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Earl

What Colour is our Sun?

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If we were a light year away from it what colour would it be, what star would it look like by comparison?

Now this also get me wondering, do we have a tint in the light we see with out eyes do to our sun in daylight? (Tint is very obvious to see in man made lighting)

How would our world look under the light of different stars?

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Find a main sequence star with G2 spectral class, that's our Sun to a "T".

The light from M class stars would be similar to tungsten lighting (actually more like a photoflood lamp, i.e. 3400K rather than 3200K). Light from O class stars similar to light from a carbon arc lamp. Other stars somewhere between these extremes.

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it depends, lol

the sunlight, to us, appears as pure white - this makes sense, as our eyes evolved under it, so their response curves are optimized to work under its light, hence it appears to have no tint.

however, looking directly at the sun, you will see it as yellow, or red, as it sets, this is because as the light passes through the atmosphere, the blue light is scattered - giving the sky its blue colour - leaving behind yellow / orange / red when viewed directly

the sun is classified as G2V, the scale goes like this for historical reasons: OBAFGKM (Oh Be A Fine Girl Kiss Me) with O being the hottest, and hence bluest, and M being the coolest, and hence reddest.

Alpha centauri a is also a G2V, and alpha cen b is a K1V, so not far off, so that's how we look from 4 light years :rolleyes:

now, your last question, if our star were a different spectral type, our eyes would presumably have evolved to see that colour as white.

but imagine we went to another world, or we're around when the sun turns to red giant stage, we would see the light as tinted blue or red. a red star would look a little like our sun during sunrise/set, and you'll find sunrise light is tinted yellow/red, that's what it would be like.

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also, the sun is actually brightest in green light, so one could also conceivably classify it as a green star...

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brianbs lighting analogies are much better, i didnt think of terrestrial sources, won't look at a tungsten light the same way again, ha ha

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Have you seen the link below about Alpha Centauri below, its 4 light years and very similar to Sol.

I cant understand why in the search for other planets so much attention is paid to giant planets around distant stars when Alpha Centauri almost certainly has planets which could harbour life.

I realise we dont have instruments capable of detecting Earth size planets around stars as they are to bright but it seems to me Alpha Centauri is the best candidate.

Space.com : A Quick Trip to Alpha Centauri

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It would be very hard to detect Jupiter from Alpha Centauri ... much easier from a much greater distance if the orbits were such that Jupiter were to pass in front of the Sun (giving a 0.01 mag drop during the eclipse) but given that the event would occur only once every 12 years and last ~30 minutes you'd need to be exceptionally persistent to catch it. All the other planets are much more difficult, except Earth which has artificial radio broadcasts streaming from it.

The "attention paid to giant planets around distant stars" is because they've been detected - mostly because they're relatively easy to detect by either radial velocity periodicity or eclipses.

Edited by brianb

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Yellow seems to the popular colour, although I've heard it is a Girly Star, and is a pinkish shade.

I guess that will excite our Lulu.:rolleyes:

Ron.

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This focus on giant, hot planets may soon be about to change: the Kepler mission has discovered 706 candidate exoplanets in its first 43 days of operation, and theres a fairly good chance of there being at least a couple of 'Earth-like' worlds in there.

Of course, it will take several years to confirm these readings. but this is only the beginning...

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the sun is classified as G2V, the scale goes like this for historical reasons: OBAFGKM (Oh Be A Fine Girl Kiss Me) with O being the hottest, and hence bluest, and M being the coolest, and hence reddest.

Don't forget L and T dwarfs (which are Mauve by the way!) :rolleyes:

Oh Be A Fine Girl Kiss My Lips Tenderly

Re: planets. People have looked for planets around alpha-cen (and most other bright/nearby stars), and haven't found them. This could be because they are below our current detection limits of course. In terms of direct detection (imaging), we're currently limited to things a few times the size of Jupiter. The next generation of instruments should be able to detect (image) young Jupiter-like planets (<100Myr old), and the next generation of telescopes should be able to image true Jupiter analogues (5Gyr old around solar type stars).

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Don't forget L and T dwarfs (which are Mauve by the way!) :rolleyes:

Oh Be A Fine Girl Kiss My Lips Tenderly

Re: planets. People have looked for planets around alpha-cen (and most other bright/nearby stars), and haven't found them. This could be because they are below our current detection limits of course. In terms of direct detection (imaging), we're currently limited to things a few times the size of Jupiter. The next generation of instruments should be able to detect (image) young Jupiter-like planets (<100Myr old), and the next generation of telescopes should be able to image true Jupiter analogues (5Gyr old around solar type stars).

oh yeah, i always forget about those little fellas, lol. I read a fascinating paper recently about the possibility of brown dwarfs having planets and a habitable zone stable enough for the evolution of life, and since they are potentially far more common than all other stellar types put together, and there might even be a couple of the little blighters closer than Proxima Centauri that we havent spotted yet... food for thought, huh?

Brown Dwarf Planets and Habitability

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