Does The Sun Spin ?

[atalanta]

I assume the sun spins, but how fast, and at what angle - if any ?
I have been reading about our sun and other stars , and I see that scientists claim to be able to state how much they weigh. How do scientists/astronomers work out how much a star weighs ?

[jeffa]

https://www.google.co.uk/search?q=sun+spin&oq=sun+spin&aqs=chrome..69i57j0l5.5865j0j7&sourceid=chrome&espv=210&es_sm=93&ie=UTF-8

[atalanta]

What about the angle of spin, if any, and how you weigh a star ?

[Zacs-Master]

Since the Sun consists of a plasma and is not solid, it rotates faster at its equator than at its poles. This behavior is known as differential rotation and is caused by convection in the Sun and the movement of mass, due to steep temperature gradients from the core outwards. This mass carries a portion of the Sun’s counter-clockwise angular momentum (as viewed from the ecliptic north pole), thus redistributing the angular velocity. The period of this actual rotation is approximately 25.6 days at the equator and 33.5 days at the poles. However, due to our constantly changing vantage point from the Earth as it orbits the Sun, the apparent rotation of the star at its equator is about 28 days.

the most accurate method of "weighing" a star is by use of the Doppler shift.
To find the mass of the Sun we take advantage of the planets orbiting it. Each planet requires a centripetal force to keep it from flying away; this force is supplied by the Sun's gravity. Setting these two forces equal to each other we can write an equation (also in introductory physics books):

Force of Gravity = Centripetal Force

(G x MSun x Mplanet) / (r x r) = (Mplanet x V x V) / r

simplifying the equation we see the the mass of the planet cancels out (using algebra) so:

MSun = (V x V x r) / G

Binary stars are used to calculate the weight of other stars.

We measure the velocity of each star (V) using the Doppler shift and the distance between each star the their common center of mass (r) (which is found by taking pictures of the stars through a telescope). So we can find the total mass of the stars using the same equation as above.

[jomifl]

Since we have a pretty good idea of the Earths mass and we know how long it takes to orbit the Sun once and how far the Earth is from the Sun, we can calculate the mass of the sun.

[Old_Geezer]

At what angle.
Relative to what axis ?

[jomifl]

You can see that the sun spins when there are sunspots visible from the Earth. If you make an allowance for the orbital movement of the Earth it is quite easy to calculate the rate of spin of the sun at various solar latitudes.

[vascop]

Yes I'm with OG. The earth's tilt is measured as the angle between its axis of rotation and the perpendicular to the plane of its orbit.
We don't normally think of the Sun as orbiting, so not sure how you would define the tilt of the Sun.

[vascop]

Found this:
http://cosmoquest.org/forum/showthread.php?120734-Sun-axial-tilt-relative-to-Earth-season
which defines the Sun's tilt relative to the orbital plane of the earth - 7 degrees.

[Teddio]

The Sun spins on its axis as do the vast majority of stars. It is likely that the clouds of dust and gas from which the stars and planets form initially had angular momentum.
Have any stars been observed which have zero angular momentum ?

[jomifl]

Vascop, the sun must orbit the common centre of gravity of the solar system, which is presumably somewhere inside the sun at least most of the time.

[atalanta]

I've read all these answers.
So what does our Sun weigh ?
Is there a list of the weights of other stars ?