Star Formation Processes versus Planet Formation Processes
  The processes of star formation are fundamentally different from those of planet formation. Since the mass of a very-low-mass object alone doesn't allow us to uniquely determine its basic nature, we have to look at its other characteristics, such as its motion, its age, its atmospheric composition, its internal structure and composition, etc., in order to ascertain its formation mechanism. 
Shiv S. Kumar (1,2)((1)Department of Astronomy, University of   Virginia, Charlottesville, USA (2)The Galileo Institute, Cha...