Saturn's equinoctial auroras

J. D. Nichols; S. V. Badman; E. J. Bunce; J. T. Clarke; S. W. H. Cowley; F. J. Crary; M. K. Dougherty; J. C. Gérard; D. Grodent; K. C. Hansen; W. S. Kurth; D. G. Mitchell; W. R. Pryor; T. S. Stallard; D. L. Talboys; S. Wannawichian

doi:10.1029/2009GL041491

Saturn's equinoctial auroras

J. D. Nichols^*, S. V. Badman, E. J. Bunce, J. T. Clarke, S. W. H. Cowley, F. J. Crary, M. K. Dougherty, J. C. Gérard, D. Grodent, K. C. Hansen, W. S. Kurth, D. G. Mitchell, W. R. Pryor, T. S. Stallard, D. L. Talboys, S. Wannawichian

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

41 Citations (Scopus)

Abstract

[1] We present the first images of Saturn's conjugate equinoctial auroras, obtained in early 2009 using the Hubble Space Telescope. We show that the radius of the northern auroral oval is ∼1.5° smaller than the southern, indicating that Saturn's polar ionospheric magnetic field, measured for the first time in the ionosphere, is ∼17% larger in the north than the south. Despite this, the total emitted UV power is on average ∼17% larger in the north than the south, suggesting that field-aligned currents (FACs) are responsible for the emission. Finally, we show that individual auroral features can exhibit distinct hemispheric asymmetries. These observations will provide important context for Cassini observations as Saturn moves from southern to northern summer.

Original language	English
Article number	L24102
Number of pages	5
Journal	Geophysical Research Letters
Volume	36
Issue number	24
Early online date	23 Dec 2009
DOIs	https://doi.org/10.1029/2009GL041491
Publication status	Published - Dec 2009
Externally published	Yes

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10.1029/2009GL041491

Cite this

Nichols, J. D., Badman, S. V., Bunce, E. J., Clarke, J. T., Cowley, S. W. H., Crary, F. J., Dougherty, M. K., Gérard, J. C., Grodent, D., Hansen, K. C., Kurth, W. S., Mitchell, D. G., Pryor, W. R., Stallard, T. S., Talboys, D. L., & Wannawichian, S. (2009). Saturn's equinoctial auroras. Geophysical Research Letters, 36(24), Article L24102. https://doi.org/10.1029/2009GL041491

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title = "Saturn's equinoctial auroras",

abstract = "[1] We present the first images of Saturn's conjugate equinoctial auroras, obtained in early 2009 using the Hubble Space Telescope. We show that the radius of the northern auroral oval is ∼1.5° smaller than the southern, indicating that Saturn's polar ionospheric magnetic field, measured for the first time in the ionosphere, is ∼17% larger in the north than the south. Despite this, the total emitted UV power is on average ∼17% larger in the north than the south, suggesting that field-aligned currents (FACs) are responsible for the emission. Finally, we show that individual auroral features can exhibit distinct hemispheric asymmetries. These observations will provide important context for Cassini observations as Saturn moves from southern to northern summer.",

author = "Nichols, {J. D.} and Badman, {S. V.} and Bunce, {E. J.} and Clarke, {J. T.} and Cowley, {S. W. H.} and Crary, {F. J.} and Dougherty, {M. K.} and G{\'e}rard, {J. C.} and D. Grodent and Hansen, {K. C.} and Kurth, {W. S.} and Mitchell, {D. G.} and Pryor, {W. R.} and Stallard, {T. S.} and Talboys, {D. L.} and S. Wannawichian",

year = "2009",

month = dec,

doi = "10.1029/2009GL041491",

language = "English",

volume = "36",

journal = "Geophysical Research Letters",

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T1 - Saturn's equinoctial auroras

AU - Nichols, J. D.

AU - Badman, S. V.

AU - Bunce, E. J.

AU - Clarke, J. T.

AU - Cowley, S. W. H.

AU - Crary, F. J.

AU - Dougherty, M. K.

AU - Gérard, J. C.

AU - Grodent, D.

AU - Hansen, K. C.

AU - Kurth, W. S.

AU - Mitchell, D. G.

AU - Pryor, W. R.

AU - Stallard, T. S.

AU - Talboys, D. L.

AU - Wannawichian, S.

PY - 2009/12

Y1 - 2009/12

N2 - [1] We present the first images of Saturn's conjugate equinoctial auroras, obtained in early 2009 using the Hubble Space Telescope. We show that the radius of the northern auroral oval is ∼1.5° smaller than the southern, indicating that Saturn's polar ionospheric magnetic field, measured for the first time in the ionosphere, is ∼17% larger in the north than the south. Despite this, the total emitted UV power is on average ∼17% larger in the north than the south, suggesting that field-aligned currents (FACs) are responsible for the emission. Finally, we show that individual auroral features can exhibit distinct hemispheric asymmetries. These observations will provide important context for Cassini observations as Saturn moves from southern to northern summer.

AB - [1] We present the first images of Saturn's conjugate equinoctial auroras, obtained in early 2009 using the Hubble Space Telescope. We show that the radius of the northern auroral oval is ∼1.5° smaller than the southern, indicating that Saturn's polar ionospheric magnetic field, measured for the first time in the ionosphere, is ∼17% larger in the north than the south. Despite this, the total emitted UV power is on average ∼17% larger in the north than the south, suggesting that field-aligned currents (FACs) are responsible for the emission. Finally, we show that individual auroral features can exhibit distinct hemispheric asymmetries. These observations will provide important context for Cassini observations as Saturn moves from southern to northern summer.

U2 - 10.1029/2009GL041491

DO - 10.1029/2009GL041491

M3 - Article

SN - 0094-8276

VL - 36

JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 24

M1 - L24102

ER -