0 Assigned ID: 3288 ----- Attempting Submission 1 (Fri Mar 25 15:47:41 GMT 2022) ----- HST Phase I Proposal 3288 successfully submitted. Receipt: # 3288-1 ----- Attempting Submission 2 (Fri Mar 25 23:50:32 GMT 2022) ----- HST Phase I Proposal 3288 successfully submitted. Receipt: # 3288-2 ----- Attempting Submission 3 (Fri Mar 25 23:59:05 GMT 2022) ----- 0 ----- Attempting Submission 1 (Thu Jul 07 23:18:39 GMT 2022) ----- Astrometric search for Planets orbiting the closest Y Dwarf Located at 2.2 pc, the ~250K Y2 (sub-)brown dwarf WISE J085510.83-071442.5 is the fourth closest known system to Earth. Studying this object provides unique insights into brown dwarf (and exoplanet) atmospheric properties, thermal evolution, multiplicity, and planet-hosting prospects. We propose to use HST to obtain one the most accurate annual parallax of this - or any - planetary-mass brown dwarf to date, achieving an unprecedented accuracy of 200 micro-arcseconds, and constraining its absolute space motion to equivalent accuracy. More importantly, we will be able to search for faint companions co-moving with the target, either resolved or through astrometric perturbations of its linear motion, the latter probing down to a few Earth masses. HST is the optimal facility for precision astrometric measurement of WISE 0855-0714, as this source is too cool and faint at optical and near-infrared wavelengths to observe with ground-based facilities or Gaia. Our observations will improve current astrometric precision of this source by a factor of 40 and anchor future JWST measurements of this and other cold brown dwarfs, while providing high-precision distance and motion measurements and tight constraints on planetary-mass companions for one of the closest ``stellar object'' to the Sun. This is an astrometric project. Dr. Luigi Bedin (PI, INAF-OAPD) is an expert on imaging photometry and astrometry with HST under-sampled images, and has contributed to state of the art calibrations and corrections of HST data, linking HST astrometry to Gaia reference system at sub-mas level. Dr. Bedin will coordinate planning and data reduction, contribute to analysis, lead publication of results, and manage the overall program. Dr. Luigi R. Bedin have led the development and application of precision astrometric techniques with HST/WFC3 for low-temperature brown dwarfs Bedin & Fontanive 2018, MNRAS, 481, 5339; Bedin & Fontanive 2020, MNRAS, 494, 2068. He will lead analysis to extract precision astrometric measurements, and astrometric parameters. Bedin et al. 2017, MNRAS, 470, 1140. Prof. Adam Burgasser (PI, UCSD) is an expert on the discovery, spectral characterization and multiplicity of the lowest-mass stars and brown dwarfs. He PI'd two successful HST programs examining the multiplicity of T dwarfs. Prof. Burgasser will contribute to the scientific interpretation and analysis of the data. Burgasser et al. 2003, ApJ, 586, 512; Burgasser et al. 2006; ApJS, 166, 585. Prof. Daniel Apai (U. Arizona) is an expert on brown dwarf leading several HST/WFC3 and ground-based programs to characterize brown dwarf and exoplanet atmospheric structures and to search for extrasolar planets. Prof. Apai will contribute to the scientific interpretation of the data. Apai et al. 2017, Science, 357, 683 Apai et al 2016, ApJ, 820, 40. Dr. Clemence Fontanive (U. of Bern) specialises in the multiplicity statistics of the coldest and lowest-mass brown dwarfs and is the PI of successful HST programs searching for planetary-mass companions around low-mass brown dwarfs. Particularly GO-16229 which does astrometry for other Y dwarfs, and GO-15201 which does a photometric search for planetary mass companions around T and Y BDs. Dr. Fontanive will contribute to the scientific interpretation of the data. Fontanive et al. 2018, MNRAS, 479, 2702 Fontanive et al. 2020, ApJ Letter, 905, 14 Fontanive et al. 2021, MNRAS, 501, 911 Exoplanets and Exoplanet Formation Stellar Physics and Stellar Types 6 false false false false false false false SUPPORTED STAR BROWN DWARF NO This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 J=24.8 WFC3/IR Imaging No No F160W /home/bedin/PROPOSALs/Cy30/1.W0855b/PhII/OP-cache/PhII_17080-v01.xml The scheduling data was generated by CASM 30.3. 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CASM was run in Phase II mode. around May 10th, 2023 (Tic-Visit :proposal-id 17080 :visit-id "02" :proposal-version -1 :trans-version "20220516" :date "08-Jul-2022 01:12:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 3046560 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17080 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17080 :visit-id "02" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2700 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17080 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2696 :al-overhead-at-end 0 :internal-dur-at-end 652 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) true 2 0