Star Colors

[hazelm]

A question for someone who has been fortunate enough to get to look through one of our huge, modern telescopes and viewed stars thousands or millions of light years away.  When you see stars this way, do they reveal any colors?  Or perhaps someone has read such a description?

[exchemist]

A question for someone who has been fortunate enough to get to look through one of our huge, modern telescopes and viewed stars thousands or millions of light years away.  When you see stars this way, do they reveal any colors?  Or perhaps someone has read such a description?

I once looked through an optical telescope at an observatory and saw a dim little thing that was a sort of grey colour. But I imagine colours can be seen if the star is bright enough. Certainly, whether the human eye can see the colours or not, it is usual practice to attach a spectrometer to the telescope and split the light into its spectrum. That allows different elements present to be detected by their spectral lines, and so forth.

[hazelm]

I once looked through an optical telescope at an observatory and saw a dim little thing that was a sort of grey colour. But I imagine colours can be seen if the star is bright enough. Certainly, whether the human eye can see the colours or not, it is usual practice to attach a spectrometer to the telescope and split the light into its spectrum. That allows different elements present to be detected by their spectral lines, and so forth.

Thanks.  That tells me what I can do with my picture.  I do remember an astronaut saying Earth really does look blue from the moon.  And we know Mars is red from its high iron content.  But, I didn't know about stars (burning suns).

[exchemist]

Thanks.  That tells me what I can do with my picture.  I do remember an astronaut saying Earth really does look blue from the moon.  And we know Mars is red from its high iron content.  But, I didn't know about stars (burning suns).

The colour of incandescent objects depends on their temperature. So stars with a cooler surface will radiate more at the red end of the spectrum and very hot ones more at the blue end. The elements I was talking about are often detected by their absorption spectrum, as dark lines on the bright continuous background due to the incandescent emission. This is because there will be cooler regions in the atmosphere of the star where these elements intercept some of the light and absorb it at their own special frequencies, leaving dark lines where some of the light has been absorbed in this way. 

[hazelm]

The colour of incandescent objects depends on their temperature. So stars with a cooler surface will radiate more at the red end of the spectrum and very hot ones more at the blue end. The elements I was talking about are often detected by their absorption spectrum, as dark lines on the bright continuous background due to the incandescent emission. This is because there will be cooler regions in the atmosphere of the star where these elements intercept some of the light and absorb it at their own special frequencies, leaving dark lines where some of the light has been absorbed in this way. 

I'll tend to both ends.  Thank you.

[Deepwater6]

PBS Just put out an episode, ep(45) if you want to find it online. It had a lot of information about this and other things. The episode is called "Black Hole Apocalypse" despite the title they spend quite a bit of time explaining what star spectrums have taught them. They delved into the Doppler Effect, redshift, and the ways astronomers mark the distance of stars with parallax method.  

 

It was nice to get actual information instead of the usual bubble gum tag-line info you hear on Sci. Channels "How the universe works" over and over again.

 

They also touched on the LIGO discoveries which was very interesting. The ability of LIGO to detect gravitational waves didn't get the headlines it deserved in my opinion, but the detection of these waves will help us learn a lot more about what's happening in space and when it happened. 

[DaveC426913]

For one with good eyes, tt is quite possible to see the red tint of Arcturus and the blue tint of Sirius unaided.