Various disk structures are marked

Various disk structures are marked. The green dotted contours mark the boundaries of the disk; the small circle at the center roughly marks the location of the star; the two green solid contours represent the extent of the two bright clumps; the solid, dotted and dashed white arcs trace out the inner, middle, and outer rings, respectively; and the arrow points out the spiral arm. The resolution (beam size, ~6.5 AU) of the image is labeled at the lower left corner.