HST has a unique capability to detect tenuous debris disks and exosolar planets at optical wavelengths. Using the ACS/HRC in 2004-2006, we imaged the debris belt surrounding Fomalhaut, finding evidence for a planetary system in the structure of the belt, and then directly imaging a planet candidate, Fomalhaut b. New STIS data recover Fomalhaut b in 2010 with the expected flux and near its expected position. We also discover a tenuous belt halo extending 30 AU beyond the previously measured outer belt edge, demonstrating that the belt structure is more complex than initially assumed. We propose a GO program dedicated to the study of Fomalhaut b's orbit and structure in the belt. The goals are to constrain the orbital elements of Fomalhaut b and establish with confidence that it is bound. The proposed astrometry is designed to measure the eccentricity with sufficient precision to discriminate between a circular orbit and one that is nested within the belt with e ~ 0.12. STIS is the only instrument that is demonstrably capable of making these astrometric observations. Moreover, we propose to build a high signal-to-noise image of the belt by combining the proposed Cycle 20 data with those obtained from previous cycles. The Fomalhaut system is of general interest to the community, particularly for studying the dynamical evolution of planetary systems relative to their outer planetesimal belts. Given its proximity (7.7 pc), Fomalhaut's belt is a rare example where we can resolve disk structure on sub-AU scales. The proposed additional STIS observations are critical for discerning between real astrophysical features and instrumental noise. These Visits duplicate STIS observations conducted under GO-11818 during September 2010 (Visits 19-21) and GO-12576 during May, 2012 (Visits 01-12). The star Fomalhaut will be imaged behind the STIS WEDGE. ORIENTs are chosen so that Fomalhaut b, which is at PA=318 approximately 13" from the star, is imaged in a region free of diffraction spikes, focal plane structures, etc. Obtaining a relatively stable PSF between orbits is critical for subtraction of the PSF and the detection of Fomalhaut b. One aim is to execute the observations in a sequence that is not interrupted by other observations or calibration programs. We have implemented GROUP WITHIN constraints so that four orbits at a time are observed consecutively. Ideally, all 12 orbits are executed in the minimum time frame that is feasible. One way to improve this program is if two guide stars can be made available. EXTRA-SOLAR PLANETS 12 false false 0.0 0.0 false false false SUPPORTED STAR A0-A3 V-IV This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 STIS/CCD Imaging Yes No WEDGEA2.5 Timing link suitability includes constraints ([Group (01 02 03 04) Within 0.2 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "01" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 18:53:00.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (01 02 03 04) Within 0.2 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "02" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:06:35.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (01 02 03 04) Within 0.2 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "03" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:06:47.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (01 02 03 04) Within 0.2 days] [05 After 04 by 0.0 to 1.5 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "04" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:07:07.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (05 06 07 08) Within 0.2 days] [05 After 04 by 0.0 to 1.5 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "05" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:09:56.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (05 06 07 08) Within 0.2 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "06" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:09:58.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (05 06 07 08) Within 0.2 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "07" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:10:00.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "07" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (05 06 07 08) Within 0.2 days] [09 After 08 by 0.0 to 1.5 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "08" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:10:03.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "08" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (09 10 11 12) Within 0.2 days] [09 After 08 by 0.0 to 1.5 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "09" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:10:06.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "09" :obset-id "09" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "09" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (09 10 11 12) Within 0.2 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "10" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:10:08.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "10" :obset-id "10" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "10" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (09 10 11 12) Within 0.2 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "11" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:10:10.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "11" :obset-id "11" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "11" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Group (09 10 11 12) Within 0.2 days]) The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13037 :visit-id "12" :proposal-version -1 :trans-version "20120604" :date "09-Jul-2012 19:10:12.0" :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 515696 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13037 :visit-id "12" :obset-id "12" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13037 :visit-id "12" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 439 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0