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DEM L71:
Supernova Origin Revealed
NASA's Chandra X-ray Observatory image (left panel) of the supernova
remnant DEM L71 reveals a hot inner cloud (aqua) of glowing iron and
silicon surrounded by an outer blast wave. This outer blast wave is also
visible at optical wavelengths (right panel). Data from the Chandra
observation show that the central ten-million-degree Celsius cloud is
the remains of a supernova explosion that destroyed a white dwarf star.
DEM L71 presents a textbook example of the double-shock structure
expected to develop when a star explodes and ejects matter at high
speeds into the surrounding interstellar gas. The expanding ejecta drive
an outward-moving shock wave that races ahead of the ejecta into the
interstellar gas (bright outer rim). The pressure behind this shock wave
drives an inward-moving shock wave that heats the ejecta, seen as the
aqua cloud.
The clear separation of the shocked matter and the heated ejecta in the
Chandra image allowed astronomers to determine the mass and composition
of the ejecta. The computed ejected mass was found to be comparable to
the mass of the Sun. This and the X-ray spectrum, which exhibits a high
concentration of iron atoms relative to oxygen and silicon, convincingly
show that the ejecta are the remains of an exploded white dwarf star.
The size and temperature of the remnant indicate that it is several
thousand years old.
Astronomers have identified two major types of supernovas: Type II, in
which a massive star explodes; and Type Ia, in which a white dwarf star
explodes because it has pulled too much material from a nearby companion
star onto itself. If the mass of the white dwarf becomes greater than
about 1.4 times the mass of the Sun, it becomes unstable and is blown
apart in a thermonuclear explosion. This was the case in DEM L71.
One of the major goals of the study of supernova remnants is to
determine the type of supernova explosion. The identification of DEM L71
as the remnant of an exploded white dwarf, or Type Ia supernova,
represents a major step forward in understanding more about the ways in which stars explode.
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Fast Facts for
DEM L71:
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Credit
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X-ray: NASA/CXC/Rutgers/J.Hughes et al; Optical: Rutgers Fabry-Perot
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Scale
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Image is 1.7 arcmin per side
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Category
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Supernovas and Supernova Remnants
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Coordinates
(J2000)
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RA 05h 05m 41.70s | Dec -67º 52' 38.00'' |
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Constellation
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Dorado
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Observation
Date
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January 04, 2000
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Observation
Time
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10 hours
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Obs.
ID
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775
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Color
Code
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X-ray: Energy (Red 0.3-0.7 keV, Green 0.7-1.1 keV, Blue 1.1-4.2 keV); Optical: Intensity
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Instrument
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ACIS
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Distance
Estimate
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160,000 light years (distance to LMC)
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Reference
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J. Hughes, et al. "Iron-rich Ejecta in the Supernova Remnant DEM L71" Astrophysical Journal, 582, L95, 2003 Jan 10.
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Also Known As
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SNR 0505-67.9
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Release Date
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March 12, 2003
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