Poster title: First confirmation for the origin of spiral structures in the transitional disk around AB Aurigae.

Poster abstract: To investigate how spiral arms in transitional disks form, we conducted Subaru/HiCIAO PDI observations around 
AB Aur and compared the morphology of these new data against earlier epoch imagery obtained ~6 years ago. As a results, we 
confirmed the spiral arms do not change over time; this would be firm proof of structures induced by wide-orbit planet(s) at ≳100 
AU. I will report on these results.