DETECTION OF PARENT H{sub 2}O AND CO{sub 2} MOLECULES IN THE 2.5-5 {mu}m SPECTRUM OF COMET C/2007 N3 (LULIN) OBSERVED WITH AKARI
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)
- Kyoto Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555 (Japan)
- Department of Physics and Astronomy, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of)
- National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
- Hokkaido University of Education, Asahikawa Campus, Hokumon 9, Asahikawa, Hokkaido 070-8621 (Japan)
- Academia Sinica, Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China)
- Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States)
- Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
Comet C/2007 N3 (Lulin) was observed with the Japanese infrared satellite AKARI in the near-infrared at a post-perihelion heliocentric distance of 1.7 AU. Observations were performed with the spectroscopic (2.5-5.0 {mu}m) and imaging (2.4, 3.2, and 4.1 {mu}m) modes on 2009 March 30 and 31 UT, respectively. AKARI images of the comet exhibit a sunward crescent-like shape coma and a dust tail extended toward the anti-solar direction. The 4.1 {mu}m image (CO/CO{sub 2} and dust grains) shows a distribution different from the 2.4 and 3.2 {mu}m images (H{sub 2}O and dust grains). The observed spectrum shows distinct bands at 2.66 and 4.26 {mu}m, attributed to H{sub 2}O and CO{sub 2}, respectively. This is the fifth comet in which CO{sub 2} has been directly detected in the near-infrared spectrum. In addition, CO at 4.67 {mu}m and a broad 3.2-3.6 {mu}m emission band from C-H bearing molecules were detected in the AKARI spectrum. The relative abundance ratios CO{sub 2}/H{sub 2}O and CO/H{sub 2}O derived from the molecular production rates are {approx}4%-5% and <2%, respectively. Comet Lulin belongs to the group that has relatively low abundances of CO and CO{sub 2} among all observed comets.
- OSTI ID:
- 21451053
- Journal Information:
- Astrophysical Journal Letters, Vol. 717, Issue 1; Other Information: DOI: 10.1088/2041-8205/717/1/L66; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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