FIR View of Disks of Weak-Line T Tauri Stars

Abstract

We have observed ~60 Weak-line T Tauri stars (WTTSs) toward the Chamaeleon star forming region using the AKARI Far-Infrared Surveyor (FIS) All-Sky maps. We could not detect any significant emission from each source even at the most sensitive WIDE-S band. Then, we have performed stacking analysis of these WTTSs using the WIDE-S band images to improve the sensitivity. However, we could not detect any significant emission in the resultant image with a noise level of 0.05 MJy sr^-1, or 3 mJy for a point source. The three-sigma upper limit of 9~mJy leads to the disk dust mass of 0.01 M_{\oplus}. This result suggests that the disks around Chamaeleon WTTSs are already evolved to debris disks.