Understanding the Rotation of Stars: Origins and Processes

[shirin]

Does sun rotate around itself?
Do all of stars rotate around themsilves? If so, what is the origion of this rotation?

 

[Phrak]

angular momentum?

 

[HallsofIvy]

Yes, the sun rotates. It is easy to see that by keeping track of sunspots.

As to whether all other stars rotate or not, we cannot see them clearly enough to determine by observation but it would be very surprising if it were not so. In order that a start NOT rotate, its angular momentum, as Phrak suggests, would have to be exactly 0. It would very odd for a quantity like that to have a value of exactly 0.

 

[jtbell]

As to whether all other stars rotate or not, we cannot see them clearly enough to determine by observation

There are apparently at least two ways to observe the effects of stellar rotation: broadening of spectral lines via the Doppler effect, and variations in brightness caused e.g. by sunspots moving in and out of view.

http://www.mtwilson.edu/hk/History/

 

[shirin]

Thanks for your answers and interesting page!
Is it clear what the origion of stars' rotation is?

 

[Alex1995]

magic?

 

[Alex1995]

ok scratch my last answer. i am new and only 16 but i think its like this:

I have seen many posts saying that the stars spin, the spin is provoked by the conservation of angular momentum.
This is a theory though, since we cannot tell for sure if other stars rotate like our sun.

Though Pulsars rotate, the theory on this is: you take a large object with a slight rotation and compress it down, the rotation speed will increase.

We know pulsars rotate and can check their rotational speed by calculating by how rapidly they pulse.

The problem is.. We do not know if Pulsars rotate due to the SuperNova explosion or due to the previous star spinning and then being compressed and its rotational speed increasing... A computer simulation was made, and they sadly... found out that the spin was caused by the Super Nova explosion itself. {Meaning that the previous theory is now canceled out}

so... we still don't really know...

(Sorry for my spelling, language) I am not sure my answer is right but i tried.

 

[Vagn]

ok scratch my last answer. i am new and only 16 but i think its like this:

I have seen many posts saying that the stars spin, the spin is provoked by the conservation of angular momentum.
This is a theory though, since we cannot tell for sure if other stars rotate like our sun.

Though Pulsars rotate, the theory on this is: you take a large object with a slight rotation and compress it down, the rotation speed will increase.

We know pulsars rotate and can check their rotational speed by calculating by how rapidly they pulse.

The problem is.. We do not know if Pulsars rotate due to the SuperNova explosion or due to the previous star spinning and then being compressed and its rotational speed increasing... A computer simulation was made, and they sadly... found out that the spin was caused by the Super Nova explosion itself. {Meaning that the previous theory is now canceled out}

so... we still don't really know...

(Sorry for my spelling, language) I am not sure my answer is right but i tried.

Of course we can't know exactly for sure, but any star that has planets must be rotating as well, otherwise the planets wouldn't rotate as there would be know angular momentum in the initial cloud, which would completely condense into a star. Binary systems must similarly be rotating initially, and hence any stars would also rotate, it would require an initial momentum of exactly zero in the dust cloud for a star not to spin, which is highly unlikely, hence we can conclude that most if not all stars rotate.

 

[Chronos]

Stars are formed by gravitational collapse of primordial gas clouds. Rotation is imparted as a consequence of molecular collisions during collapse.

 

[Ken G]

What's more, it might be noted that star's don't rotate like solid bodies, because they are gaseous, not solid. They exhibit "differential rotation", which means the rotational period (the "day") varies with latitude on the surface. It also varies in the interior, so the angular momentum history is very complex.