[NA] Astronomy math help

[Let'sgoflying!]

This article talks about a star that is spinning fast. Really fast.
I want to calculate the star's speed at its equator in mph.
ie: if the speed of a 'star particle' on the surface, at the fastest point (the equator if that is the right term for stars) could be measured with a celestial speed trap, what would it be?
(I think its saying 716rps and a dia of 12mi)
Do your calculation and then compare to my rough math below, let me know if I was off.

I get roughly 97million mph. (btw, what is the correct answer compared to the speed of light?)

 

[Matthew]

Circumference = 2pi x r (I get 2pi x 6 = 38 miles)

That gives you miles traveled of a particle on the surface in 1 revolution.

So miles/rev * rev/sec gets you miles/second.

I get 38 * 716 = 27,208 miles/sec.

27208 mi/sec * 60 sec/min = 1,632,480 mi/min

1,632,480 mi/min * 60 min/hr = 98,000,000 mph


Edit: D’oh! I read diameter and thought radius! I edited to clean up that mess.

What’s the gravity to keep it from spinning itself apart?

 

[Bob Noel]

(btw, what is the correct answer compared to the speed of light?)

at the risk of spoiling the spoiler, and assuming my public math is ok, about .15c

Which starts getting into relativistic speeds. and funny things start happening...