Eclipse of Distant Exoplanet HD 189733b Seen in NASA’s Chandra X-ray Observatory Pictures

NASA announced that is has images of the first eclipse of another planet outside of our solar system. The eclipse of this ‘exoplanet’ was seen by the Chandra X-ray Observatory and marks the first time, since exoplanets were discovered almost 20 years ago, that an exoplanet has been seen passing in front of its parent star.

NASA sites an advantageous alignment of a planet and its parent star in the system HD 189733, which enabled the Chandra X-ray Observatory and the European Space Agency’s XMM Newton Observatory to observe a dip in X-ray intensity as the planet transited the star. The star system is some 63 light-years from Earth.

“Thousands of planet candidates have been seen to transit in only optical light,” said Katja Poppenhaeger of Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., who led a new study to be published in the Aug. 10 edition of The Astrophysical Journal. “Finally being able to study one in X-rays is important because it reveals new information about the properties of an exoplanet.”

Similar in size to our Jupiter, HD 189733b, orbits very close to its star. At about 30 times closer to its star than Earth is to the sun, HD 189733b would be very hot. At this close range, the exoplanet orbits the parent star once every 2.2 days.

Using the Kepler telescope, NASA has studied images of HD 189733b at optical wavelengths, and determined that the planet is blue in color. They believe that the color is a result, not of water, but instead the preferential scattering of blue light by silicate particles in its atmosphere.