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DOI | 10.1029/2018GL078211 |
Saturn's Northern Aurorae at Solstice From HST Observations Coordinated With Cassini's Grand Finale | |
Lamy, L.1; Prange, R.1; Tao, C.2; Kim, T.3; Badman, S. V.4; Zarka, P.1; Cecconi, B.1; Kurth, W. S.5; Pryor, W.6; Bunce, E.7; Radioti, A.8 | |
2018-09-28 | |
发表期刊 | GEOPHYSICAL RESEARCH LETTERS |
ISSN | 0094-8276 |
EISSN | 1944-8007 |
出版年 | 2018 |
卷号 | 45期号:18页码:9353-9362 |
文章类型 | Article |
语种 | 英语 |
国家 | France; Japan; USA; England; Belgium |
英文摘要 | Throughout 2017, the Hubble Space Telescope (HST) observed the northern far-ultraviolet aurorae of Saturn at northern solstice, during the Cassini Grand Finale. These conditions provided a complete viewing of the northern auroral region from Earth and a maximal solar illumination, expected to maximize the ionosphere-magnetosphere coupling. We analyze 24 HST images concurrently with Cassini measurements of Saturn's kilometric radiation and solar wind parameters predicted by two magnetohydrodynamic models. The aurorae reveal highly variable components, down to timescales of minutes, radiating 7 to 124 GW. They include a nightside-shifted main oval, unexpectedly frequent and bright cusp emissions, and a dayside low-latitude component. On average, these emissions display a strong local time dependence with two maxima at dawn and premidnight, the latter being newly observed and attributed to nightside injections possibly associated with solstice conditions. These results provide a reference frame to analyze Cassini in situ measurements, whether simultaneous or not. Plain Language Summary In 2017, the Hubble Space Telescope regularly observed the northern ultraviolet aurorae of Saturn in coordination with Cassini in situ measurements obtained during the Grand Finale, when the spacecraft flew across magnetic field lines connected to the aurorae. Hubble imaged Saturn's aurorae at 24 occasions spread over 7months during northern solstice, when the northern auroral region was both fully visible from Earth and permanently illuminated by the Sun. The observed aurorae display a variety of components observed poleward of 68 degrees latitude with different properties, some of which were unreported before. These emissions strongly vary with time, down to a few minutes, and radiate from 7 to 124 GW. On average, the auroral intensity also strongly varies with local time (a Sun-referenced frame) and peaks at dawn, as previously observed, and also premidnight, pointing to a recurrent nightside activity of the magnetosphere. These results provide a reference basis to analyze Cassini in situ measurements. |
英文关键词 | aurora radio emissions Saturn magnetosphere solar wind |
领域 | 气候变化 |
收录类别 | SCI-E |
WOS记录号 | WOS:000447761300003 |
WOS关键词 | WIND DYNAMIC PRESSURE ; SOLAR-WIND ; KILOMETRIC RADIATION ; RADIO ; DEPENDENCE ; PLASMA ; EARTH |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/26033 |
专题 | 气候变化 |
作者单位 | 1.Univ Paris Diderot, UPMC, CNRS, LESIA,Observ Paris,PSL, Meudon, France; 2.Natl Inst Informat & Commun Technol, Tokyo, Japan; 3.Univ Alabama, Ctr Space Plasma & Aeronom Res, Huntsville, AL 35899 USA; 4.Univ Lancaster, Dept Phys, Lancaster, England; 5.Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA; 6.Cent Arizona Coll, Dept Sci, Coolidge, AZ USA; 7.Univ Leicester, Dept Phys & Astron, Leicester, Leics, England; 8.Space Sci Technol & Astrophys Res Inst, Liege, Belgium |
推荐引用方式 GB/T 7714 | Lamy, L.,Prange, R.,Tao, C.,et al. Saturn's Northern Aurorae at Solstice From HST Observations Coordinated With Cassini's Grand Finale[J]. GEOPHYSICAL RESEARCH LETTERS,2018,45(18):9353-9362. |
APA | Lamy, L..,Prange, R..,Tao, C..,Kim, T..,Badman, S. V..,...&Radioti, A..(2018).Saturn's Northern Aurorae at Solstice From HST Observations Coordinated With Cassini's Grand Finale.GEOPHYSICAL RESEARCH LETTERS,45(18),9353-9362. |
MLA | Lamy, L.,et al."Saturn's Northern Aurorae at Solstice From HST Observations Coordinated With Cassini's Grand Finale".GEOPHYSICAL RESEARCH LETTERS 45.18(2018):9353-9362. |
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