# Stars Rotation | What is Angular Momentum?

• shounakbhatta
In summary, stars do rotate due to angular momentum acquired during their protostar phase. This rotation continues even after the star is fully formed, with the sun's equator completing one rotation in about 24 and a half days.
shounakbhatta
Hello,

Do stars rotate? I mean to say that do they rotate in angular momentum? Or there is any other rotation?

Yes, stars rotate due to angular momentum acquired from gravitational collapse during their protostar phase.

Hello,

Thanks. I believe pro star is the earlier stage of star formation. What happens when the star if finally formed? Does it have a angular momentum then also?

The star we know best, our sun, is "finally formed" and it rotates. According to wikipedia, http://en.wikipedia.org/wiki/Solar_rotation
its equator makes one rotation in about 24 and a half days. Of course, because it is gaseous, different parts, at different latitudes, can rotate at different rates.

## 1. What is the definition of angular momentum?

Angular momentum is a measure of the rotational motion of an object. It is the product of an object's moment of inertia and its angular velocity.

## 2. How does the rotation of stars affect their angular momentum?

The rotation of a star directly affects its angular momentum. As a star rotates, its angular velocity increases, resulting in an increase in its angular momentum.

## 3. How is angular momentum conserved in stars?

Angular momentum is conserved in stars through the conservation of angular velocity. As a star contracts, its moment of inertia decreases, causing its angular velocity to increase and maintain the same angular momentum.

## 4. How does the distribution of mass in a star affect its angular momentum?

The distribution of mass in a star can greatly affect its angular momentum. A star with most of its mass concentrated towards the center will have a smaller moment of inertia and a higher angular velocity, resulting in a larger angular momentum.

## 5. Can the angular momentum of a star change over time?

Yes, the angular momentum of a star can change over time. Processes such as mass loss, collisions with other objects, and changes in the distribution of mass within the star can all alter its angular momentum.

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