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 signicant 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 signicant 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⊕. This result suggests that the disks around Chamaeleon WTTSs are already evolved to debris disks.

ABSTRACT
1. CIRCUMSTELLAR DISKS
2. TARGET SOURCES
3. Results
    3.1. Individual Sources
    3.2. Stacking Analysis
4. SUMMARY AND FUTURE WORKS
REFERENCES

• Satoshi Takita(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency)
• Yasuo Doi(Department of Earth Science and Astronomy, The University of Tokyo)
• Ko Arimatsu(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency/Department of Astronomy, Graduate School of Science, The University of Tokyo)
• Takafumi Ootsubo(Department of Earth Science and Astronomy, The University of Tokyo)
• AKARI Team