0 Assigned ID: 2012 ----- Attempting Submission 1 (Fri Apr 09 16:37:05 GMT 2021) ----- Visit 1670701 in a #<SEQ Observation-Blocks (01 02) WITHIN 01h25m44.000s> set which requires 5647.0 S Visit 1670702 in a #<SEQ Observation-Blocks (01 02) WITHIN 01h25m44.000s> set which requires 5647.0 S Made a small adjustment to optimize the ORIENT range in Visit 2. 898019083 ----- Attempting Submission 1 (Wed Jul 28 06:53:57 GMT 2021) ----- ----- Attempting Submission 2 (Tue Feb 22 23:17:33 GMT 2022) ----- We set the the WITHIN parameter to 0.9 orbit instead of 1.0 orbit in order to ensure that the orbits are executed consecutively. Precision astrometry with STIS to confirm the orbital motion of HD 106906b The 15 Myr old spectroscopic binary HD 106906 represents a unique laboratory for studying the early dynamical evolution of planetary systems because a gas giant exoplanet has been directly imaged exterior to a central planetary system and a distorted debris disk. Several groups have proposed that the planet has been ejected from its formation site near the binary and dynamically shapes the outer disk structure, much like the hypothetical Planet Nine in our solar system is thought to control the orbital architecture of detached Kuiper Belt Objects. A key test of this hypothesis is to measure the orbital elements of HD 106906b which requires exquisite astrometric precision over many years given its 737 au separation from the binary. Using multi-epoch HST imaging with ACS, WFC3 and STIS where background stars detected with Gaia are used as an astrometric reference frame, Nguyen et al. (2021) recently measured orbital motion and contrained the orbit of HD 106906b. The findings were consistent with the hypothesis that the planet perturbs the disk. However, the result strongly depends on a single ACS/HRC point from 2004 that cannot be reproduced given that the camera is no longer functional. Here we propose to reproduce their 2017 STIS observations in Cycle 29, five years after the planet was first imaged with STIS. The sky-plane motion over this interval is expected to be greater than 3-sigma of the astrometric uncertainty. These observations will serve as a critical validation using the same instrument for two epochs of astrometry and will refine the estimated posteriors of the planetary orbital elements. (1) To mitigate the effects of uncorrected geometric distortion, we aim to place HD 106906b in the central region of the STIS field. This is achieved by occulting the star at the WEDGEB1.8 position and using the specified ORIENTs. (2) HD 106906 is a bright star (mv = 7.8 mag) and its PSF halo interferes with the detection of its debris disk as well as the planet located at 7.1'' radius from the star. To achieve PSF subtraction we will image the science target at two roll angles. (3) We image at the WEDGEB1.8 position, and also at a POS-TARG X=-0.5" away from this position, thus achieving additional dithering for PSF analysis. (4) The best PSF subtractions occur when the the orbits are executed consecutively. Therefore, in Visit 01 we specify a timing SEQUENCE which should have consecutive orbits and not be interrupted by other types of observations. Prof. Paul Kalas specializes in the science of debris disks and exoplanets, with expertise in high-contrast imaging methods (observations, data reduction, and analysis) using all of HST's past and present imaging cameras. He has extensive experience designing large and long-term surveys, managing teams spread over multiple institutions, and mentoring graduate students and postdocs. Dr. Robert De Rosa is an expert in high-contrast imaging and data reduction. Meiji Nguyen specializes in using Gaia information and imaging astrometry to detect the orbital motions of directly detected exoplanets. Exoplanets and Exoplanet Formation 6 false false false false false false false SUPPORTED STAR DISK EXTRA-SOLAR PLANET EXTRA-SOLAR PLANETARY SYSTEM F3-F9 This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 STIS/CCD Imaging Yes No WEDGEB1.0 STIS/CCD Imaging Yes No WEDGEB1.0 Timing link suitability includes constraints ([Sequence (01 02) within 0.1 days]) The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16707 :visit-id "01" :proposal-version -1 :trans-version "20210514" :date "22-Feb-2022 15:11:18.0" :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 166048 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16707 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16707 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2932 :al-overhead-at-end 0 :internal-dur-at-end 379 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3389 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([Sequence (01 02) within 0.1 days]) The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16707 :visit-id "02" :proposal-version -1 :trans-version "20210514" :date "22-Feb-2022 15:11:19.0" :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 166048 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16707 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16707 :visit-id "02" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2932 :al-overhead-at-end 0 :internal-dur-at-end 379 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3389 :pcs-gap 0 ) true 1 0