Authored by : Dr. Harold Alden WilliamsMontgomery College at the Takoma Park/Silver Spring Campus,

Planetarium Director and Physics and Geology Laboratory Coordinator

The Physics of Star Formation

The Physics of Star Formation

A few important equations in Newtonian

hydrodynamics• Continuity equation, conservation of mass

• Equation of Motion, force/volume, in the fluid continuum

• Energy Equation

• Equation of State

• Newtonian Gravity, Poisson’s Equation

Equation of Continuity, conservation of mass

where is the mass density, is the time, is the fluid velocity.

Newton’s Second Law,conservation of momentum

written here in per unit volume.

is the fluid velocity, is the time, is the force per unit volume, is the pressure, is the gravitational potential.

Relationship between total derivative with respect to time and partial derivatives with respect to time for any

function g(x;t)

Newton’s Second Law,conservation of momentum

in conservative form using previous equation

Where is the mass density, is the fluid velocity, is the time, is the momentum density is the pressure, is the gravitational potential.

TextText

Energy EquationThe Energy Equation is the internal energy density

is the velocity

is the pressure

is the local heating functions

is the local cooling function

is the thermal conductivity

is the temperature

Three ways to do science

1. Observation or Experiments, requires large expensive telescopes and/or research grants, doable with graduate student helpers.

2. Theory, largely algebra and calculus, cheap, doable in an undergraduate institution even a community college.

3. Simulation, solving equations on a computer at a super computers center, doable with graduate student helpers in a few institutions with super computer centers.