The Io UV footprint (IFP) is an auroral emission on Jupiter consisting of one or more spots resulting from the electromagnetic interaction between Io and the Jovian magnetosphere. Recent UV HST observations of the Jovian aurora raised new issues and put previous interpretations under question. Dedicated STIS Time-tag observations based on only 3 HST orbits will help us to directly answer the following questions and test new hypothesis on the physics driving their associated phenomenon. The proposed observations will determine whether the previously observed short timescale (~2 min) variations of the IFP are periodic or burst events. If the (quasi-)periodicity is established, these constraints will help us to understand the origin of these variations. These observations will also clarify the conditions of occurrence of the unexpected quasi-simultaneous variations of the southern multiple spots of the IFP. Moreover, we propose to observe the emergence of the southern leading (or precursor) spot and the possible evolution of its brightness. These two elements might validate or exclude the recently proposed idea that cross-hemisphere electron beams or strong non-linearities of the electromagnetic interaction explain the presence of the leading and secondary spots.

This program consists of 3 STIS FUV-MAMA timetag sequences dedicated to the study of the variability of the Io auroral footprint (IFP) on Jupiter's southern hemisphere. In order to avoid buffer overflows, only a restricted part of the planetary disk (i.e. 35-45%) should appear on the image. Since the size of the planetary disk is related to the HST-Jupiter distance, the precise offset will require small corrections depending on the observation date. Moreover, offsets leading to Io footprint features hidden by the reppeller wire shadow should also be avoided. Consequently, the final pointing offset will be determined with the Contact Scientist or the Program Coordinator once the HST orbit dates are known with sufficient accuracy. SOLAR SYSTEM 12 false 0.0 0.0 false false false false false false SUPPORTED SOLAR SYSTEM This target is for observations of UV emissions from Jupiter's south polar region. The offset position is such that the south polar quadrant of Jupiter lies in the 25x25 arc sec STIS FUV MAMA field of view. The area of the planet disc in the FOV is limited to 35-45% so that the total counting rate due to reflected sunlight is less than 20,000 c/s. Moreover, one should avoid placing the Io footprint features just under the repeller wire shadow. We will need to interact with the CS/PS to set the appropriate pointing offset once potential observing dates have been released. PLANET OFFSET JUPITER STD=JUPITER TYPE=POS_ANGLE,RAD=23,ANG=158,REF=NORTH OLG OF IO BETWEEN 130 200, CML OF JUPITER FROM IO BETWEEN 90 120 EARTH SOLAR SYSTEM This target is for observations of UV emissions from Jupiter's south polar region. The offset position is such that the south polar quadrant of Jupiter lies in the 25x25 arc sec STIS FUV MAMA field of view. The area of the planet disc in the FOV is limited to 35-45% so that the total counting rate due to reflected sunlight is less than 20,000 c/s. Moreover, one should avoid placing the Io footprint features just under the repeller wire shadow. We will need to interact with the CS/PS to set the appropriate pointing offset once potential observing dates have been released. PLANET OFFSET JUPITER STD=JUPITER TYPE=POS_ANGLE,RAD=23,ANG=175,REF=NORTH OLG OF IO BETWEEN 110 185, CML OF JUPITER FROM IO BETWEEN 140 175 EARTH SOLAR SYSTEM This target is for observations of UV emissions from Jupiter's south polar region. The offset position is such that the south polar quadrant of Jupiter lies in the 25x25 arc sec STIS FUV MAMA field of view. The area of the planet disc in the FOV is limited to 35-45% so that the total counting rate due to reflected sunlight is less than 20,000 c/s. Moreover, one should avoid placing the Io footprint features just under the repeller wire shadow. We will need to interact with the CS/PS to set the appropriate pointing offset once potential observing dates have been released. PLANET OFFSET JUPITER STD=JUPITER TYPE=POS_ANGLE,RAD=23,ANG=175,REF=NORTH OLG OF IO BETWEEN 115 185, CML OF JUPITER FROM IO BETWEEN 175 215 EARTH STIS/FUV-MAMA Imaging No No F25SRF2 STIS/FUV-MAMA Imaging No No F25SRF2 STIS/FUV-MAMA Imaging No No F25SRF2 Using ephemeris for target 11649-01-JUPITER-SOUTH-1 ephemeris data for target 11649-01-JUPITER-SOUTH-1 does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 08.220 to 10.182. ephemeris interval: 08.156 to 10.149 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. Target defintions are time-specific. BETWEEN can be changed if necessary, but the target definitions would need to be changed to match. (Tic-Visit :proposal-id 11649 :visit-id "01" :proposal-version -1 :trans-version "20090130" :date "01-Jul-2009 08:11:37.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 1948304 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11649 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11649 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2863.0 :al-overhead-at-end 0 :internal-dur-at-end 442.0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) false 1 0 Using ephemeris for target 11649-02-JUPITER-SOUTH-2 ephemeris data for target 11649-02-JUPITER-SOUTH-2 does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 08.220 to 10.182. ephemeris interval: 08.154 to 10.151 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. Target defintions are time-specific. BETWEEN can be changed if necessary, but the target definitions would need to be changed to match. (Tic-Visit :proposal-id 11649 :visit-id "02" :proposal-version -1 :trans-version "20080609" :date "30-Jun-2008 13:57:54.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 1948304 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11649 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11649 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2903.0 :al-overhead-at-end 0 :internal-dur-at-end 442.0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) false 1 0 Using ephemeris for target 11649-03-JUPITER-SOUTH-3 ephemeris data for target 11649-03-JUPITER-SOUTH-3 does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 08.220 to 10.182. ephemeris interval: 08.154 to 10.151 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. Target defintions are time-specific. BETWEEN can be changed if necessary, but the target definitions would need to be changed to match. (Tic-Visit :proposal-id 11649 :visit-id "03" :proposal-version -1 :trans-version "20080609" :date "30-Jun-2008 13:55:30.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 1948304 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11649 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11649 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2903.0 :al-overhead-at-end 0 :internal-dur-at-end 442.0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) false 1 0