The Milky Way Project Talk

How common are planetary nebula?

  • chelseanr by chelseanr

    Hey Guys,

    I was just wondering how common these should be? I find something that LOOKS like one ever 4-5 classifications, and in others it looks like there are tonnes. Here are a few examples of the better ones that I think I've found : http://talk.milkywayproject.org/collections/CMWS000065

    Thanks very much :]

    Posted

  • Feylin by Feylin

    http://s3.amazonaws.com/mwp-development/north/0.3x0.15_jpgs/GLM_05180-0018_mosaic_I24M1.jpg
    is this a planetary nebula??? Since it obviously shines, and nebula only reflect light, they don't shine for themselves... I think this is a star, possebly a "different" kind (but why aren't we asked to tag them then?) or maybe one that is very bright or something like that, I don't know but I see them a lot too.
    I thought planetary nebula where the slight hazes of red "mist", which are not as compact as fuzzy red objects (tough I've labeled them every time as one... 😕)

    People, I want to say that I'm very disappointed by the "dead-ness" of the forum here 😕 I hoped for some discussion, but I wonder if ANYONE ever checks out this place... months ago it was a thriving place, but now...
    Oh and IF the scientists/admins still read this: maybe its an idea to add more "points of interest" since I've also read about the yellowballs and have spotted quite a few of them. I tagged them as green knots, but now I decided to tag them as "other" since they are no green knots at all... and there are so many features out there I want to tag... but there is no name for it, only the uncontempting "other".

    Posted

  • KhalilaRedBird by KhalilaRedBird in response to Feylin's comment.

    I would call it a planetary nebula, based on the examples tagged in the GLIMPSE viewer (http://www.alienearths.org/glimpse/glimpse.php?x=0.0765&y=0.1645&z=100&t=100 or http://www.alienearths.org/glimpse/glimpse.php?x=-0.3412&y=-0.0599&z=100&t=100 )

    Feylin
    http://s3.amazonaws.com/mwp-development/north/0.3x0.15_jpgs/GLM_05180-0018_mosaic_I24M1.jpg
    is this a planetary nebula??? Since it obviously shines, and nebula only reflect light, they don't shine for themselves... I think this is a star, possebly a "different" kind (but why aren't we asked to tag them then?) or maybe one that is very bright or something like that, I don't know but I see them a lot too.

    Posted

  • Feylin by Feylin

    ow... indeed. But those things look more like stars in my opinion. But if those are examples of planetary nebula, then I agree the pictures chelseanr posted actually DO depict planetary nebula.

    Posted

  • Ken_Koester by Ken_Koester

    If it has spikes, I think it is diffraction from a bright foreground object and not a nebula at all. I find it highly suspicious that all the planetary nebulae would have the same appearance, right down to the little "beads" in the outer ring.

    Snarkhunter

    Posted

  • broomrider1970 by broomrider1970

    So what are the objects then Ken? with the beads in the outer ring. So I can label them properly. 😄

    ~Bright Blessings
    Tina

    Posted

  • Ken_Koester by Ken_Koester

    I think this is just the physics of light warping around the supports of the mirror mechanisms in the scope. At least that is what it would be in a visible light scope. Haven't looked at how IR scopes do their thing, so this could be something else. But if you Wiki planetary nebula, you see images that look nothing at all like this--including one which does have several spikey objects & one bona fide planetary in the middle of the view. The others are definitely stars. Wiki says that only about 20% of planetaries are symmetrical, whereas all these things are, and that they all have to be at least 40M yr old. they are associated with the final stage of low(er) mass stars, not star births. Sure, you get stars dying young in these regions, but those are massive ones that supernova--they don't resemble the spikeys either.

    I've just been ignoring them until a mission specialist tells me otherwise, or unless they really seem associated with something else, in which case I just box everything around it.

    O yeah--Wiki also says that there are only about 3200 planetaries in the MW. We'd have spotted a fair number of them by now if these were they!

    Snarkhunter

    Posted

  • broomrider1970 by broomrider1970

    O Okay, I guess I've got to either rename the category or delete it completely. Haha! Thank you for the info. Even if it won't remain in the brain long, at least I will remember not to file them! 😉

    Posted

  • universehunter by universehunter

    What do you suppose they are then? They are a very interesting object and I see them fairly often.

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  • skendrew by skendrew scientist, admin

    Sorry I haven't commented on this before. This particular object is a type of star called OH/IR. OH/IR stars are cooler evolved stars - the 'OH' stands for the OH molecule, hydroxyl, which gets excited in the envelopes of these stars so we can its signature very brightly at radio wavelengths, and 'IR' stands for infrared, where they are also very bright, as you can see in these images. These stars tend to pulsate and lose material from their envelopes, that's why they looks a little like a compact nebula.

    Posted