A Definition for Giant Planets Based on the Mass-Density Relationship

Understand

We present the mass-density relationship (log M - log rho) for objects with masses ranging from planets (M ~ 0.01 M_Jup) through stars (M > 0.08 M_Sun).

• This relationship shows three distinct regions separated by a change in slope in log M -- log rho plane.
• In particular, objects with masses in the range 0.3 M_Jup to 60 M_Jup follow a tight linear relationship with no distinguishing feature to separate the low mass end (giant planets) from the high mass end (brown dwarfs).
• The distinction between giant planets and brown dwarfs thus seems arbitrary.