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The Sun's position relative to the Nearest stars?


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Having in mind that our sun has a yellow colour with a temperature nearly to the 6,000 K - and taking into an account it is located in the middle of the 'Main Sequence' of the HR Diagram - what would be a definition of the sun being relative to the surrounding (nearest) stars?

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I would like to help but I don't understand the question. It's postion in the main sequence is a consequence of it's mass and age and is a typical G2V star being too young to have evolved off the main sequence. If you are asking about our nearest neighbour star what about them do you wish to compare with the Sun.

Regards Andrew

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You should bear in mind that the yellow colour we see is also a function of us mortals looking at it through our atmosphere and the resultant light scattering so induced. Our Sun's surface temperature of close to 5700K actually means that peak wavelength is roughly in the green part of the spectrum!

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Kellytabares can you reword/ try and explain the question?  You sound as if you have a good idea of what you mean but I am finding it difficult to interpret exactly what you are asking.  

We should be weary of putting words into peoples mouths too as this can lead to a different question being answered.  

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Hi,

Sorry I didn't explain the question as I intended to. Basically, we have our sun positioned in the very middle of the sequence due to many factors as Andrew mentions on the above post. So, what can we say about the sun relative to its nearby stars? (in general and not as a objective point of view).

For example, relative to the group of stars in the sun's neighbourhood, what could it be say - or inferred - about its luminosity, mass and/or age. Or, why is it believed that the sun is a "normal" kind of star? Or, what would be the future of the sun relative to the nearby stars, would it grow huge as a giant and then blow itself to pieces OR will it just shrink and compress itself with enough gravity to stop the nuclear fusion and start cooling off for eternity?

Hope I made my question somewhat clear.

Thank

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I think the thing is that the sun is 'unremarkable' rather than 'normal'. I suspect that as we better know the conditions needed for life many other star types will turn out to be unsuitable - variables and binaries, for example, might not provide the consistent long-term conditions needed for life. Dwarf stars may be too small and big bright stars may not last long enough, first generation stars may not exist in areas with enough heavy elements, and stars near galactic centres may be too vulnerable to 'wipeouts' caused by novas, supernovas etc.

As for the future, I understand the sun will become cooler but expand out to the orbit of Mars, then gradually cool and shrink to become a brown dwarf.

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I think the thing is that the sun is 'unremarkable' rather than 'normal'. I suspect that as we better know the conditions needed for life many other star types will turn out to be unsuitable - variables and binaries, for example, might not provide the consistent long-term conditions needed for life. Dwarf stars may be too small and big bright stars may not last long enough, first generation stars may not exist in areas with enough heavy elements, and stars near galactic centres may be too vulnerable to 'wipeouts' caused by novas, supernovas etc.

As for the future, I understand the sun will become cooler but expand out to the orbit of Mars, then gradually cool and shrink to become a brown dwarf.

...white dwarf is most likely and a resulting planetary nebula.

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The Sun is considered "normal" simply because the class it belongs to (Yellow Dwarfs) is extremely common when we look into the Universe in fact the second most common type of star, Red Dwarfs being the most numerous.  Our Sun was born from the debris of older generation stars that went supernova. It is generally regarded that there have been 3 generations of stars the oldest being 3rd generation and the most recent (including our Sun) are 1st generation. A little confusing but its because the when we look out into space 1st generation stars are the first we come across. As mentioned our Sun and all the main sequence stars we see today are formed from older generation stars and therefore have all formed within a given time frame. Hence the reason that most stars we see today sit in the prime sequence i.e are in the prime of their lives, mid life. Being formed of older stars that went supernova also means that their chemical makeup limits the forming process to Yellow and more commonly Red dwarf stars. Stars that dont sit on the main sequence fall into the following.There are some stars that are formed of more pure material which results in large bright blue or white stars. Also newly formed stars burn very bright for a while and are therefore blue or white. Stars that are reaching their end of life expand massively which results in surface cooling and these become red giants or supergiants. There are also stars that are the core relics of once massive stars that have went supernova, these are Pulsars, Neutron Stars and Magnetars. The life period of stars is governed by it size and luminosity, bright large stars have short life spans. Smaller dimmer stars have long life spans. Our Sun being small and dimmer has a long life span of around 11 billion years, Red dwarfs (its thought) may live as long as a Trillion. When our Sun reaches end of life it will expand to an area that may engulf Mars due to internal chemical processes. However it will not explode (supernova) it will simply puff off its outter shell resulting it what is know as a planetary nebula, Cats Eye and Helix nebula's being examples. The left over core will be a white Dwarf which all internal fusion will of ceased. This core will slowly cool and it will become a black dwarf although the likely time period for this is well....not worth thinking about.

In relation to the Suns neighbours first off you need to decide what counts as a neighbour? Same galaxy? within a few thousand light years etc?

If you say within a thousand light years then most of the neighbours are indeed Yeloow and Red dwarf stars in the main sequence. However there are some notable exceptions,  Betelgeuse a red supergiant, Rigel a massive hot blue star, Deneb another massive blue star etc.

Hope thats helps

Oh and anybody feel free to correct any mistakes.

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