Colours of stars
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Colours of stars
Emirates airlines has a forward looking camera so that passengers can watch the take-off. Last night, on rotation, the forward camera gave a great scope of the night sky. I was interested to see that the stars were of different colours on the screen. I am wondering if this is due to the different magnitudes of stars.
Anyone of a scientific bent who would try to explain this phenomenon? Thanks for any info.
Anyone of a scientific bent who would try to explain this phenomenon? Thanks for any info.
Refraction is the word here. Stars at different elevations are viewed through more or less atmosphere (Higher elevation = less air between you and star) thus the light from them is "bent" to differing degrees. A good example is actually the planet Venus which can appear red at very low angles but is clearly white when higher in the sky............
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Don't forget that, as well as refraction effects, the stars look different colours because they, in fact, different colours!
Magnitude isn't really a factor - stars are different colours depending on their temperature (itself dependent on size). Cooler stars arr red or orange. Hotter ones are white or blue.
The effect is noticable from here on Earth - Sirius is the brightest star in the northern hemisphere and is a prominent white. Betelgeuse (the left shoulder of Orion) is an unmistakeable red-orange colour as it is a lot cooler (and older) than Sirius.
Like ETOPS said, refraction will pay a part - have a look at the colour of the Moon when it's very close to the horizon - it's definately more orangey.
Our eyes can pick this up...whether the fidelity of the these cameras is good enough to I wouldn't know...
Regards,
V1R
Magnitude isn't really a factor - stars are different colours depending on their temperature (itself dependent on size). Cooler stars arr red or orange. Hotter ones are white or blue.
The effect is noticable from here on Earth - Sirius is the brightest star in the northern hemisphere and is a prominent white. Betelgeuse (the left shoulder of Orion) is an unmistakeable red-orange colour as it is a lot cooler (and older) than Sirius.
Like ETOPS said, refraction will pay a part - have a look at the colour of the Moon when it's very close to the horizon - it's definately more orangey.
Our eyes can pick this up...whether the fidelity of the these cameras is good enough to I wouldn't know...
Regards,
V1R
Está servira para distraerle.
There is an arguement in this part of the world, that the colour of the stars varies in inverse proportion to the amount of local rum imbibed. But then, from the Equator; I suppose refraction is of equal effect all around the observer.The same potential for discrepancy is also rumoured to be true as to the varied prismatic phenomenon of the rainbow. It weaves its glorious incandescent pathway through the heavens, starting nowhere and ending, equally, nowhere; but leaving a glorious memory of its passing for all to observe as it wends its passage through the superhighway of the sky.
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Star tempratures
To add to V1 R comments
please take a look at
http://curious.astro.cornell.edu/stars.php
Stars and colours vary in temp from
80.000deg k over 8 main bands down to 2000-3000 deg k
our sun is 5800deg k and is yellow.
The web site give other main details. One point that is hard to accept is that some stars are massive and can be as big as our solar system!!!!!!!
Cheers Orion
please take a look at
http://curious.astro.cornell.edu/stars.php
Stars and colours vary in temp from
80.000deg k over 8 main bands down to 2000-3000 deg k
our sun is 5800deg k and is yellow.
The web site give other main details. One point that is hard to accept is that some stars are massive and can be as big as our solar system!!!!!!!
Cheers Orion
What a brilliant website. Thank you for the pointer.Rotate on this!
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Don't forget that, as well as refraction effects, the stars look different colours because they, in fact, different colours!
er...is that correct?
Not arguin - just intrigued as to how that may be...I thought the 'brightness' was relative to the energy released and any perception of colour was particle interferance related.
Is energy coloured?
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Brightness IS related to energy released, but the brightness of an object is a separate property to it's colour (although they are interrelated - see the Planck radiation law if you're interested).
http://csep10.phys.utk.edu/astr162/l...radiation.html
In summary, as it has been said previously the hotter an object the more of it's radiation is emitted towards the blue end of the visible spectrum and vice versa. Imagine what a metal rod looks like as you heat it and it first turns red and then more yellow before it becomes white-hot.
In terms of stars:
The Sun: ~6000 degrees -> yellow
Sirius: ~32000 degrees -> blueish
Betelgeuse: ~3000 degrees -> red
http://csep10.phys.utk.edu/astr162/l...radiation.html
In summary, as it has been said previously the hotter an object the more of it's radiation is emitted towards the blue end of the visible spectrum and vice versa. Imagine what a metal rod looks like as you heat it and it first turns red and then more yellow before it becomes white-hot.
In terms of stars:
The Sun: ~6000 degrees -> yellow
Sirius: ~32000 degrees -> blueish
Betelgeuse: ~3000 degrees -> red
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SLFguy,
Yep, the stars are indeed different colours! mbcxharm explains it well.
Not sure what you mean by particle interference related but in answer to your question:
Is energy coloured?
The light we see is just one type of electromagnetic (EM) radiation characterised by a certain range of frequencies/wavelengths. X-rays, microswaves, gamma-rays, etc. are all other types of EM radiation, again, with different frequencies/wavelengths to visible light.
Our eyes are sensitive to visible light and our brains interpret different frequencies of visible light as different colours. So, in essence, different energies (read "frequencies") of light are detected by our eyes as different colours. In answer to the question: light of different energies appears, to humans, as different colours.
Cheers,
V1R
Yep, the stars are indeed different colours! mbcxharm explains it well.
Not sure what you mean by particle interference related but in answer to your question:
Is energy coloured?
The light we see is just one type of electromagnetic (EM) radiation characterised by a certain range of frequencies/wavelengths. X-rays, microswaves, gamma-rays, etc. are all other types of EM radiation, again, with different frequencies/wavelengths to visible light.
Our eyes are sensitive to visible light and our brains interpret different frequencies of visible light as different colours. So, in essence, different energies (read "frequencies") of light are detected by our eyes as different colours. In answer to the question: light of different energies appears, to humans, as different colours.
Cheers,
V1R
