Consider the dispersion relation of a linear spiral density wave perturbation (equation 4.45 in Chapter 3 of the lecture notes). The Toomre's parameter is (V2)²K defined as Q = = 1/2 лGσ。 , where (V2) 1/2 is the root-mean-square turbulent plus thermal velocity, the epicyclic frequency, σ the unperturbed surface density of the disc and G the gravitational constant. If Q = 0.7, for each of the the following values of the radial wavenumber k choose whether the perturbation makes the spiral pattern stable or unstable. k k = II = 2 4 K K 1/2 stable (1/2 stable (V2)1/2 Κ k = (V unstable 2 1/2 ÷ → k = 2. K (V2)1/2 unstable → k = K (V2)1/2 unstable →

College Physics
11th Edition
ISBN:9781305952300
Author:Raymond A. Serway, Chris Vuille
Publisher:Raymond A. Serway, Chris Vuille
Chapter1: Units, Trigonometry. And Vectors
Section: Chapter Questions
Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...
icon
Related questions
Question
Consider the dispersion relation of a linear spiral density wave perturbation (equation 4.45 in Chapter 3 of the lecture notes). The Toomre's parameter is
(V2)²K
defined as Q = =
1/2
лGσ。
,
where (V2) 1/2 is the root-mean-square turbulent plus thermal velocity, the epicyclic frequency, σ the unperturbed surface
density of the disc and G the gravitational constant. If Q = 0.7, for each of the the following values of the radial wavenumber k choose whether the
perturbation makes the spiral pattern stable or unstable.
k
k
=
II
=
2
4
K
K
1/2 stable
(1/2 stable
(V2)1/2
Κ
k = (V unstable
2 1/2
÷
→
k = 2.
K
(V2)1/2
unstable →
k =
K
(V2)1/2
unstable →
Transcribed Image Text:Consider the dispersion relation of a linear spiral density wave perturbation (equation 4.45 in Chapter 3 of the lecture notes). The Toomre's parameter is (V2)²K defined as Q = = 1/2 лGσ。 , where (V2) 1/2 is the root-mean-square turbulent plus thermal velocity, the epicyclic frequency, σ the unperturbed surface density of the disc and G the gravitational constant. If Q = 0.7, for each of the the following values of the radial wavenumber k choose whether the perturbation makes the spiral pattern stable or unstable. k k = II = 2 4 K K 1/2 stable (1/2 stable (V2)1/2 Κ k = (V unstable 2 1/2 ÷ → k = 2. K (V2)1/2 unstable → k = K (V2)1/2 unstable →
Expert Solution
steps

Step by step

Solved in 2 steps

Blurred answer
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
College Physics
College Physics
Physics
ISBN:
9781305952300
Author:
Raymond A. Serway, Chris Vuille
Publisher:
Cengage Learning
University Physics (14th Edition)
University Physics (14th Edition)
Physics
ISBN:
9780133969290
Author:
Hugh D. Young, Roger A. Freedman
Publisher:
PEARSON
Introduction To Quantum Mechanics
Introduction To Quantum Mechanics
Physics
ISBN:
9781107189638
Author:
Griffiths, David J., Schroeter, Darrell F.
Publisher:
Cambridge University Press
Physics for Scientists and Engineers
Physics for Scientists and Engineers
Physics
ISBN:
9781337553278
Author:
Raymond A. Serway, John W. Jewett
Publisher:
Cengage Learning
Lecture- Tutorials for Introductory Astronomy
Lecture- Tutorials for Introductory Astronomy
Physics
ISBN:
9780321820464
Author:
Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina Brissenden
Publisher:
Addison-Wesley
College Physics: A Strategic Approach (4th Editio…
College Physics: A Strategic Approach (4th Editio…
Physics
ISBN:
9780134609034
Author:
Randall D. Knight (Professor Emeritus), Brian Jones, Stuart Field
Publisher:
PEARSON