サガワ ヒデオ   SAGAWA HIDEO
  佐川 英夫
   所属   京都産業大学  理学部 宇宙物理・気象学科
   職種   教授
言語種別 英語
発行・発表の年月 2010/07
形態種別 研究論文
査読 査読あり
標題 First results of Herschel-PACS observations of Neptune
執筆形態 その他
掲載誌名 Astronomy & Astrophysics
出版社・発行元 EDP SCIENCES S A
巻・号・頁 518,pp.L152
著者・共著者 Lellouch, E,t,al,incl,Sagawa
概要 We report on the initial analysis of a Herschel-PACS full range spectrum of Neptune, covering the 51-220 mu m range with a mean resolving power of similar to 3000, and complemented by a dedicated observation of CH4 at 120 mu m. Numerous spectral features due to HD (R(0) and R(1)), H2O, CH4, and CO are present, but so far no new species have been found. Our results indicate that (i) Neptune's mean thermal profile is warmer by similar to 3 K than inferred from the Voyager radio-occultation; (ii) the D/H mixing ratio is (4.5 +/- 1) x 10(-5), confirming the enrichment of Neptune in deuterium over the protosolar value (similar to 2.1 x 10(-5)); (iii) the CH4 mixing ratio in the mid stratosphere is (1.5 +/- 0.2) x 10(-3), and CH4 appears to decrease in the lower stratosphere at a rate consistent with local saturation, in agreement with the scenario of CH4 stratospheric injection from Neptune's warm south polar region; (iv) the H2O stratospheric column is (2.1 +/- 0.5) x 10(14) cm(-2) but its vertical distribution is still to be determined, so the H2O external flux remains uncertain by over an order of magnitude; and (v) the CO stratospheric abundance is about twice the tropospheric value, confirming the dual origin of CO suspected from ground-based millimeter/submillimeter observations.
DOI 10.1051/0004-6361/201014600
ISSN 0004-6361/1432-0746