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Messier 10 and Messier 12 - Two globular clusters in the
constellation Ophiuchus in a wide angle view. |
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Object description: The globular cluster Messier
10 lies at a distance of about 14,500 light years from the solar
system. It orbits the Milky Way in an orbit of about 140 million years. Every
53 million years it crosses the plane of the Milky Way. Thereby it slowly moves
away from the solar system
With an apparent diameter of about 20
arcminutes it has a real diameter of about 83 lightyears. It is classified as
type VII according to the Shapley-Sawyer catalog,
its mass is estimated at 200,000 solar masses.
Messier 10 was discovered
by Charles Messier on May 29, 1764 and described as a "nebula without stars in
the belt of Ophiuchus". |
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Messier 12
With about
250,000 solar masses M12 belongs to the larger globular clusters and to the
inner galactic halo. It also lies in the sky in the constellation Ophiuchus,
not far from M 10 and is a slightly larger twin of Messier 10.
With an
apparent diameter of 13 arcminutes, this corresponds to a real diameter of
about 75 light-years at a distance of 16,000 light-years. It is classified as
type IX according to the Shapley-Sawyer catalog.
This means that its member stars are relatively loosely concentrated toward the
center for a globular cluster. Compared to its neighbor Messier 10 (Class VII),
M12 is much less dense towards the central region.
« Click here or the thumbnail to load a large annoted image
and a size comparison to the full moon. |
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