How Do Planets Form?

In the past half-decade, we’ve learned about thousands of planets throughout the galaxy, but we still don’t really know what turns young, spinning baby stars into stable solar systems. In fact, scientists hold two conflicting theories of planetary formation. In one, the enormous discs that surround baby stars collide and accrete into planet-sized objects; in the other, gravitational instabilities in a star’s surrounding nebula cause new planets to clump their way into existence.

But these theoretical efforts are hampered by a real limitation: We don’t have many examples of baby planets to look at.

An international team of astrophysicists is helping to change that. On Thursday, the researchers announced evidence of a second planet orbiting HD100546, a still-young star much larger than our sun. The baby planet seems to be a gas giant, and it orbits its star a little farther than Saturn orbits ours.

This is the second proto-planet that Brittain’s team discovered orbiting HD100546. They detected the first, also a gas giant, last year, which marked “the first time [we saw] a planet forming inside its natal environment.”


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http://www.theatlantic.com/technology/archive/2014/09/how-do-planets-form/379596/