What is the source of centripetal force that a planet requires to revolve around the Sun?

Gravitational force is the source of centripetal force that a planet requires to revolve around the Sun.
This force depends on the product of the masses of the planet and the sun and the distance between them and is given as:
$\mathrm{F} = \frac{{\mathrm{GM}}_1{\mathrm{M}}_2}{{\mathrm{R}}^2}$

Here, G is the gravitational constant;  M₁ and  M₂ are the masses of the objects; R is a separation between the objects.

Gravity is the centripetal force that keeps planets moving around the Sun, and satellites moving around planets.