def mc_eta_to_m12(mc, eta):
    """
    Convert chirp mass and symmetric mass ratio to component masses.

    Input: mc - chirp mass
    eta - symmetric mass ratio
    Return: m1, m2 - primary and secondary masses, m1>m2
    """
    m1 = mc / eta ** 0.6 * (1 + (1 - 4 * eta) ** 0.5) / 2
    m2 = mc / eta ** 0.6 * (1 - (1 - 4 * eta) ** 0.5) / 2
    return m1, m2