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Planetary habitability in proximity to nebulae

  1. Sep 17, 2013 #1
    Hi everyone.

    I would like to apologise in advance for my inherent lack of information in regards to what I am about to ask. I do not have a great understanding of the physics of the universe and such, but I suppose that is partially the reason for forums - to expand knowledge!

    Anyway, I would like to pose a question that I hope someone could answer for me. I am planning to write a science fiction novel soon, but one thing I am attempting to do (that I think many others fail to do, be it novelists or screenwriters) is use as much real science as possible. While there are leaps and bounds such as faster-than-light travel, I want the science of the story to be as plausible and believable as possible.

    The story involves a journey to a habitable planet near the Rosette Nebula. Now, the question I would like to pose is this. Young stars within nebulae obviously emit radiation while forming (and throughout their lifetime). An entire nebula of young stars would no doubt be rather dangerous in this regard. How far away would a planet need to be from such a nebula in order to have Earth-like conditions for life to evolve? Obviously if it were too close to the nebula (and in this case, the Rosette has a radius of 65 light years), I'm speculating the planet's magnetic field and ozone layer would be insufficient to protect the planet from so much radiation, if it were too close?

    On a personal note, it does make one wonder what a nebula like the Rosette would look like from the surface of a planet, especially at night. I imagine it would be quite a beautiful sight!

    Any help will be appreciated!
  2. jcsd
  3. Sep 18, 2013 #2
    Honestly I think it's quite a difficult question you're asking. When you mean habitable, you're certainly talking about human-wise conditions, and we require a lot and i do mean a lot in order to make a planet habitable: a decent atmosphere, acceptable day/night temperature, water, oxygen, etc...
    Which all relates essentially to the surrounding of your planet, much like the nature of this planet itself.
    The real issue here, is that the location for your fictional planet is near a nebula; obviously it's almost impossible to find a suitable planet inside of a nebula because it is known that the latter is region where stars are born, and born in large numbers so the heat will make the place unhospitable.
    In any case for your novel, even staying near a nebula is dangerous, so in my opinion bend the rules, take a gamble and make it about 1 light year away from the edge of the nebula so that the scene will be beautiful (hospitable? not sure).
  4. Sep 18, 2013 #3
    Thanks for your reply, Magna.

    Yeah I realise now it is quite a difficult question I am asking! As the Rosette has a 65 light year radius, I was initially thinking of placing the planet around 2-4 light years from the nebula. I'm speculating that even at such a distance, a nebula that is 65 light years across would still look pretty large in the night sky of the planet?
  5. Sep 19, 2013 #4
    Here's a link that shows some observable stars and how distant they are just for reference http://en.m.wikipedia.org/wiki/List_of_brightest_stars.
    You can see that some observable stars (not necessarily by the naked eye but still) are located from 4 to 400+ light years away. Obviously a 400 light year star would be almost impossible to observe by the naked eye, but a 4 light year cluster of large stars would be still visible.
    Keep in mid the following: if you can see a lot of large stars => you are recieving the heat and energy of these stars which can make the planet unhospitable.
    Anyhow 2-4 light years seems pretty okay for a good view.
  6. Sep 21, 2013 #5
    Why not work out the numbers?

    I once did for how close one can safely get to a very bright star.

    Main sequence - Wikipedia Theta1 Orionis C (O6pe V) is one of the brightest known stars at 500,000 solar luminosities. 'll use that as a reference case. So to get the Sun's luminosity from it would require being at 710 AU or 0.0034 pc. That's still much smaller than typical interstellar distances.

    The Rosette Nebula's size is about 40 parsecs / 130 light-years. So if one was inside it, one would still be a safe distance away from its OB stars. Even if one was among them, one would likely be a safe distance away from them.

    Rosette Nebula - Wikipedia
    Rosette Nebula
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