SCYON Abstract

Received on June 4 2007

AKARI observations of circumstellar dust in the globular clusters NGC 104 and NGC 362

Authors	Yoshifusa Ita (¹), Toshihiko Tanabe (²), Noriyuki Matsunaga (²), Yoshikazu Nakada (²), Mikako Matsuura (³), Takashi Onaka (⁴), Hideo Matsuhara (¹), Takehiko Wada (¹), Naofumi Fujishiro (⁵), Daisuke Ishihara (⁴), Hirokazu Kataza (¹), Woojung Kim (¹), Toshio Matsumoto (¹), Hiroshi Murakami (¹), Youichi Ohyama (¹), Fumihiko Usui (¹), Shinki Oyabu (¹), Itsuki Sakon (⁴), Toshinobu Takagi (¹), Kazunori Uemizu (¹), Munetaka Ueno (⁶), and Hidenori Watarai (⁷)
Affiliation	(¹) Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Kanagawa, Japan (²) Institute of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo, Japan (³) National Astronomical Observatory of Japan, Mitaka, Tokyo, Japan (⁴) Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo, Japan (⁵) Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo, Japan (⁶) Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan (⁷) Office of Space Applications, Japan Aerospace Exploration Agency, Ibaraki, Japan
Accepted by	Publication of the ASJ
Contact	yita@ir.isas.jaxa.jp
URL	http://arxiv.org/abs/0706.0045
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Abstract

We report preliminary results of AKARI observations of two globular clusters, NGC 104 and NGC 362. Imaging data covering areas of about 10x10 arcmin² centered on the two clusters have been obtained with InfraRed Camera (IRC) at 2.4, 3.2, 4.1, 7.0, 9.0, 11.0, 15.0, 18.0 and 24.0 mu. We used F11/F2 and F24/F7 flux ratios as diagnostics of circumstellar dust emission. Dust emissions are mainly detected from variable stars obviously on the asymptotic giant branch, but some variable stars that reside below the tip of the first-ascending giant branch also show dust emissions. We found eight red sources with F24/F7 ratio greater than unity in NGC 362. Six out of the eight have no 2MASS counterparts. However, we found no such source in NGC 104.