CONAN.utils.rho_to_aR
=====================

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

   convert stellar density to semi-major axis of planet with a particular period.
   uses eqn 39 of kipping 2010 https://doi.org/10.1111/j.1365-2966.2010.16894.x to account for eccentricity

   :param rho: The density of the star in g/cm^3.
   :type rho: float, ufloat, array-like;
   :param P: The period of the planet in days.
   :type P: 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: **aR** -- The scaled semi-major axis of the planet.
   :rtype: array-like;