Radio observations of comet 9P/Tempel 1 with the Australia Telescope facilities during the Deep Impact encounter |
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Authors: | P. A. Jones,J. M. Sarkissian,M. G. Burton,M. A. Voronkov, M. D. Filipovi |
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Affiliation: | Australia Telescope National Facility, PO Box 76, Epping, NSW 1710, Australia;School of Physics, University of New South Wales, Sydney 2052, Australia;Astro Space Centre, Profsouznaya st. 84/32, 117997 Moscow, Russia;University of Western Sydney, Locked Bag 1797, Penrith South, DC, NSW 1797, Australia |
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Abstract: | We present radio observations of comet 9P/Tempel 1 associated with the Deep Impact spacecraft collision of 2005 July 4. Weak 18-cm OH emission was detected with the Parkes 64-m telescope, in data averaged over July 4–6, at a level of 12 ± 3 mJy km s−1 , corresponding to OH production rate 2.8 × 1028 molecules s−1 (Despois et al. inversion model, or 1.0 × 1028 s−1 for the Schleicher & A'Hearn model). We did not detect the HCN 1–0 line with the Mopra 22-m telescope over the period July 2–6. The 3σ limit of 0.06 K km s−1 for HCN on July 4 after the impact gives the limit to the HCN production rate of <1.8 × 1025 s−1 . We did not detect the HCN 1–0 line, 6.7 GHz CH3OH line or 3.4-mm continuum with the Australia Telescope Compact Array (ATCA) on July 4, giving further limits on any small-scale structure due to an outburst. The 3σ limit on HCN emission of 2.5 K km s−1 from the ATCA around impact corresponds to limit < 4 × 1029 HCN molecules released by the impact. |
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Keywords: | comets: individual: 9P/Tempel 1 radio lines: Solar system |
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