Click on the thumbnail image to jump to the desired order of length magnitude: top-left is 1e6m, lower-right is 1e17m. (Image description)
Rigel and Aldebaran (top left and right) compared to smaller stars, the Sun (very small dot in lower middle, with orbit of mercury as yellow ellipse) and transparent sphere with radius of one light minute: click image for larger view and links to other scales.
^Richichi, A.; Roccatagliata, V. Aldebaran's angular diameter: How well do we know it?. Astronomy and Astrophysics, Volume 433, Issue 1, April I 2005, pp.305-312. "We derive an average value of 19.96±0.03 milliarcsec for the uniform disk diameter. The corresponding limb-darkened value is 20.58±0.03 milliarcsec, or 44.2±0.9 Rȯ."
^Richichi, A. and Roccatagliata, V. derived an angular diameter of 20.58±0.03 milliarcsec, which given a distance of 65 light years yields a diameter of 61 million km