 Although stellar parameters can be expressed in SI units or CGS units , it is often most convenient to express mass , luminosity , and radii in solar units , based on the characteristics of the Sun : 
 Although stellar parameters can be expressed in SI units or CGS units , it <a href='drop_aux' title='1'><mark>is</mark></a>often most convenient to express mass , luminosity , and radii in solar units , based on the characteristics of the Sun : 
Although stellar parameters can b expressed in SI units or CGS units , it often most convenient to express mass , luminosity , and radii in solar units , based on the characteristics of the Sun :