# Variations in the speed of sound in a star

• I
• fab13
In summary, the speaker is seeking clarification on the graph shown with the x-axis representing the radius of a typical star and the y-axis representing the relative error or fluctuations in speed of sound. They are unsure of the exact meaning of the y-axis and are requesting help and clarification from others with knowledge in stellar physics. They also ask for the source link of the lecture and inquire about the origin of a discrepancy in the graph.

#### fab13

I try to understand the following graphics with x-axis being the radius of a typical star :

I would like to knwo if ##\delta c/c## (y-axis) represents the relative error between theoretical and experimental values or if it represents the fluctuations of speed of sound inside. If these are fluctuations, one could get the mean speed all over radii or standard deviation.

I am not sure what it is exactly.

Any help is welcome

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Can you give the source link? Even when using the Upload feature to attach a figure to your post, it is a good practice to post the source link. It also helps to avoid copyright issues. Thanks.

lecture is available on this link

fab13 said:
I would like to knwo if δc/c\delta c/c (y-axis) represents the relative error between theoretical and experimental values...
That's it. As explained in the graph on the previous page of the presentation you linked.

So the main discrepancy in current models is in the zone 0.4 - 0.65 R/R0 : can anyone could explain what's the origin of this issue ?

at R = 0.4 - 0.65 R0, are we in radiative or convective zone ?

Regards

Could anyone help me on this current discrepancy ? or if someone had stellar physics knowledge ... thanks

## 1. What causes variations in the speed of sound in a star?

Variations in the speed of sound in a star can be caused by changes in the temperature, density, and composition of the star's interior. These factors affect the way sound waves travel through the star's medium.

## 2. How do scientists measure variations in the speed of sound in a star?

Scientists use a technique called asteroseismology to measure variations in the speed of sound in a star. This involves studying the oscillations of the star's surface, which can provide information about the internal structure and sound speed of the star.

## 3. Why is it important to study variations in the speed of sound in a star?

Studying variations in the speed of sound in a star can provide valuable insights into the star's internal structure and composition. This can help us better understand the processes that drive stellar evolution and the formation of elements in the universe.

## 4. Do all stars have the same variation in the speed of sound?

No, not all stars have the same variation in the speed of sound. The speed of sound is affected by factors such as the star's mass, temperature, and age. Therefore, different types of stars may have different variations in their sound speeds.

## 5. Can variations in the speed of sound in a star affect its lifespan?

Yes, variations in the speed of sound in a star can affect its lifespan. Changes in the sound speed can impact the way energy is transported within the star, which can affect its overall stability and longevity. This is why studying variations in the speed of sound is important in understanding the life cycle of stars.