The nitrogen isotopic ratio in Jupiter's atmosphere from observations by the Composite Infrared Spectrometer on the Cassini spacecraft
The nitrogen isotopic ratio in Jupiter's atmosphere from observations by the Composite Infrared Spectrometer on the Cassini spacecraft
复制标题
DOI：
10.1086/381084
复制
发表时间：
2004-02-20
影响因子：
4.9
通讯作者：
Romani, PN
中科院分区：
文献类型：
--
作者：
Abbas, MM;LeClair, A;Romani, PN
卡西尼号航天器上的复合红外光谱仪（CIRS）在2000年12月至2001年1月飞越木星期间对木星大气层进行了红外观测。从观测中获得的600-1400 cm（-1）区域的独特数据库具有0.53和2.8 cm（-1）的光谱分辨率，可以检索木星大气的热结构和组成的全球地图，包括（NH 3）-N-14和（NH 3）-N-15的分布。分析木星的氨分布从三个孤立的（NH 3）-N-15谱线在八个纬度的氮同位素比值的评估。在这次分析中，木星大气中的氮同位素比率N-14/N-15（或N-15/N-14）计算为448 +/- 62 [或（2.23 +/- 0.31）x 10（-3）]。发现从CIRS数据确定的比率的这个值与先前从伽利略探针质谱仪的测量获得的值非常接近。一些可能的机制来解释木星观测到的同位素比相对于那些不同的天体物理环境的变化进行了讨论。
The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft made infrared observations of Jupiter's atmosphere during the flyby of 2000 December to 2001 January. The unique database in the 600-1400 cm(-1) region with 0.53 and 2.8 cm(-1) spectral resolutions obtained from the observations permits retrieval of global maps of the thermal structure and composition of Jupiter's atmosphere, including the distributions of (NH3)-N-14 and (NH3)-N-15. Analysis of Jupiter's ammonia distributions from three isolated (NH3)-N-15 spectral lines in eight latitudes is presented for evaluation of the nitrogen isotopic ratio. The nitrogen isotopic ratio N-14/N-15 (or N-15/N-14) in Jupiter's atmosphere in this analysis is calculated to be 448 +/- 62 [or (2.23 +/- 0.31) x 10(-3)]. This value of the ratio determined from CIRS data is found to be in very close agreement with the value previously obtained from the measurements by the Galileo Probe Mass Spectrometer. Some possible mechanisms to account for the variation of Jupiter's observed isotopic ratio relative to those of various astrophysical environments are discussed.