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Staring at a Red Dwarf harmful?

  1. Apr 11, 2013 #1
    If we lived in a solar system with a red dwarf, and it had the same apparent size as the Sun, would it be harmful for our eyes to look at?

    If not, then how much closer would you have to get?

    Just curious, and I might use this info for fiction.
     
  2. jcsd
  3. Apr 11, 2013 #2
    The habitable zone for a planet would have to be much closer.
    The HZ zone for a planet with a Red dwarf sun with a luminosity of 0.02 the HZ would be roughly 0.14 the distance between Earth and our own sun.
    the visual L isn't hazardous to the eyes unless one considers the HZ distance. Although red dwarfs produce high X UV radiation. Much of that can be filtered out by atmosphere.

    However the closeness of the HZ is in high risk of stellar activity such as solar flares etc.
     
    Last edited: Apr 11, 2013
  4. Apr 11, 2013 #3
    I located the article that I recalled that HZ distance from.
    http://arxiv.org/abs/0901.1860
     
  5. Apr 13, 2013 #4

    mfb

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    Stars with 2% the solar luminosity have a surface temperature of ~3400K, or ~1/16 times the brightness of sun. I would expect that this is still dangerous.
     
  6. Apr 13, 2013 #5

    Vanadium 50

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    Looking at the sun during an eclipse is dangerous - I can't imagine looking at a redder star without a moon in front of it could possibly be less dangerous.
     
  7. Apr 13, 2013 #6
    Look at a candle flame long enough can be harmful to the eyes. If I misimplied that in my earlier post that was not my intention.
     
  8. Apr 13, 2013 #7

    Bandersnatch

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    Wait, why is that? Shoudn't they have the radiation spectrum shifted towards infrared, rather than UV?(as compared to the Sun). It is a black body spectrum, after all - or so I thought.
     
  9. Apr 13, 2013 #8
    The high X UV is created during flare ups I was going to post another article that mentions it but I'm having trouble getting the link to work from my phone lol
     
  10. Apr 13, 2013 #9

    Bandersnatch

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    I swear you've had this article linked here just a moment ago, but now you don't:
    http://www.as.utexas.edu/astronomy/education/spring02/scalo/heath.pdf

    Maybe it's my saturday's altered sobriety playing funky games with my brain, but assuming that you had, then it(the paper) seems to say that during the largest flares the UV band irradiation merely reaches the regular, quiescent levels we get from the Sun:

     
  11. Apr 13, 2013 #10
    Yeah that was the article for some reason it was linking wrong when I used my phone.

    Thanks for the clarification on the UV levels I was wondering on that myself hence looking for other references
     
  12. Apr 13, 2013 #11
    If it's a total eclipse, you can stare at it though. Can't you?

    Well of course. I can imagine, any light source can be harmful with the right distance and time.

    But with the Sun, it doesn't take very long at all to be harmful. So I'm wondering how a red dwarf, with the same apparent size, would compare.
     
  13. Apr 13, 2013 #12

    Vanadium 50

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    Well, you can, I suppose. Doesn't mean you should. 1% of the sun is more than enough to cause eye damage.
     
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