The composition of the Jovian atmosphere as determined by the Galileo probe mass spectrometer.
The composition of the Jovian atmosphere as determined by the Galileo probe mass spectrometer.
复制标题
DOI：
10.1029/98je01050
复制
发表时间：
1998-09
影响因子：
--
通讯作者：
H. Niemann;H. Niemann;S. Atreya;G. Carignan;T. Donahue;J. Haberman;D. Harpold;R. Hartle;D. Hunten;W. Kasprzak;P. Mahaffy;T. Owen;S. Way
中科院分区：
文献类型：
--
作者：
H. Niemann;H. Niemann;S. Atreya;G. Carignan;T. Donahue;J. Haberman;D. Harpold;R. Hartle;D. Hunten;W. Kasprzak;P. Mahaffy;T. Owen;S. Way
伽利略号探测器质谱仪测定了木星大气中质量在2到150 amu之间的物质的组成，从0.5到21.1巴。本文介绍了一些组分的分析结果：H_2、He、Ne、Ar、Kr、Ar、CH_4、NH_3、H_2O、H_2S、C_2和C_3非甲烷烃，可能还有PH_3和Cl。木星大气中的He/H2为0.157 +/- 0.030。测得~（13）C/C ~（12）为0.0108 ± 0.0005，并测量了D/H和~ 3 He/~ 4 He。Ne为亏损态，≤ 0.13太阳能，Ar ≤ 1.7太阳能，Kr ≤ 5太阳能，Kr ≤ 5太阳能。CH 4具有（2.1 +/-0.4）× 10（-3）（12 ℃，2.9太阳能）的恒定混合比，其中混合比是相对于H2的。H2O混合比的上限从压力<3.8巴时的8 x 10（-7）上升到11.7巴时的（5.6 +/- 2.5）x 10（-5）（16 O，0.033 +/- 0.015太阳能），暂时在18.7巴时大了一个数量级。H2S的混合比在小于3.8巴的压力下为<10（-6），但从8.7巴下的约0.7 X 10（-5）上升至15巴以上的约7.7 X 10（-5）（32 S，2.5太阳能）。目前仅设定了非常大的NH3混合比上限。如果PH 3和Cl存在，它们的混合比也随压力增加。在适用于C2和C3烃的质量峰处检测到物质。目前尚不清楚其中哪些是大气成分，哪些是仪器产生的。这些测量结果意味着：（1）4 He的分馏;（2）可凝结物的局部高度依赖性损耗，可能是因为探测器进入了循环细胞的下降臂;（3）冰冷的微行星对挥发性物质的存量做出了重大贡献，（4）在过去的4.6 Gyr中，这部分星系的D/H有适度的降低，但（D +3 He）/H没有可检测到的变化。
The Galileo probe mass spectrometer determined the composition of the Jovian atmosphere for species with masses between 2 and 150 amu from 0.5 to 21.1 bars. This paper presents the results of analysis of some of the constituents detected: H2, He, Ne, Ar, Kr, Xe, CH4, NH3, H2O, H2S, C2 and C3 nonmethane hydrocarbons, and possibly PH3 and Cl. 4He/H2 in the Jovian atmosphere was measured to be 0.157 +/- 0.030. 13C/C12 was found to be 0.0108 +/- 0.0005, and D/H and 3He/4He were measured. Ne was depleted, < or = 0.13 times solar, Ar < or = 1.7 solar, Kr < or = 5 solar, and Xe < or = 5 solar. CH4 has a constant mixing ratio of (2.1 +/- 0.4) x 10(-3) (12C, 2.9 solar), where the mixing ratio is relative to H2. Upper limits to the H2O mixing ratio rose from 8 x 10(-7) at pressures <3.8 bars to (5.6 +/- 2.5) x 10(-5) (16O, 0.033 +/- 0.015 solar) at 11.7 bars and, provisionally, about an order of magnitude larger at 18.7 bars. The mixing ratio of H2S was <10(-6) at pressures less than 3.8 bars but rose from about 0.7 x 10(-5) at 8.7 bars to about 7.7 x 10(-5) (32S, 2.5 solar) above 15 bars. Only very large upper limits to the NH3 mixing ratio have been set at present. If PH3 and Cl were present, their mixing ratios also increased with pressure. Species were detected at mass peaks appropriate for C2 and C3 hydrocarbons. It is not yet clear which of these were atmospheric constituents and which were instrumentally generated. These measurements imply (1) fractionation of 4He, (2) a local, altitude-dependent depletion of condensables, probably because the probe entered the descending arm of a circulation cell, (3) that icy planetesimals made significant contributions to the volatile inventory, and (4) a moderate decrease in D/H but no detectable change in (D + 3He)/H in this part of the galaxy during the past 4.6 Gyr.