由西南研究学院的斯科特·博尔顿（Scott Bolton）领导的NASA的JUNO任务正在改写科学家认为他们对木星的了解的知识，而一般的天然气巨人则重写。Sciencepapers released today. The Juno spacecraft has been in orbit around Jupiter since July 2016, passing within 3,000 miles of the equatorial cloudtops.
“What we’ve learned so far is earth-shattering. Or should I say, Jupiter-shattering,” said Bolton, Juno’s principal investigator. “Discoveries about its core, composition, magnetosphere, and poles are as stunning as the photographs the mission is generating.”
The solar-powered spacecraft’s eight scientific instruments are designed to study Jupiter’s interior structure, atmosphere, and magnetosphere. Two instruments developed and led by SwRI are working in concert to study Jupiter’s auroras, the greatest light show in the solar system. The Jovian Auroral Distributions Experiment (JADE) is a set of sensors detecting the electrons and ions associated with Jupiter’s auroras. The Ultraviolet Imaging Spectrograph (UVS) examines the auroras in UV light to study Jupiter’s upper atmosphere and the particles that collide with it. Scientists expected to find similarities to Earth’s auroras, but Jovian auroral processes are proving puzzling.
“Although many of the observations have terrestrial analogs, it appears that different processes are at work creating the auroras,” said SwRI’s Dr. Phil Valek, JADE instrument lead. “With JADE we’ve observed plasmas upwelling from the高层气氛to help populate Jupiter’s magnetosphere. However, the energetic particles associated with Jovian auroras are very different from those that power the most intense auroral emissions at Earth.”
Also surprising, Jupiter’s signature bands disappear near its poles. JunoCam images show a chaotic scene of swirling storms up to the size of Mars towering above a bluish backdrop. Since the first observations of these belts and zones many decades ago, scientists have wondered how far beneath the gas giant’s swirling façade these features persist. Juno’s microwave sounding instrument reveals that topical weather phenomena extend deep below the cloudtops, to pressures of 100 bars, 100 times Earth’s air pressure at sea level.
“但是，有一个南北的不对称性。乐队的深度分布不平等。”博尔顿说。“我们在赤道上观察到了狭窄的富含氨的羽流。它类似于从地球赤道上升并产生贸易风的更深，更广泛的气流。”
Juno is mapping Jupiter’s gravitational and magnetic fields to better understand the planet’s interior structure and measure the mass of the core. Scientists think a dynamo—a rotating, convecting, electrically conducting fluid in a planet’s outer core—is the mechanism for generating the planetary magnetic fields.
博尔顿说：“ Juno的重力场测量与我们的预期有很大不同，这对内部繁重元素的分布具有影响，包括木星核心的存在和质量。”观察到的磁场的幅度为7.766高斯，明显高于预期。但是真正的惊喜是该领域的急剧空间变化，这显着高于某些位置的预期，而在其他地方则明显低。“我们表征了该场以估计发电机区域的深度，这表明它可能发生在压力诱导的金属状态的上方的分子氢层中。”
这些初步科学结果在特别版的两篇论文中发表Science. Bolton is lead author of “Jupiter’s interior and deep atmosphere: The initial pole-to-pole passes with the Juno spacecraft.” SwRI’s Dr. Frederic Allegrini, Dr. Randy Gladstone, and Valek are co-authors of “Jupiter’s magnetosphere and aurorae observed by the Juno spacecraft during its first polar orbits”; lead author is Dr. John Connerney of the Space Research Corporation.
Juno是根据NASA的新边境计划开发的第二项任务。第一个是SWRI-LED New Horizons Mission，该任务在2015年7月为冥王星系统提供了首次历史性的景象，现在正朝着Kuiper Belt的新目标前进。NASA位于加利福尼亚州帕萨迪纳的NASA喷气推进实验室管理了SWRI的Bolton首席研究员Juno任务。丹佛的洛克希德·马丁（Lockheed Martin）建造了航天器。意大利航天局贡献了红外光谱仪仪器和无线电科学实验的一部分。
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