Arter21 Posted January 11, 2005 Report Share Posted January 11, 2005 Greetings everyone... I'm new here and was wondering if any of you chaps/ladies had any idea of the following? For a species similar to ourselves to exist on a planet, at what approximate distance would a planet need to be from the various types of star? I appreciate that there are lots of variables both with regards the star and the planet that will make this question difficult to answer accurately, so really you could say I'm interested in the approximate upper and lower limits. Primarily I'm interested in redwhiteblue supergiants, whiteblue main sequence stars and white dwarves. Many thanks :Alien: Link to comment Share on other sites More sharing options...
maddog Posted January 12, 2005 Report Share Posted January 12, 2005 For a species similar to ourselves to exist on a planet, at what approximate distance would a planet need to be from the various types of star? I appreciate that there are lots of variables both with regards the star and the planet that will make this question difficult to answer accurately, so really you could say I'm interested in the approximate upper and lower limits. Primarily I'm interested in redwhiteblue supergiants, whiteblue main sequence stars and white dwarves. Many thanks :) Given these parameters, I'd suppose the following. Suppose that our star went nova (G2 main sequence star). Once done its size would extend out to just past mars. So any planetfrom Mercury to Mars wouldn't exist. It is thought that a moon of Jupiter or better Saturnwould then be in a "habitable life zone". Thus Titan 4 or 5 billion years hence will becomea habitable planet (maybe). As you go up the main sequence of stars (hotter) towards F or A type stars. The distancewould have to be further out. For O and B stars the end is more likely a black hole at thecenter (most of these stars exceed 10 solar masses), and so would not likely be habitableat all. Hope this helps. :) Maddog Link to comment Share on other sites More sharing options...
Arter21 Posted January 12, 2005 Author Report Share Posted January 12, 2005 That does help a bit, cheers maddog, but it's not really exactly what I was after... Basically I'm writing a short story and I want the information in it to be based in reality. As it'll be set on several different planets in different star systems, I don't really need to know about the habitable distance over a period of time, rather just at the specific stage of the stars life. Waht I don't want is to have a planet goign round a blue giant at say, 45 AU's and then later find out that at that distance the radiation/heat/electromagnetic field of the star would rip the planet to shreds and any life thereon. Thanks for the reply though, I can at least get an agreeable distance for a red giant, thanks to you... :) Link to comment Share on other sites More sharing options...
maddog Posted January 12, 2005 Report Share Posted January 12, 2005 Basically I'm writing a short story and I want the information in it to be based in reality. As it'll be set on several different planets in different star systems, I don't really need to know about the habitable distance over a period of time, rather just at the specific stage of the stars life. Waht I don't want is to have a planet goign round a blue giant at say, 45 AU's and then later find out that at that distance the radiation/heat/electromagnetic field of the star would rip the planet to shreds and any life thereon. Thanks for the reply though, I can at least get an agreeable distance for a red giant, thanks to you... :) You're welcome. I would caution against using much bluer beyond about B8 or so. They tendto be bigger as they get hotter and have less of lifetime. I would think towards the end lifeof any main sequence star A-K would generate a nice system nicely. I would like to read it when the story is done. Let me know where you plan to publish, so Ican find it. Later. Maddog Link to comment Share on other sites More sharing options...
pgrmdave Posted January 12, 2005 Report Share Posted January 12, 2005 Wouldn't a larger star also produce more harmful radiation than a smaller star, meaning that any life around it would either need to have developed ways to counter it, or the planet would need to have an atmosphere that could deflect it, like our ozone layer, but thicker? Link to comment Share on other sites More sharing options...
maddog Posted January 13, 2005 Report Share Posted January 13, 2005 Wouldn't a larger star also produce more harmful radiation than a smaller star, meaning that any life around it would either need to have developed ways to counter it, or the planet would need to have an atmosphere that could deflect it, like our ozone layer, but thicker? Actually, I don't know exactly what would be best for his story as I only answere from whatwas given. The rule of thumb is going up the main sequence towards O type star the surface temperaturegoes up. Mass of the star goes up as well (O type stars are more likely larger than A's). Theharmful radiation is indicitive of the temperature (being O or :). The bulk of radiation is inthe band where the center would nearly be UV. Yes, this would much more harmfull. Soeither a thicker atmosphere, with more other things in it, a thicker Ozone layer, etc. Thisstill would all be temporary independant of type of star. Once all the fuel ran out and thestar goes nova (or supernova), even for a star of our size not much would habitable insideof pluto or so. Not enough current data, it is speculative that a supernova would make allobject inside the equivalent of an Oort's cloud melt or molten (nothing left). It all depends. :) Maddog Link to comment Share on other sites More sharing options...
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