Coma Cluster in 60 Seconds

Narrator (April Hobart, CXC): Galaxy clusters are the largest structures in the Universe held together by gravity. Because they are so big, they play a very important role in the Universe. A new result is revealing clues to how these giant structures grow and evolve over time. Astronomers have discovered enormous arms of hot gas in the Coma cluster of galaxies by using Chandra X-ray Observatory and XMM-Newton, another orbiting X-ray observatory run by the European Space Agency. Researchers think that these arms were most likely formed when smaller galaxy clusters had their gas stripped away by the head wind created by the motion of the clusters through the hot gas -- much the same way that the headwind created by a roller coaster blows the hats off riders. By studying these remarkable arms that span over a half a million light years across, astronomers are taking another step toward understanding the past, present, and perhaps future of these colossal objects.

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HD 189733: NASA's Chandra Sees Eclipsing Planet in X-rays for First Time

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Narrator (April Hobart, CXC): HD 189733b: An exoplanet in orbit around a star about 63 light years from Earth. It has been nearly two decades since the first exoplanets – that is, planets around stars other than our Sun – were discovered. Now for the first time, X-ray observations have detected an exoplanet passing in front of its parent star. The observations, made by NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton Observatory, took advantage of the alignment of a planet and its parent star in HD 189733. This alignment enabled the observatories to observe a dip in X-ray intensity as the planet moved in front of, or transited, the star. This technique is the one used so successfully at optical wavelengths by NASA's Kepler telescope. In earlier studies using optical light, astronomers discovered that the main star in the HD 189733 system had what is known as a "hot Jupiter" around it. This means the planet is about the size of Jupiter, but in very close orbit around its star. The planet – that has been named HD 189733b -- is over 30 times closer to its star than Earth is to the Sun, and goes around the star once every 2.2 days. The new X-ray data suggest that this planet has a larger atmosphere than previously thought. This, in turn, may imply that radiation from the parent star is evaporating the atmosphere of HD 189733b more quickly than expected. The results on HD 189733 demonstrate how we need information from many different telescopes that detect different types of light to get a fuller picture of these mysterious worlds that we are now able to explore.

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