We present spatially resolved (0.″1–1.″0) radio maps of Neptune taken from the Very Large Array and Atacama Large Millimeter/submillimeter Array between 2015 and 2017. Combined, these observations probe from just below the main methane cloud deck at ∼1 bar down to the NH₄SH cloud at ∼50 bar. Prominent latitudinal variations in the brightness temperature are seen across the disk. Depending on wavelength, the south polar region is 5–40 K brighter than the mid-latitudes and northern equatorial region. We use radiative transfer modeling coupled to Markov Chain Monte Carlo methods to retrieve H₂S, NH₃, and CH₄ abundance profiles across the disk, though only strong constraints can be made for H₂S. Below all cloud formation, the data are well fit by and protosolar enrichment in the H₂S and NH₃ abundances, respectively, assuming a dry adiabat. Models in which the radio-cold mid-latitudes and northern equatorial region are supersaturated in H₂S are statistically favored over models following strict thermochemical equilibrium. H₂S is more abundant at the equatorial region than at the poles, indicative of strong, persistent global circulation. Our results imply that Neptune's sulfur-to-nitrogen ratio exceeds unity, as H₂S is more abundant than NH₃ in every retrieval. The absence of NH₃ above 50 bar can be explained either by partial dissolution of NH₃ in an ionic ocean at GPa pressures or by a planet formation scenario in which hydrated clathrates preferentially delivered sulfur rather than nitrogen onto planetesimals, or a combination of these hypotheses.

我们展示了 2015 年至 2017 年间从超大阵列和阿塔卡马大型毫米/亚毫米阵列中获取的海王星空间分辨率 (0.″1–1.″0) 射电图。综合起来，这些观测是从主要甲烷云层下方探测的约 1 bar 到约50 bar的 NH ₄ SH 云。在整个圆盘上都可以看到亮度温度的显着纬度变化。根据波长的不同，南极地区比中纬度和赤道北部地区亮 5-40 K。我们使用与马尔可夫链蒙特卡罗方法相结合的辐射传输模型来检索整个磁盘上的H ₂ S、NH ₃和 CH ₄丰度剖面，尽管只能对 H ₂进行强约束S.下面所有云的形成，该数据是由良好适应和原太阳富集在H ₂ S和NH _3倍的丰度，分别，假设干绝热线。无线电寒冷的中纬度地区和赤道北部地区在 H ₂ S 中过饱和的模型在统计上优于遵循严格热化学平衡的模型。赤道地区的H ₂ S 比两极地区的更丰富，表明全球环流强劲、持续。我们的结果意味着海王星的硫氮比超过了 1，因为在每次检索中H ₂ S 比 NH ₃更丰富。不存在 NH ₃高于 50 bar 的压力可以通过 NH ₃在 GPa 压力下的离子海洋中部分溶解来解释，也可以通过行星形成场景来解释，其中水合包合物优先将硫而不是氮输送到微星上，或者这些假设的组合。