S2 - Stability and collapse of molecular clouds Flashcards
1
Q
What is free-fall time?
A
The duration of gravitational collapse.
2
Q
What is hydrostatic equilibrium?
A
When the self-gravitational force of a body is balanced by its thermal pressure.
3
Q
What is Jeans mass?
A
The mass of a molecular cloud above which we expect it to collapse.
4
Q
What is isothermal collapse?
A
When gravitational potential energy released during the collapse is radiated away so it does not heat the cloud. Temperature of cloud remains constant during isothermal collapse.
5
Q
How is free-fall time related to density and initial radius?
A
t ∝ n^-1/2
The free-fall time is longer for less dense regions, and shorter for denser regions.
Free-fall time is independent of initial radius. So, no relation.
