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Unmanned Spaceflight.com _ Pluto / KBO _ Emily's KBO diagram

Posted by: ngunn Feb 17 2012, 08:49 PM

In this post Emily demonstrates an interesting way to depict the movements of Kuiper Belt objects: http://www.planetary.org/blog/article/00003381/

I like this diagram. It reminds me of lissajous figures on an oscilloscope screen in the case where the x and y signals have the same frequency but differing phase relationships. I agree with the idea of reducing the size of the objects' position and direction markers. Perhaps tiny triangles could serve in both capacities by being oriented to point along the 'orbits'. I would like to see Sedna included since the (so far) unique nature of its motion would stand out well. I think its trajectory during at least the second half of the 600 year timespan in question would fit on the diagram.

Posted by: elakdawalla Feb 17 2012, 10:05 PM

Ooh, the idea of just using triangles to represent the current positions of the objects is excellent.

Posted by: ngunn Feb 18 2012, 04:44 PM

One other suggestion. How about replacing heliocentric latitude with vertical distance above or below the ecliptic plane on the vertical axis (i.e. use z and r from cylindrical polar coordinates)? I think this would make the plot easier to grasp conceptually as it would then trace the actual shape of each orbit on a meridional plane swept through 360 degrees.

Posted by: Juramike Feb 18 2012, 05:07 PM

Trying to do the mental gymnastics here, but I think I really like Nigel's suggestion.

For objects further out there, a similar change in heliocentric latitude translates to a larger excursion from the ecliptic. So a diagram like Nigel suggested will do a better job of empasizing the difference. A diagram showing only heliocentric latitude will downplay it. (Because a far out object will have to have a massive excursion to get a big latitude shift.)


Posted by: ngunn Feb 18 2012, 07:07 PM

OK I could have been clearer. I'm suggesting plotting DsinLAT v DcosLAT instead of LAT v D. The rationale is that whilst still collapsing all longitudes to one plane, as in Emily's original, this would preserve everything else about the orbit's geometry without distortion.

Posted by: Leither Feb 18 2012, 08:02 PM

QUOTE (elakdawalla @ Feb 17 2012, 10:05 PM) *
Ooh, the idea of just using triangles to represent the current positions of the objects is excellent.


..but then you'd lose the relative sizes and shapes info. I'd keep the shapes just make them smaller. smile.gif

Posted by: remcook Feb 20 2012, 12:57 PM

Looks like another fun project!

Perhaps you could also add small tick marks (or black dots or something) every X years along the orbit to get a sense of time?

Posted by: elakdawalla Feb 21 2012, 05:48 AM

Today I fiddled around with the most common request, which was to see what the rest of the solar system would look like on this diagram. I tried it out with a logarithmic scale, but didn't like it. I think that the logarithmic one fails to provide an intuitive sense of the actual distances involved; it's very hard to read numbers off a logarithmic graph without making large mistakes. But the linear scale does crush the inner solar system practically into oblivion. Interestingly, though, the inner solar system makes sense at one linear scale, and the outer at a different one. I think the answer is to present the graph in two segments with different range scales, with Jupiter appearing on both. For right now I'm not interested in the asteroid belt -- figuring out the families of orbits etc. in that part of the solar system is a project for another day. So it's beneficial for now that it's crushed into oblivion!

The bodies that are on here are: the planets (black); the four largest asteroids (dark red); eight centaurs (green -- the ones listed on the Wikipedia centaur page -- I don't know if they're a representative sample or not); three Neptune Trojans (pink); and the eight biggest KBOs (blue).

 

Posted by: Eluchil Feb 27 2012, 03:44 PM

Thanks for the updated view. It's quite nice. What really stands out to me is how Jupiter dominates the system. That's partly an artifact of the classes of objects you picked (i.e. no Jupiter Trojans) , but I think the absence of non-resonant Jupiter crossers (as opposed to the Centaurs or NEO's) is real.

Posted by: cndwrld Feb 28 2012, 10:00 AM


I like your diagram, Emily. It just depends who your audience is, I guess. To me, it isn't intuitive. It is really nice, but requires some figuring out. And of course, making something obvious and intuitive is always the hard part. Plus, no single diagram works for everyone, so I could be in a minority.

I tried to put here a screen shot of one section of the Venus Express long term planning poster I use. We like to show relative positions using the standard orbit diagrams, Sun centric. It isn't fancy, or even accurate; but it is intuitive.



I was wondering about using a form of the orbit diagram, coupled with the orbit in different colors. One could show the orbits from above, to give you the relative distance from the Sun. To add a second dimension, you could color code the orbit ellipses to show relative distance from the ecliptic. If one used a spectrum, from minus-a-lot degrees through zero degrees to plus-a-lot degrees, going from red to green to blue, you might see more intuitively both how the eccentricity of the orbit changes as well as the distance from the ecliptic.

Pair that with a shot of the orbits taken from 'the side', in the ecliptic, showing the relative elevation of the orbits above the ecliptic. The two together, with duplicated information reinforcing each other, might make it more intuitive.

I hope the idea is clear. I also hope it isn't stupid. But I'd settle for just clear. Stupid ideas, I have lots of those.



Posted by: vikingmars Feb 10 2014, 11:48 PM

Emily wrote a very nice article in the last S&T issue : "Secrets of the Kuiper Belt".
It's summarizing very well our knowledge about those worlds with nice diagrams too...
Thanks a lot Emily smile.gif smile.gif smile.gif


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