What is the Magnetic Flux of a White Dwarf Derived from the Sun?

Click For Summary

Homework Help Overview

The discussion revolves around calculating the magnetic flux of a white dwarf derived from the sun's properties, particularly focusing on the sun's rotational period and magnetic flux density. The original poster attempts to relate the sun's characteristics to those of a white dwarf, raising questions about the conservation of momentum and the implications of changing physical dimensions on magnetic flux.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants explore the relationship between the sun's and white dwarf's magnetic flux, questioning whether the flux remains constant during the transition. There are inquiries about how the magnetic flux was originally computed for the sun and its relation to the change in area as the star shrinks. Some participants suggest using proportional relationships based on surface area to estimate the white dwarf's flux.

Discussion Status

The discussion is ongoing, with participants actively questioning assumptions about magnetic flux and its dependence on physical characteristics of the stars. There is a recognition of the need for further research into the charge distribution and dynamics within the sun and white dwarf, indicating a productive exploration of the topic.

Contextual Notes

Participants note the lack of explicit information on how the magnetic flux was computed for the sun, which is referenced in the exercise. There is also mention of excluding the dynamics of convection within stars, which may influence the magnetic fields.

Aleolomorfo
Messages
70
Reaction score
4

Homework Statement


The sun has a rotational period of 25 days. Finding the rotational period if it can shrink to form a white dwarf (##R_{WD}=10^3Km##). Knowing that the density of magnetic flux of the Sun on the surface is ##1 Gauss##, finding the magnetic flux of the white dwarf.

Homework Equations

The Attempt at a Solution


For the first part I can use the conservation of momentum ##I_{sun}\omega_{sun}=I_{WD}\omega_{WD}## with ##I\propto MR^2## and also with the hypothesis that there is no loss of mass during the shrinking. I have found that the period is 4.4##s##. However, I do not know how to do the second part about the magnetic flux. Should not be the same? But I am not even sure about this conclusion which I see it has not a proof.
 
Physics news on Phys.org
How was flux computed for the sun? Is it related to the change in area from sun to white dwarf?
 
jedishrfu said:
How was flux computed for the sun? Is it related to the change in area from sun to white dwarf?

I do not know how the flux was computed for the sun, it is in the text of the exercise. If it is related to the change of area, I will make a proportion:
$$\frac{Flux_{sun}}{R_{sun}^2}=\frac{Flux_{WD}}{R_{WD}^2}$$
 
Aleolomorfo said:
I do not know how the flux was computed for the sun, it is in the text of the exercise. If it is related to the change of area, I will make a proportion:
$$\frac{Flux_{sun}}{R_{sun}^2}=\frac{Flux_{WD}}{R_{WD}^2}$$
The sun is a rotating ball of plasma. What is the distribution of charge in the sun? How much magnetic flux will be generated as a result of its rotation? Will the distribution of charge in a white dwarf be similar? It's time to do some research and/or make some assumptions.
EDIT: I am leaving out entirely the dynamics of convection within stars, which I think will dominate the magnetic fields of both M-class stars and white dwarves.
 
Last edited:

Similar threads

  • · Replies 7 ·
Replies
7
Views
6K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 5 ·
Replies
5
Views
5K
  • · Replies 1 ·
Replies
1
Views
6K
Replies
22
Views
5K
  • · Replies 3 ·
Replies
3
Views
13K
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
4K
Replies
1
Views
8K
  • · Replies 1 ·
Replies
1
Views
4K