Arbitrary amplitude solitary waves and double layers in an ultra-relativistic degenerate dense dusty plasma

Arbitrary amplitude solitary waves (SWs) and double layers (DLs) in an ultra-relativistic degenerate dense dusty plasma (containing ultra-relativistic degenerate ultra-cold electron fluid, inertial ultra-cold ion fluid, and negatively charged static dust) have been investigated by the pseudo-potential approach. It has been found that for delta = 1 (where S is the ratio of nonlinear wave speed to linear wave phase speed) extremely large amplitude DLs with negative potential exist for p. = 0.537 (where p is the ratio of dust charge density to ion charge density) and SWs with negative potential exist for 1 > mu > 0.537. It is also shown that for 5> 1 only SWs with positive potential exist for 0 ?.. p <0.537, but SWs with positive potential coexist with SWs or DLs with a negative potential for 0.537> p. > 0.851. The implications of our results in some compact astrophysical objects, particularly, in white dwarfs and neutron stars, have been briefly discussed. (C) 2010 Elsevier BA,. All rights reserved.