def compute_lambda_tilde(m1, m2 ,l1 , l2):
    """ Compute Lambda Tilde from masses and tides components
        --------
        m1 = primary mass component [solar masses]
        m2 = secondary mass component [solar masses]
        l1 = primary tidal component [dimensionless]
        l2 = secondary tidal component [dimensionless]
        """
    M       = m1 + m2
    m1_4    = m1**4.
    m2_4    = m2**4.
    M5      = M**5.
    comb1   = m1 + 12.*m2
    comb2   = m2 + 12.*m1
    return (16./13.)*(comb1*m1_4*l1 + comb2*m2_4*l2)/M5