Inside-out dense iron planets probably the result of massive collision

Inside-out dense iron planets probably the result of massive collision

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How violent are the early histories of solar systems? Planets
are built by the collisions of smaller bodies, so a certain amount
of violence is probably unavoidable. Our own Earth-Moon system
seems to have been formed by a smash-up of two planets, while
Uranus seems to have been flipped on its side by a collision, and
Mercury seems to have lost a lot of its material early in its
history. Is this sort of history common as planets form?

Answering these questions requires a detailed understanding of
the planets themselves, knowledge difficult to attain for any solar
system but our own. But now, following up on observations made with
the Kepler space telescope, researchers are suggesting they’ve
found evidence of a smash-up in an exosolar system about 1,750
light years from Earth.

That’s dense

Kepler-107 has a Sun-like star orbited by at least four planets.
The planets are tightly packed around the star, with orbital
periods ranging from three to 14 days. The lengths of the orbits of
neighboring planets can be expressed as simple ratios of integers
(5:2, 3:1, and so on). This creates what are called “resonant
orbits
,” where the periodic alignment of the bodies helps
stabilize and reinforce the orbits. Generally, this is thought to
occur when planets that form further from the star are migrating
inwards towards it; the resonances help balance things out and keep
the planets from continuing on into the star.

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Source: FS – All – Science – News
Inside-out dense iron planets probably the result of massive collision