def term_B(T0, P0, K):
    """Term B in the main equation.
    
    T0 is the temperature (in Kelvin),
    P0 is the pressure (in hPa),
    K is the K term  (see below)."""
    return 1.084e-8 * P0*T0*K + 4.734e-8 * P0**2/T0 * 2/(3 - 1/K)