def calc_teff_ratio_from_flux_rad_ratio(flux_rad_ratio):
    """Calculate ratio of the effective temperatures of the smaller star to greater star
    from the ratios of the radiative fluxes.
    
    Parameters
    ----------
    flux_rad_ratio : float
        Ratio of radiative fluxes of smaller star to greater star.
        flux_rad_ratio = flux_rad_s / flux_rad_g
        
    Returns
    -------
    teff_ratio : float
        Ratio of effective temperatures of smaller-sized star to greater-sized star.
        teff_ratio = teff_s / teff_g

    Notes
    -----
    teff_ratio = teff_s / teff_g
               = flux_rad_ratio**0.25 = (flux_rad_s / flux_rad_g)**0.25
    From equation 7.10, 7.11 in section 7.3 of [1]_
    
    References
    ----------
    .. [1] Carroll and Ostlie, 2007, An Introduction to Modern Astrophysics
    
    """
    teff_ratio = flux_rad_ratio ** 0.25
    return teff_ratio
