Photo/ESA-Hubble, M. Kornmesser

LONDON Astronomers have for the first time managed to determine the color of a planet outside our solar system, a blue gas giant some 63 light years away.

An international team of astronomers working with the Hubble Telescope made the discovery observing HD 189733B, one of Earth's nearest planets outside the solar system.

Frederic Pont of the University of Exeter in England said Friday that "measuring the planet's color is a real first -- we have never managed it before with a planet outside our own solar system."

To ascertain the planet's color the astronomers measured the amount of light reflected off its surface as it eclipsed its host star. While the planet's color may seem to resemble Earth, that is where the similarities end.

"The daytime temperature is nearly 2,000 degrees Fahrenheit, and it possibly rains glass -- sideways -- in howling, 4,500-mph winds. The cobalt blue color comes not from the reflection of a tropical ocean as it does on Earth, but rather a hazy, blow-torched atmosphere containing high clouds laced with silicate particles," NASA said in a statement.

HD 189733B belongs to a class of "hot Jupiters" and has an atmosphere temperature of around 1,000 degrees Celsius. These planets orbit very close to their parent stars. Researchers are hoping that the HD 189733b discovery will bring on new insights into the chemical composition of this entire class of planets.