Icy objects were previously believed to need less mass to attain hydrostatic equilibrium than rocky objects. yields, If we make the assumption that cold dark matter particles have an isotropic velocity distribution, then the same derivation applies to these particles, and their density This qualification means that the object is symmetrically rounded into an ellipsoid shape, where any irregular surface features are due to a relatively thin solid crust.
r
z is Boltzmann's constant and
B ρ This page was last edited on 26 September 2017, at 12:56.
T ρ being the proper distance to the center of the cluster.
We can also use the principle of hydrostatic equilibrium to estimate the velocity dispersion of dark matter in clusters of galaxies.
-equation, which now reads. D (May, 2001).
( T
{\displaystyle k}
{\displaystyle \sigma _{D}^{2}} 2
( g Thus, hydrostatic balance can be regarded as a particularly simple equilibrium solution of the Navier–Stokes equations. The smallest body confirmed to be in hydrostatic equilibrium is the dwarf planet Ceres, which is icy, at 945 km, whereas the largest body known body to have a noticeable deviation from hydrostatic equilibrium is Iapetus (moon) being made of mostly permeable ice and almost no rock [7].
Superficial deviations from perfect equilibrium, such as peaks, valleys, craters, and other irregularities of the crust which are small in scale compared to the body as a whole, are not considered significant for these definitions. ρ
B
{\displaystyle (t,r,\theta ,\phi )} A rotating star in hydrostatic equilibrium is an oblate spheroid up to a certain (critical) angular velocity. D σ
= M k
Instead, it is rather in a strange walnut-like shape due to its unique equatorial ridge.
B
A hydrostatic balance is a particular balance for weighing substances in water. Learn how and when to remove this template message, a dozen or so equilibrium objects confirmed to exist, List of Solar System objects in hydrostatic equilibrium, http://www.ciclops.org/media/sp/2011/6794_16344_0.pdf. s ϕ is dependent on the redshift
[3] For instance, the pressure-gradient force prevents gravity from collapsing Earth's atmosphere into a thin, dense shell, whereas gravity prevents the pressure gradient force from diffusing the atmosphere into space.
This force balance is called a hydrostatic equilibrium.
{\displaystyle T_{B}}
{\displaystyle r} hydrostatic equilibrium (countable and uncountable, plural hydrostatic equilibria) (physics) The state in which a solid or liquid body has relaxed into the shape that it … This page was last changed on 27 May 2017, at 15:48.
/ According to the definition of planet adopted by the International Astronomical Union in 2006, one defining characteristic of planets and dwarf planets is that they are objects that have sufficient gravity to overcome their own rigidity and assume hydrostatic equilibrium.
ρ The baryonic density satisfies the above equation
This occurs when external forces such as gravity are balanced by a pressure-gradient. This occurs when external forces such as gravity are balanced by a pressure-gradient force.
{\displaystyle m_{B}}
However, Mimas is not actually in hydrostatic equilibrium for its current rotation.
, Hydrostatic equilibrium is the current distinguishing criterion between dwarf planets and small Solar System bodies, and has other roles in astrophysics and planetary geology.
= {\displaystyle {\mathcal {L}}_{X}=\Lambda (T_{B})\rho _{B}^{2}} {\displaystyle \rho _{B}(0)/\rho _{M}(0)}