CONAN.utils.aR_to_rho
=====================

.. py:function:: CONAN.utils.aR_to_rho(P, aR, e=0, w=90, qm=0)

   Compute the transit derived stellar density from the planet period and scaled semi major axis.
   uses eqn 39 of kipping 2010 https://doi.org/10.1111/j.1365-2966.2010.16894.x to account for eccentricity


   :param P: The planet period in days
   :type P: float, ufloat, array-like;
   :param aR: The scaled semi-major axis of the planet orbit
   :type aR: float, ufloat, array-like;
   :param e: The eccentricity of the orbit. Default is 0
   :type e: float, ufloat, array-like;
   :param w: The argument of periastron in degrees. Default is 90
   :type w: float, ufloat, array-like;
   :param qm: The mass ratio of the planet to the star. Default is 0 (Mp<<Ms)
   :type qm: float, ufloat, array-like;

   :returns: **rho** -- The stellar density in g/cm^3
   :rtype: array-like;