According to the IAU 2009 System, what is the definitive value for the astronomical unit in meters?

Answer

Exactly $ exttt{149,597,870,700}$ meters.

The International Astronomical Union (IAU) refined the value to be exactly $ exttt{149,597,870,700}$ meters, moving beyond simple averaging to lock down a fundamental constant.

According to the IAU 2009 System, what is the definitive value for the astronomical unit in meters?
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