I noticed the following graphic being used in an article discussing the Voyager probes. It also appears on Wikipedia's Heliosphere page:
The same page states that:
On a broader scale, the motion of the heliosphere through the fluid medium of the ISM results in an overall comet-like shape. The solar wind plasma which is moving roughly "upstream" (in the same direction as the Sun's motion through the galaxy) is compressed into a nearly-spherical form, whereas the plasma moving "downstream" (opposite the Sun's motion) flows out for a much greater distance before giving way to the ISM, defining the long, trailing shape of the heliotail.
And that makes sense in terms of the overall shape being elliptical. However the proportions in the graphic suggest that the heliosphere's longest span (measured from the sun to heliopause) is at least 10 times as long as its shortest span. Notably (perhaps?) the Termination Shock is only shown as being very slightly elliptical in shape.
Does the sun's motion through the ISM really produce such a significant distortion, or is the graphic not accurately depicting the proportions involved?