Approximate lifetime of stars located on the main sequence
==========================================================

The main sequence is the stage of stellar evolution. This stage begins in stars after the
protostar stage. At the beginning of the main sequence stage, the age of the star is
considered to be zero. It is possible to calculate the time spent on the main sequence
for a star by knowing such a time for the Sun, as well as the mass and luminosity of the
Sun and the star.

**Notation:**

#. :math:`L_\odot` (:code:`L_Sun`) is :attr:`~symplyphysics.quantities.sun_luminosity`.
#. :math:`M_\odot` (:code:`M_Sun`) is :attr:`~symplyphysics.quantities.solar_mass`.

**Links:**

#. `Wikipedia, second formula <https://en.wikipedia.org/wiki/Main_sequence#Lifetime>`__.

.. py:currentmodule:: symplyphysics.laws.astronomy.approximate_time_of_stars_location_on_the_main_sequence

.. py:data:: lifetime

    Lifetime (:attr:`~symplyphysics.symbols.basic.time`) of the star on the main sequence.

Symbol:
    :code:`t`

Latex:
    :math:`t`

Dimension:
    :code:`time`


.. py:data:: star_mass

    :attr:`~symplyphysics.symbols.basic.mass` of the star.

Symbol:
    :code:`m`

Latex:
    :math:`m`

Dimension:
    :code:`mass`


.. py:data:: star_luminosity

    :attr:`~symplyphysics.symbols.astronomy.luminosity` of the star.

Symbol:
    :code:`L`

Latex:
    :math:`L`

Dimension:
    :code:`power`


.. py:data:: sun_lifetime

    Lifetime (:attr:`~symplyphysics.symbols.basic.time`) on time main sequence of the Sun.

Symbol:
    :code:`t_Sun`

Latex:
    :math:`t_\odot`

Dimension:
    :code:`time`


.. py:data:: law

    :code:`t = t_Sun * m / M_Sun * L_Sun / L`


    Latex:
        .. math::
            t = t_\odot \frac{m}{M_\odot} \frac{L_\odot}{L}