Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The red square nebula mwc 922

  1. Jul 27, 2011 #1

    Found this yesterday on dailygalaxy.com. explanation given is that this is ejecta of two cones from a central star, seen edgewise. I am not convinced by that explanation for several reasons. My first thought was that this looks remarkably like a hypercube or tesseract. I would be interested in hearing what other members of this forum think.

    Last edited by a moderator: Jul 27, 2011
  2. jcsd
  3. Jul 27, 2011 #2
    further web search, there is a similar object, The Red Rectangle nebula, HD 44179, very close, I think, to the directly opposite side of the sky. Simbad shows HD 44179 at right ascension 18:21:15.94 declination -10:39, and MWC 922 at right ascension 06:20.0 declination -13:01:27.1
  4. Jul 28, 2011 #3


    User Avatar
    Staff Emeritus
    Science Advisor

    The edge on view sounds like a logical explanation to me.
  5. Aug 4, 2011 #4
    You have to look at the pictures. If this is two ejecta cones, there are some unanswered questions. Notice that the ejecta cones are spreading out at an internal angle of 90 degrees. I have seen no other ejecta spread like that. What kind of ejection can result in such a wide spread? Also, notice that the end of the cone is flat.....so, either the cone is hollow (just try to explain that one) or else the outer edges of the cone are moving faster than the central material. If this really is an ejecta cone, the ends should be curved.
  6. Aug 4, 2011 #5


    User Avatar
    Gold Member

    Well, I note that, while most articles do not mention it, the central system seems to be a close binary.

    That could explain why this looks different from most other nebulae.

    Last edited: Aug 4, 2011
  7. Aug 5, 2011 #6
    yes, that is an excellent article, and thanks for the lead. I was interested in the torus explanation, which seems to me to attempt to answer the flat-ended cone question. However, if the structure were a torus on edge, would not the evacuated cones sides appear curved?
  8. Aug 5, 2011 #7


    User Avatar
    Gold Member

    Your idea that the outer edges must be curved assumes that the inner volume between the spikes must be filled .i.e. a volumetric cone. If the cone instead is empty, then there is no surface to be curved; we are seeing simply the surface of a hollow cone.

    An empty cone would occur formed if the structure is formed by two opposite jets, off the centre of rotation, sweeping out a circle.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook