A Tour of RX J1131-1231

Narrator (April Hobart, CXC): Black holes seem like such mysterious and complicated objects. On one hand, they are, and astronomers have been studying them for decades to learn more. On the other, black holes are actually quite simple. By this, we mean that black holes are defined by just two simple characteristics: their mass and their spin. While astronomers have long been able to measure black hole masses very effectively, determining their spins has been much more difficult. A new result from researchers using data from NASA's Chandra X-ray Observatory and ESA's XMM-Newton takes a step in addressing the spin question. By a lucky alignment, the light from a quasar some 6 billion light years has been magnified and amplified due to an effect called gravitational lensing. This allowed researchers to get detailed information about the amount of X-rays seen at different energies. This, in turn, gave the researchers information about how fast the supermassive black hole at the center of the quasar is spinning. When combined with the spins from other black holes using more indirect methods, astronomers are beginning to better understand just how black holes grow over time across the Universe.

Return to Podcasts

View/Listen
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.

PODCASTS | MAIN MENU