17841( 2) - 13-Aug-2024 19:18:44 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17841 Version: 2 Check-in Time: 13-Aug-2024 19:18:44 STScI Edit Number: 0 Title Tracing the wobble: astrometric monitoring of the first Y+Y brown dwarf binary ------------------------------------------------------------------------------------ Type Cycle GO 32 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Clemence Fontanive Universite de Montreal Y CoI: Dr. Luigi R. Bedin INAF - Osservatorio Astronomico di Padova N CoI: Dr. Loic Albert Universite de Montreal N CoI: Dr. Matthew De Furio University of Texas at Austin N ------------------------------------------------------------------------------------ Abstract We propose a comprehensive astrometric follow-up of the first Y+Y brown dwarf binary, WISE 0336-0143 AB, a <1-AU separation and low mass ratio system detected with JWST. We aim to follow the ~50-mas astrometric wobble of the photocentre resulting from the binary orbital motion, by exploiting HST's high astrometric precision with WFC3/IR. Our program will accurately measure the system's proper motion, trigonometric parallax, and orbital configuration, at an unprecedented accuracy of <0.5 mas through asbolute astrometric calibrations using Gaia. Capitalising on the three archival HST epochs already available and the recent JWST results, we have a unique opportunity to simultaneously refine the system's distance and to measure the individual components' dynamical masses, by acquiring only four new HST epochs over the next two years. These additional carefully timed datasets are required to demarcate the absolute astrometric displacement of the barycentre and remaining on-sky offsets due to the orbital motion of the binary components around the centre of mass. This work will be crucial to anchor current and future observed characteristics of the unique WISE 0336-0143 benchmark, significantly contributing to our understanding of its fundamental and binary properties, and an important step forward in the characterisation and atmospheric modelling of Y-temperature giant exoplanets and brown dwarfs. In addition, this program will also pave the way for future investigations of sub-AU binary systems around faint Y dwarfs, and will provide us with an extensive dataset to develop a framework for joint astrometric analyses linking HST, JWST and Gaia data. ------------------------------------------------------------------------------------ Observations Description ------------------------ This multi-cycle program consists of 2 orbits of WFC3 IR channel imaging in Cycle 32 (complementing 2 orbits in Cycle 31) for precise astrometric monitoring of a newly discovered Y+Y brown dwarf binary. All orbits are planned as single-orbit visits. We apply large and fractional-pixel dithering patterns to allow both removal of hot pixels and increase the spatial resolution of the datasets. All observations are taken in full frame mode, in order to maximise the number of reference sources in the fields of view. 17841( 2) - 13-Aug-2024 19:18:44 - [ 2] Following the strategy from GO 16229 for the same target, adapted to fit within the shorter visibility windows with the new reduced gyro mode, we will acquire 2 F105W exposures and a set of 5 F160W images. The F105W images will be placed in the middle of the sequences, to avoid problems associated with contaminating scattered Earthlight at low limb angles at those wavekengths. We will use 302 s exposures in MULTIACCUM mode, with suitable sampling times and sequence to maximise to total exposure times. ------------------------------------------------------------------------------------ 17841( 2) - 13-Aug-2024 19:18:44 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 WISE0336-014 STAR, BROWN DWARF RA=03H36M5.0062S, J2000 H=22 3 DEC=-01D43'55.80" Reference Frame: ICRS Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2014.0 -0.017194523746510478 -1.2123 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 17841( 2) - 13-Aug-2024 19:18:44 - [ 4] Visit: 01 Visit Requirements: ON HOLD On Hold Comments: We request to wait until after the last orbit from this multi-cycle progam in Cycle 31 (GO-17466) is executed before scheduling the Cycle 32 visits. As justified in the proposal, the science results will be best optimised if we can schedule the latest visits based on preliminary results with the first two epochs of this program. Unfortunately visit#2 from GO-17466 has been delayed from August to November 2024, which means that we cannot take a preliminary look into what the best observing windows for the GO-17841 epochs might be. Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 WISE0336-01 WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG 7.34, 7.30; SEQ 43 CUM (302.938 1-7 NON-INT S) ------------------------------------------------------------------------------------------------------------------------------------ 2 WISE0336-01 WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG -5.34, -1.73 43 CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WISE0336-01 WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG -7.24, -7.16 43 CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WISE0336-01 WFC3/IR MULTIAC IR F105W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG 3.69, -3.57 43 CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 WISE0336-01 WFC3/IR MULTIAC IR F105W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG -3.59, 3.65 43 CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 WISE0336-01 WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG -1.69, -5.45 43 CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 WISE0336-01 WFC3/IR MULTIAC IR F160W NSAMP=14, SAMP-SEQ=SPARS25 1 DEF POS TARG 1.83, 5.50 43 CUM (327.939 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ WISE0336-0143 1 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM 17841( 2) - 13-Aug-2024 19:18:44 - [ 5] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ WISE0336-0143 2 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM WISE0336-0143 3 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM WISE0336-0143 4 WFC3/IR MULTIAC IR F105W none none none none 1 N/A CUM WISE0336-0143 5 WFC3/IR MULTIAC IR F105W none none none none 1 N/A CUM WISE0336-0143 6 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM WISE0336-0143 7 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM 17841( 2) - 13-Aug-2024 19:18:44 - [ 6] Visit: 02 Visit Requirements: ON HOLD On Hold Comments: We request to wait until after the last orbit from this multi-cycle progam in Cycle 31 (GO-17466) is executed before scheduling the Cycle 32 visits. As justified in the proposal, the science results will be best optimised if we can schedule the latest visits based on preliminary results with the first two epochs of this program. Unfortunately visit#2 from GO-17466 has been delayed from August to November 2024, which means that we cannot take a preliminary look into what the best observing windows for the GO-17841 epochs might be. Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 WISE0336-01 WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG 7.34, 7.30; SEQ 43 CUM (302.938 1-7 NON-INT S) ------------------------------------------------------------------------------------------------------------------------------------ 2 WISE0336-01 WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG -5.34, -1.73 43 CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WISE0336-01 WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG -7.24, -7.16 43 CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WISE0336-01 WFC3/IR MULTIAC IR F105W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG 3.69, -3.57 43 CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 WISE0336-01 WFC3/IR MULTIAC IR F105W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG -3.59, 3.65 43 CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 WISE0336-01 WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS25 1 DEF POS TARG -1.69, -5.45 43 CUM (302.938 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 WISE0336-01 WFC3/IR MULTIAC IR F160W NSAMP=14, SAMP-SEQ=SPARS25 1 DEF POS TARG 1.83, 5.50 43 CUM (327.939 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ WISE0336-0143 1 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM 17841( 2) - 13-Aug-2024 19:18:44 - [ 7] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ WISE0336-0143 2 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM WISE0336-0143 3 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM WISE0336-0143 4 WFC3/IR MULTIAC IR F105W none none none none 1 N/A CUM WISE0336-0143 5 WFC3/IR MULTIAC IR F105W none none none none 1 N/A CUM WISE0336-0143 6 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM WISE0336-0143 7 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM 17841( 2) - 13-Aug-2024 19:18:44 - [ 8] Summary Form for Proposal 17841 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=13, NSAMP=14, SAMP-SEQ=SPARS25 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ON HOLD , POS TARG -1.69, -5.45, POS TARG -3.59, 3.65, POS TARG -5.34, -1.73, POS TARG -7.24, -7.16, POS TARG 1.83, 5.50, POS TARG 3.69, -3.57, POS TARG 7.34, 7.30, SEQ 1-7 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F105W, F160W ------------------------------------------------------------------------------------------------------------------------------------ Target Names WISE0336-0143 ------------------------------------------------------------------------------------------------------------------------------------