Star Wheel may be positioned where you can not see it, That sure looks like a self adjuster to me.
Two suggestions.. I have a neat little flexible LED flashlight It has about a six inch flexible "neck" with the LED on the end, Batteries Plus sells them so do some electronics places (Where I got mine).
Using it I can direct light at odd angles and actualy reach INTO a brake assembly via the adjuster port.
Check to see if the star wheel is either 1: Between the two (Suspect it is) or 2: At the far end of the one where you see the screw (That is the far from the middle) or just beyond the far end.