X-Ray Observations Used to Detect Exoplanet Passing in Front of its Parent Star

Posted on July 29, 2013

HD 189733b hot jupiter


The graphic above depicts HD 189733b, the first exoplanet caught passing in front of its parent star in X-rays. NASA's Chandra X-ray Observatory and the European Space Agency's XMM Newton Observatory were used to observe a dip in X-ray intensity as HD 189733b transits its parent star. This is the first time X-ray observations have detected an exoplanet passing in front of its parent star. The research team used Chandra to observe six transits and data from XMM Newton observations of one.

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

The planet, known as HD 189733b, is a hot Jupiter, meaning it is similar in size to Jupiter in our solar system but in very close orbit around its star. HD 189733b is more than 30 times closer to its star than Earth is to the sun. It orbits the star once every 2.2 days. HD 189733b is the closest hot Jupiter to Earth.

You can see a larger version of the above image here.

Image: X-ray: NASA/CXC/SAO/K.Poppenhaeger et al; Illustration: NASA/CXC/M.Weiss