Jupiter's main auroral oval observed with HST-STIS

[1] An extended series of FUV images obtained on 7 days during winter 2000–2001, with fixed pointing, yielded highly accurate tracking of emisson features as Jupiter rotated. They provided newly detailed measurements of the degree of corotation of auroral emissions and their variations with changing central meridian longitude. This 2-month data set provides a statistical average location of the auroral emission and leads to the definition of new “reference ovals.” The overall auroral morphology pattern is shown to be fixed in System-III longitude and unchanged over a 5-year period. When arranged in central meridian longitude ranges, the images show a significant contraction of the northern main oval as the central meridian longitude increases from 115 to 255°. The main auroral oval brightness is globally very stable in comparison with its terrestrial counterpart. It is shown to vary with magnetic local time, increasing from noon to dusk and then decreasing again in the magnetic evening. Hectometric emissions observed simultaneously with Galileo and Cassini reveal interplanetary shocks propagating outward from the Sun which may be related to the contraction of the main auroral oval observed in the HST images taken on 14 December 2000. In addition, we find that a brightening and a significant contraction of the main oval observed on 13 January 2001 corresponded to a time of increased solar wind dynamic pressure.

[1]  Philippe Zarka,et al.  Detailed study of FUV Jovian auroral features with the post-COSTAR HST faint object camera , 1998 .

[2]  Christopher T. Russell,et al.  Location and shape of the Jovian magnetopause and bow shock , 1998 .

[3]  N. Achilleos,et al.  On the Dynamics of the Jovian Ionosphere and Thermosphere. III. The Modelling of Auroral Conductivity , 2002 .

[4]  P. Feldman,et al.  IUE observations of longitudinal and temporal variations in the Jovian auroral emission , 1984 .

[5]  D. Strobel,et al.  Overview of the Voyager ultraviolet spectrometry results through Jupiter encounter , 1981 .

[6]  W. Harris,et al.  Analysis of Jovian Auroral H Ly-α Emission (1981–1991) , 1996 .

[7]  V. Vasyliūnas,et al.  The magnetic anomaly model of the Jovian magnetosphere: Predictions for Voyager , 1979 .

[8]  Norbert Krupp,et al.  Particle bursts in the Jovian magnetosphere: Evidence for a near‐Jupiter neutral line , 2002 .

[9]  Emma J. Bunce,et al.  Modulation of Jupiter's main auroral oval emissions by solar wind induced expansions and compressions of the magnetosphere , 2003 .

[10]  H. W. Moos,et al.  Jovian ultraviolet auroral activity, 1981-1991 , 1992 .

[11]  G. Millward,et al.  On the Dynamics of the Jovian Ionosphere and Thermosphere: I. The Measurement of Ion Winds , 2001 .

[12]  J. Nichols,et al.  Magnetosphere-ionosphere coupling currents in Jupiter's middle magnetosphere: dependence on the effective ionospheric Pedersen conductivity and iogenic plasma mass outflow rate , 2003 .

[13]  David J. Southwood,et al.  A new perspective concerning the influence of the solar wind on the Jovian magnetosphere , 2001 .

[14]  T. Hill,et al.  The Jovian auroral oval , 2001 .

[15]  P. Louarn,et al.  Control of Jupiter's radio emission and aurorae by the solar wind , 2002, Nature.

[16]  E. Bunce,et al.  Local time asymmetry of the equatorial current sheet in Jupiter's magnetosphere , 2001 .

[17]  Emma J. Bunce,et al.  Modulation of Jovian middle magnetosphere currents and auroral precipitation by solar wind-induced compressions and expansions of the magnetosphere: Initial response and steady state , 2003 .

[18]  J. H. Waite,et al.  Ultraviolet emissions from the magnetic footprints of Io, Ganymede and Europa on Jupiter , 2002, Nature.

[19]  R. McNutt,et al.  Plasma bulk flow in Jupiter's dayside middle magnetosphere , 1988 .

[20]  J. H. Waite,et al.  Hubble Space Telescope imaging of Jupiter's UV aurora during the Galileo orbiter mission , 1998 .

[21]  J. Blamont,et al.  Extreme Ultraviolet Observations from Voyager 1 Encounter with Jupiter , 1979, Science.

[22]  J. Gérard,et al.  Simulation of the Morphology of the Jovian UV North Aurora Observed with the Hubble Space Telescope , 1997 .

[23]  Alan M. Watson,et al.  Time-Resolved Observations of Jupiter's Far-Ultraviolet Aurora , 1996, Science.

[24]  Denis Grodent,et al.  A self‐consistent model of the Jovian auroral thermal structure , 2001 .

[25]  Emma J. Bunce,et al.  Origin of the main auroral oval in Jupiter's coupled magnetosphere–ionosphere system , 2001 .

[26]  S. Krimigis,et al.  Leakage of energetic particles from Jupiter's dusk magnetosphere: Dual spacecraft observations , 2002 .

[27]  V. Vasyliūnas,et al.  Plasma distribution and flow , 1983 .

[28]  R Prange,et al.  HST far-ultraviolet imaging of Jupiter during the impacts of comet Shoemaker-Levy 9 , 1995, Science.

[29]  Renée Prangé,et al.  More about the structure of the high latitude Jovian aurorae , 2000 .

[30]  J. Walsh,et al.  STIS Geometric Distortion - SMOV3A tests for CCD, NUV- MAMA and FUV-MAMA , 2001 .

[31]  Emma J. Bunce,et al.  Jupiter's polar ionospheric flows: Theoretical interpretation , 2003 .

[32]  J. Connerney,et al.  New models of Jupiter's magnetic field constrained by the Io flux tube footprint , 1998 .

[33]  M. Kivelson,et al.  The dusk flank of Jupiter's magnetosphere , 2002, Nature.

[34]  E. Bunce,et al.  Divergence of the equatorial current in the dawn sector of Jupiter's magnetosphere: analysis of Pioneer and Voyager magnetic field data , 2001 .

[35]  T. Hill,et al.  Jovian auroral signature of Io's corotational wake , 2002 .

[36]  J. Gérard,et al.  Spatially Resolved Far Ultraviolet Spectroscopy of the Jovian Aurora , 2002 .

[37]  J. H. Waite,et al.  A pulsating auroral X-ray hot spot on Jupiter , 2002, Nature.

[38]  J. H. Waite,et al.  An auroral flare at Jupiter , 2001, Nature.

[39]  A. Lane,et al.  Observations from earth orbit and variability of the polar aurora on Jupiter , 1980 .

[40]  Denis Grodent,et al.  Jupiter's polar auroral emissions , 2003 .

[41]  E. Bunce,et al.  Distributions of current and auroral precipitation in Jupiter's middle magnetosphere computed from steady-state Hill–Pontius angular velocity profiles: solutions for current sheet and dipole magnetic field models , 2002 .

[42]  D. Williams,et al.  Global flows of energetic ions in Jupiter's equatorial plane: First‐order approximation , 2001 .

[43]  J. Dungey Interplanetary Magnetic Field and the Auroral Zones , 1961 .

[44]  J. Gérard,et al.  The morphology of the north Jovian ultraviolet aurora observed with the Hubble Space Telescope , 1994 .

[45]  Krishan K. Khurana,et al.  Influence of solar wind on Jupiter's magnetosphere deduced from currents in the equatorial plane , 2001 .

[46]  T. Hill Corotation Lag in Jupiter's Magnetosphere: Comparison of Observation and Theory , 1980, Science.

[47]  A. Vasavada,et al.  Jupiter's visible aurora and Io footprint , 1999 .

[48]  J. Trauger,et al.  Hubble Space Telescope far-ultraviolet imaging of Jupiter during the impacts of Comet Shoemaker-Levy 9 , 1995 .

[49]  J. H. Waite,et al.  A Remarkable Auroral Event on Jupiter Observed in the Ultraviolet with the Hubble Space Telescope , 1994, Science.

[50]  J. Holtzman,et al.  Far-Ultraviolet Imaging of Jupiter's Aurora and the Io “Footprint” , 1996, Science.

[51]  Peter A. Delamere,et al.  Excitation of the FUV Io tail on Jupiter: Characterization of the electron precipitation , 2002 .

[52]  T. Hill,et al.  Planetary spin period acceleration of particles in the Jovian magnetosphere , 1976 .

[53]  J. Blamont,et al.  Extreme Ultraviolet Observations from Voyager 2 Encounter with Jupiter , 1979, Science.