def transit_duration_range(period, min_radius_hint, max_radius_hint):
    """This figures out the minimum and max transit duration (q) given a period
    and min/max stellar radius hints.

    One can get stellar radii from various places:

    - GAIA distances and luminosities
    - the TESS input catalog
    - isochrone fits

    The equation used is::

        q ~ 0.076 x R**(2/3) x P**(-2/3)

        P = period in days
        R = stellar radius in solar radii

    Parameters
    ----------

    period : float
        The orbital period of the transiting planet.

    min_radius_hint,max_radius_hint : float
        The minimum and maximum radii of the star the planet is orbiting around.

    Returns
    -------

    (min_transit_duration, max_transit_duration) : tuple
        The returned tuple contains the minimum and maximum transit durations
        allowed for the orbital geometry of this planetary system. These can be
        used with the BLS period-search functions in
        :py:mod:`astrobase.periodbase.kbls` or
        :py:mod:`astrobase.periodbase.abls` to refine the period-search to only
        physically possible transit durations.

    """
    return 0.076 * min_radius_hint ** (2.0 / 3.0) * period ** (-2.0 / 3.0
        ), 0.076 * max_radius_hint ** (2.0 / 3.0) * period ** (-2.0 / 3.0)
