CONAN.utils.transit_depth
=========================

.. py:function:: CONAN.utils.transit_depth(RpRs, b)

   Calculate the area of overlap between two circles (planet and star) given the impact parameter.
   This gives the expected transit depth (accurate to <0.1ppm)for a planet transiting a uniform intensity star.
   This uses the formula for the area of intersection of two circles. For full overlap, we get RpRs**2.

   :param RpRs: Radius of the planet in units of the star's radius.
   :type RpRs: float,
   :param b: Impact parameter (distance from the center of the star to the center of the planet).
   :type b: float

   :returns: **transit_depth** -- The area of overlap between the two circles, normalized by the area of the star.
   :rtype: float