What needs to be replaced on this cooktop?

My tenants can't cook on this Thermador because it looks like the burner cap covers are missing.
Does anyone have an idea of what I would need to replace to make this functional? The Thermador replacements I find are star shaped but I don't think that is what goes here.
Might be cheaper to replace with a different unit!
Thanks in advance

via What needs to be replaced on this cooktop?
by triciaintexas