A Modification To The Gaseous Pressure Gradients In Spherical Objects: Effects Of The Thermal Motion

The atmosphere pressure gradients of spherical objects are extremely important in astrophysics and other related fields. The classical form of the gradient in a gravitation-dominated object has been widely adopted for quit a long time. But, in this form, a factor has been neglected: the “centrifugal force” that due to the thermal motion of gaseous particles in a special (not parallel) force field. There is sometimes a non-negligible effect on the gaseous pressure gradient by this supposed but really existing “force”. Subject headings: spherical object: pressure gradient, factor: thermal motion It is well known that, in a spherical object, the total force density FR in the radial direction is the reason that causes a gaseous pressure gradient along the radius R (Landau & Lifshitz 1980): dp dR = −FR (1) The force density FR is the summation of radial force densities, which is possibly owing to different causes, e.g., the gravity, the magnetic tension and the centrifugal force for the object rotation. The classical form of the atmosphere pressure gradient in a spherical object, such as the star and the planet, is often gravitation-dominated and expressed as: FR = GM R ρ, where M is the total mass of the central object and ρ is the mass density of the gas. While in the accretion disk, the centrifugal force is also important even able to approach a comparable level of the central gravity. By all these possible causes, the engendered pressure gradient is very important in statics and dynamics of celestial bodies as shown in astrophysics. In this paper, an additional factor to the pressure gradient is introduced: the supposed centrifugal force due to the thermal motion of gaseous particles. In the spherical object, the Email: li − [email protected].