def mass_loss_loon05(L,Teff):
    ''' 
    mass loss rate van Loon etal (2005).

    Parameters
    ----------
    L : float
        L in L_sun.
    Teff : float
        Teff in K.
        
    Returns
    -------
    Mdot
        Mdot in Msun/yr
    
    Notes
    -----
    ref: van Loon etal 2005, A&A 438, 273
    
    '''
    
    Mdot = -5.65 + np.log10(old_div(L,10.**4)) -6.3*np.log10(old_div(Teff,3500.))
    return Mdot