Lecture 19 - Three ways energy y is transported a)...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 19 Mechanical properties of stars a) Gravity- holds stars together and makes them circular b) Gas pressure- prevents star from collapsing in on itself i) Boyle’s Law- pressure is proportional to density (blowing up balloon) ii) Charles’ Law- pressure is proportional to temperature (can implosion) iii) Compressing gas causes it to heat up Kinetic Theory of Gases- by James Clerk Maxwell a) “Tiny elastic particles (atoms) in constant motion” b) Allows us to understand i) Random thermal motions create pressure ii) Temperature is a measure of speed (kinetic energy) iii) Explains Charles’ and Boyle’s Law iv) Explains hydrostatic equilibrium Thermal Equilibrium a) Energy flows from hot to cool b) As much heat is flowing into the sun from an underneath layer as heat leaves the surface of it c) Temperature profile of star- determined from condition that temperature at the surface is constant
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Three ways energy y is transported a) Radiation- heat hits you directly b) Conduction- heat transfers or flows along the object being heated c) Convection- circulation of air Opacity a) Level at which matter absorbs radiation b) Sun opacity depends on interior electron scattering c) Opacity in a region determines rate at which energy flows i) If opacity is too large, we get convection Sun convection a) Core radiates the rest of the layers of the sun b) Main transport mechanisms are radiation and convection Mass-Luminosity relationship- by Sir Arthur Eddington a) As mass increases gravity increases and so pressure must increase as well b) Charles law then says that temperature increases which S-B says that luminosity must increase then Why is a star hot? a) Stars radiate because theyre hot b) Why? They have an energy source...
View Full Document

This note was uploaded on 05/03/2011 for the course AST 301 taught by Professor Harvey during the Fall '07 term at University of Texas at Austin.

Page1 / 2

Lecture 19 - Three ways energy y is transported a)...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online