vice.milkyway.Z_solar
=====================

Type : real number

Default : 0.014

The metallicity by mass of the sun :math:`M_Z/M_\odot`. This is used
in calibrating the total metallicity of the interstellar medium (ISM),
which is necessary when there are only a few elements tracked by the
simulation with metallicity dependent yields. This scaling is
implemented as follows:

.. math:: Z_\text{ISM} = Z_\odot \left[\sum_i Z_i\right]
	\left[\sum_i Z_i^\odot\right]^{-1}

where the summation is taken over all elements tracked by the
simulation.

.. note::

	The default value is the metallicity calculated by Asplund et al.
	(2009) [1]_; VICE by default adopts the Asplund et al. (2009)
	measurements on their element-by-element basis in calculating [X/H]
	and [X/Y] in simulations. Users who wish to adopt a different model
	for the composition of the sun should modify **both** this value
	**and** the element-by-element entires in ``vice.solar_z``.

Example Code
------------
>>> import vice
>>> mw = vice.milkyway(name = "example")
>>> mw.Z_solar = 0.014

.. [1] Asplund et al. (2009), ARA&A, 47, 481