![]() The astronomers used the Spitzer telescope to probe the material that radiates in infrared light. Sankrit and Blair also compared their Hubble observations with those taken with ground-based telescopes to obtain a more accurate distance to the supernova remnant of about 13,000 light-years. These filaments reveal where the shock wave is encountering lower-density, more uniform interstellar material. The Hubble data also show thin filaments of gas that look like rippled sheets seen edge-on. This clumping process is similar to the patterns made by oil and vinegar (a mix of two liquids of different densities) in a shaken bottle of salad dressing. As the shock plows into material lost from the progenitor star, instabilities left in its wake cause the swept-up gas to fragment into clumps. The bright glowing knots are dense clumps that form behind the shock wave. Visible-light images from the Hubble telescope's Advanced Camera for Surveys reveal where the supernova shock wave is slamming into the densest regions of surrounding gas. The stellar ejecta from the explosion initially trails behind the shock wave but eventually catches up with the inner edge of the shell and is heated to X-ray temperatures. In certain cases, the surrounding regions include material shed by the progenitor star in a stellar wind before the explosion, in earlier phases of its evolution. This wave spreads out into surrounding space, sweeping up any tenuous interstellar gas and dust into an expanding shell. ![]() The blast rips the star apart and unleashes a roughly spherical shock wave that expands outward at more than 22 million miles per hour (10,000 kilometers per second), like an interstellar tsunami. The explosion of a star is a catastrophic event. "A range of observations is needed to help us understand the complex relationship that exists among the various components." "For instance, the infrared data are dominated by heated interstellar dust, while optical and X-ray observations sample different temperatures of gas," added Blair, a research professor in the Physics and Astronomy Department at Johns Hopkins, and the lead astronomer on the Spitzer observations. Each component shows up best at different wavelengths." "The glow from young remnants, such as Kepler's supernova remnant, comes from several components. "Multiwavelength studies are absolutely essential for putting together a complete picture of how supernova remnants evolve," said Sankrit, an associate research scientist in the Center for Astrophysical Sciences at Johns Hopkins and the lead astronomer on the Hubble observations. Observations from each telescope highlight distinct features of the supernova remnant, a fast-moving shell of iron-rich material from the exploded star, surrounded by an expanding shock wave that is sweeping up interstellar gas and dust. The combined image unveils a bubble-shaped shroud of gas and dust that is 14 light-years wide and is expanding at 4 million miles per hour (2,000 kilometers per second). A team of astronomers, led by Ravi Sankrit and William Blair of Johns Hopkins University in Baltimore, Md., are using the Great Observatories to analyze the remains, called Kepler's supernova remnant, in infrared radiation, visible light, and X-rays. Modern-day astronomers, on the other hand, have the combined abilities of the Spitzer Space Telescope, the Hubble Space Telescope, and the Chandra X-ray Observatory at their disposal. The telescope would not be invented for another four years. ![]() 9, 1604, observers could use only their eyes to study it. When a new star appeared alongside Jupiter, Mars, and Saturn on Oct. Now, astronomers using NASA's three Great Observatories are unraveling the mysteries of the expanding remains of Kepler's supernova, the last such object seen to explode in our Milky Way galaxy. ![]() ![]() Hubble, Chandra, and Spitzer Unveil Kepler’s Supernovaįour hundred years ago, sky watchers, including the famous astronomer Johannes Kepler, were startled by the sudden appearance of a "new star" in the western sky, rivaling the brilliance of the nearby planets. ![]()
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