Explanation:
Are these two supernova shells related?
To help find out, the 8-meter
Gemini Telescope located high atop a mountain in
Chile
was pointed at the unusual, huge, double-lobed cloud dubbed
DEM L316.
The resulting image,
shown above, yields tremendous detail.
Inspection of the image as well as
data taken by the orbiting
Chandra X-Ray Observatory
indicate how different the two
supernova remnants are.
In particular, the smaller shell appears to be the result of
Type Ia supernova
where a white dwarf exploded,
while the larger shell appears to be the result of a
Type II supernova
where a massive normal star exploded.
Since those two stellar types evolve on such
different time scales, they likely did not form together and so are likely not physically associated.
Considering also that no evidence exists that the
shells are colliding,
the two shells are now hypothesized to be superposed by chance.
DEM L316
lies about 160,000
light years
away in the neighboring
Large Magellanic Cloud (LMC) galaxy,
spans about 140 light-years across, and appears toward the southern constellation of the
Swordfish (Dorado).
