Can we see sunspots on other stars?

[Pradeepkumar]

Others stars contain sunspots,don't they??

Edited August 22, 2008 by Pradeepkumar
Wrong question

[insane_alien]

we are pretty sure they have sunspots but we do not have telescopes powerful enough for direct observation yet.

[CaptainPanic]

Not even our nearest neighbors? Alpha Centauri is only about 287,000x as far as the sun... rather disappointing I must say.

 

Sun = 8 light minutes

Alpha Centauri = 4.37 light years = 4.37*365*24*60 / 8 = 287,000x distance earth - sun

 

The sun is big enough to see sunspots with the naked eye (ok, with a filter, but no telescope needed) and we have equipment that can magnify things more than 287,000 times... At least, that's what I thought.

Edited August 22, 2008 by CaptainPanic
adding calculation for factor 287,000

[Klaynos]

It's the resolution which is the issue here not the magnification... We just can't resolve things that are that small with current telescopes.

[CaptainPanic]

In other words, we can make it as big as the sun (on a picture) but it'll be a bit of a blur?

[D H]

A largish cluster of sunspots on the Sun is about 20 Earth diameters across. The angle a similar sized cluser would subtend on Proxima Centauri is

 

[math]20\cdot2\cdot 6378\,\text{km} / 4.2\,\text{light years} = 3.2\cdot10^{-9} = 1.3\,\text{mas}[/math]

 

Seeing such a cluster even on the closest star would require a telescope capable of twice that resolution to avoid aliasing problems, or less than a milliarcsecond. In comparison, the best telescopes do not yet have the resolution to see the objects the Apollo project left on the Moon, and doing that would require a telescope capable of seeing things at the 2.7 milliarcsecond level.

[Arch2008]

Scientists can detect magnetic disturbances on the surfaces of tiny red dwarf stars.

http://www.sciencedaily.com/releases/2007/12/071205095342.htm

 

A red dwarf is only a few percent of the size of our Sun, so it may be possible to detect the magnetic side effect of “solar spots” on larger stars. It’s just never been attempted.

 

http://www.grantchronicles.com/astro25.htm

 

As to the second question, I think that we know enough about stars to say that they have spots too.

[CaptainPanic]

I found this on Slashdot today:

 

http://arxiv.org/abs/0808.2386

 

Seems that somebody did find stellar spots (or at least a dip in the brightness), and mistook them for a giant Jupiter-like planet first.