USA (QHA) - NASA says U.S. and European space observatories have made the first X-ray observations of an exoplanet passing in front of its parent star, UPI informs. It marks the first X-ray confirmation of such events in the 20 years since exoplanets were first discovered, the space agency reported Monday. “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 ,”- said Katja Poppenhaeger of the Harvard-Smithsonian Center for Astrophysics in Cambridge. An advantageous alignment of a planet and its parent star in the system HD 189733, 63 light-years from Earth, enabled NASA's 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, NASA said. 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 parent star.