Sgr A* jet in 60 Seconds

Narrator (April Hobart, CXC) Jets of high-energy particles are found throughout the Universe on large and small scales. They are produced by young stars and by giant black holes. Jets play important roles in transporting energy away from the central object and, on a galactic scale, in regulating the rate of formation of new stars.

Because of that, astronomers have been searching for decades for a jet from the Milky Way's black hole known as Sagittarius A*. Over the years, there have been several reports of hints of a jet from Sgr A*, but none was conclusive. A new study involving data from NASA's Chandra X-ray Observatory and the Very Large Array, however, has provided the best case yet for a jet from our Galaxy's supermassive black hole.

One piece of evidence is a straight line of X-rays that points to Sgr A*. Another is the discovery of a shock front - akin to a sonic boom - seen in radio data, where the jet appears to be striking a cloud of gas. By combining these clues with other information, astronomers think they have the strongest evidence to date for a jet blasting out of Sgr A*. The likely discovery of a jet from Sgr A* helps astronomers learn more about the giant black hole, including how it is spinning.

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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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