Chandra finds oxygen ring in ashes of exploded star | 28/09/1999 | ||
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This X-ray image of the supernova remnant E0102-72 shows an expanding multimillion degree ring of oxygen that was created deep inside a massive star and hurled into space by the explosion of the star. The ring is about 30 light years across and contains more than a billion times the oxygen contained in the Earth's ocean and atmosphere. | ||
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Image Credit: NASA/MIT | |||
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This X-ray image of the supernova remnant E0102-72 shows an expanding multimillion
degree ring of oxygen and neon that was created deep inside a massive star
and hurled into space by the explosion of the star. The ring is about 30
light years across and contains more than a billion times the oxygen contained
in the Earth's ocean and atmosphere. Images such as these provide unprecedented
details about the creation and dispersal of heavy elements necessary to
form planets like Earth.
E0102-72 is the remnant of a supernova explosion located in our neighbor galaxy, the Small Magellanic Cloud, nearly 200,000 light years away. It was created by the explosion of a star that was more than ten times as massive as our Sun. We are seeing the aftermath of the explosion a thousand or more years after the outburst. Shock waves are heating gas to temperatures of nearly 10 million degrees, so it glows with X-rays that are detected by Chandra's instruments By using the High Energy Transmission Grating Spectrometer (HETG), astronomers were able to pinpoint the distribution of each chemical element individually and measure the velocities of different parts of the expanding ring. They also show the shock wave in a kind of "freeze-frame," revealing the progressive heating of the stellar matter as it plows into the surrounding gas. This is the first time such detailed X-ray information has ever been obtained for a supernova remnant, and should provide critical clues to the nature of supernovae. |
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The grating spectrometer, which was built by an MIT team led by Canizares,
spreads the X-rays according to their wavelength, giving distinct images
of the object at specific wavelengths characteristic of each chemical element.
Small wavelength shifts caused by the Doppler effect are used to measure
the expansion velocities of each element independently.
Most of the oxygen in the universe, for example, is synthesized in the interiors of relatively few massive stars like the one being studied here. When they explode, they expel the newly manufactured elements which become part of the raw material for new stars and planets. The amount of oxygen in the E0102-72 ring is enough for thousands of solar systems. By measuring the expansion velocity of the ring, the team can estimate the amount of energy liberated in the explosion. The expansion energy would be enough to power the sun for 3 billion years. The ring has more complex structure and motion than can be explained by current simplified theories, suggesting complexity in the explosion itself or in the surrounding interstellar matter. |
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