AI 中文总结
研究结合朱诺号微波辐射计观测与贝叶斯框架，揭示木星深层气相碱金属与氯的丰度比，排除全球千巴辐射带，为木星吸积固体的岩-冰平衡提供新诊断依据。
AI 中文摘要
朱诺号微波辐射计（MWR）的最长波长通道通过钠和钾电离产生的自由电子探测木星的千巴级大气。在平衡化学条件下，电子丰度是碱金属阳离子与阴离子Cl⁻和HS⁻之间电荷平衡的微小残余。由于气态HCl会因NH₄Cl凝结从可观测大气中被去除，无法直接测量木星深层大气中的氯，而硫已被伽利略号探测器测量。因此，MWR-derived的电子测量约束的是碱金属与氯的比值，而非仅碱金属丰度。我们将MWR观测结果与平衡化学、微波辐射传输结合在贝叶斯框架中，发现0.3-5倍太阳氯丰度范围内，深层气相元素碱金属与氯的丰度比（Na+K）/Cl为0.05，约为原太阳比8.7的1/180。在3倍太阳氯丰度下，推断的碱金属金属丰度为1.6×10⁻²倍太阳（1σ：1.2×10⁻²-2.7×10⁻²倍太阳）；而在低氯丰度下，HS⁻设定的碱金属下限约为10⁻³倍太阳。推断的气相碱金属丰度超过~10⁻⁵倍太阳阈值两个数量级以上，排除了长期提出的全球千巴辐射带。由于钠和钾是难熔元素，而氯是挥发性元素，推断的比值为木星吸积固体中的岩-冰平衡提供了新的诊断依据。该成分解释假设平衡化学成立；若在非平衡条件下，上升的矿物云控制电子丰度，则推断的碱金属-氯关系可能不成立。
英文摘要
The longest-wavelength channel of the Juno Microwave Radiometer (MWR) probes Jupiter's kilobar atmosphere through free electrons produced by sodium and potassium ionization. Under equilibrium chemistry the electron abundance is the small residual of the charge balance between alkali cations and the anions Cl- and HS-. Chlorine is not directly measurable in Jupiter's deep atmosphere because gaseous HCl is removed from the observable atmosphere by NH4Cl condensation, whereas sulfur has been measured by the Galileo probe. The MWR-derived electron measurement therefore constrains the alkali-to-chlorine ratio rather than the alkali abundance alone. We combine the MWR observations with equilibrium chemistry and microwave radiative transfer in a Bayesian framework, finding that the deep gas-phase elemental alkali-to-chlorine abundance ratio is (Na+K)/Cl = 0.05 over 0.3-5 times solar in chlorine, about 180 times below the protosolar ratio of 8.7. At 3 times solar chlorine, the inferred alkali metallicity is 1.6 x 10^-2 times solar (1 sigma: 1.2 x 10^-2 - 2.7 x 10^-2 times solar), while at low chlorine abundance HS- sets an alkali floor near 10^-3 times solar. The inferred gas-phase alkali abundance exceeds the ~10^-5 times solar threshold by more than two orders of magnitude and rules out the long-proposed global kilobar radiative zone. Because sodium and potassium are refractory whereas chlorine is volatile, the inferred ratio provides a new diagnostic of the rock-to-ice balance in the solids accreted by Jupiter. This compositional interpretation assumes equilibrium chemistry; if lofted mineral clouds instead control the electron abundance under disequilibrium conditions, the inferred alkali-chlorine relationship need not hold.
Comments8 pages, 3 figures. Submitted to AAS Journals
