January 29, 2010
Since the publication of our Science papers and the press conference last fall, you have probably noticed that we haven't been sending out IBEX updates every month. In this phase of the mission we thought we would send periodic, but less frequent updates covering the publication of new observations and our evolving understanding of the heliosphere's interstellar interaction. In order to help understand the discussion about various ideas that may be at the heart of the bright, unexpected ribbon that IBEX discovered, we developed the schematic diagram below. The IBEX spacecraft and instruments continue to work very well and the new observations of the second sky map we are building up are really stunning. Everything continues to go great—GO IBEX!
The IBEX science team and other scientists have been working hard to try to explain the mechanisms that are creating the unexpected “ribbon” feature seen in our first heliosphere maps. In our original Science papers, the team showed that the orientation of the ribbon seems to be driven by the direction of the local galactic magnetic field, and put forward six different ideas to account for this remarkable new feature. Periodically, we are publishing scientific papers that flesh out each of the ideas (and possibly even propose other, new ideas). Most recently, a paper by Dr. Jacob Heerikhuisen from the University of Alabama at Huntsville and other IBEX team members published a paper that explores one of our initial concepts (see idea 3 in the schematic).
None of the proposed models can fully account for the data that IBEX has collected. Each has its pros and cons that we are exploring and comparing. More maps taken from the IBEX spacecraft over the coming years are needed to test existing ideas and to develop more complex physical models that include all of the relevant effects. The possibility even exists that maps taken over time will show that none of the models are correct, or that a combination of effects is at work. The IBEX spacecraft continues to collect data, and a new set of maps of the heliosphere will be produced in a few months.
Brief explanations of each of the original six ideas/models are included below. Check them out, and see where our thoughts are right now. Stay tuned—much more is in store for IBEX!
So what ideas do the science team members have for explaining the ribbon?
Schematic diagram summarizing the six possible sources of the ribbon of enhanced ENA emissions in the IBEX data identified by McComas, et al. [2009b].
Hover over any of the ideas in the image above to get an explanation. Please note that some of the terminology above may be complex. Click on any of the highlighted words for a definition of that term. In addition, you can go to the Students
section of this website for more explanations of terminology, and go to the Planetaria
section for related downloadable educational materials.