Standing solitary waves as transitions to spiral structures in gravitationally unstable accretion disks

Abstract

Astrophysical disks that are sufficiently cold and dense are linearly unstable to the formation of axisymmetric rings as a result of the disk's gravity. In practice, spiral structures are formed, which may in turn produce bound fragments. We study a nonlinear dynamical path that can explain the development of spirals in a local model of a gaseous disk on the subcritical side of the gravitational instability bifurcation. Axisymmetric equilibria can be radially periodic or localized, in the form of standing solitary waves. The solitary solutions have an energy slightly larger than a smooth disk. They are further unstable to non-axisymmetric perturbations with a wide range of azimuthal wavenumbers. The solitary waves may act as a pathway to spirals and fragmentation.

6 pages, 4 figures, ApJL accepted

References in corpus (5)

• Athena: A New Code for Astrophysical MHD
• Convergence of the critical cooling rate for protoplanetary disk fragmentation achieved; the key role of numerical dissipation of angular momentum
• Formation of intermediate-mass planets via magnetically-controlled disk fragmentation
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Cited by in corpus (2)

• Characterizing fragmentation and sub-Jovian clump properties in magnetized young protoplanetary disks
• Nonlinear analysis of gravitational instability in a 3D gaseous disc