16754( 4) - 29-Sep-2021 16:08:52 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16754 Version: 4 Check-in Time: 29-Sep-2021 16:08:52 STScI Edit Number: 1 Title Decoding the clouds on an irradiated inflated brown dwarf ------------------------------------------------------------------------------------ Type Cycle GO 29 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Sarah Casewell University of Leicester Y CoI: Dr. Stuart Littlefair University of Sheffield N CoI: Prof. Daniel Apai University of Arizona N CoI: Mr. Ben Wei Peng lew University of Arizona N CoI: Dr. Yifan Zhou University of Texas at Austin N CoI: Dr. Mark S. Marley University of Arizona N CoI: Dr. Xianyu Tan University of Oxford N CoI: Dr. Laura C Mayorga The Johns Hopkins University Applied N Physics Laboratory CoI: Dr. Vivien Parmentier University of Oxford N ------------------------------------------------------------------------------------ Abstract We propose HST time-resolved spectroscopy of a rare, eclipsing white dwarf-brown dwarf binary. The brown dwarf in the binary is a mid-L dwarf and is irradiated by its 10, 000 K white dwarf companion. The brown dwarf totally eclipses the white dwarf and the white dwarf parameters are well defined, meaning there is a directly measured radius of the brown dwarf, which is inflated compared to models of field dwarfs at the same age. As such this is the only inflated, irradiated cloudy L dwarf where atmospheric characterisation is possible, leading to insights into the processes occurring in the atmosphere. We will obtain phase resolved spectra between 1.1 and 1.7 microns using WFC3 with the G141 set up in time-series mode. We will combine our spectra with global circulation models and atmospheric models to: 1) Determine the effective temperature of the brown dwarf, 2) Study day-night heat redistribution in unprecedented detail 3) Determine if there are significant nightside clouds. HST can uniquely obtain the high-precision, time-resolved, near-infrared spectroscopy required by our science goals. ------------------------------------------------------------------------------------ Observations Description ------------------------ Observing Mode: The observations will use the WFC3/IR G141 instrument in time-series mode, similar to the observations performed for the similar systems in HST Program 15947. The instrument's high throughput from 1.1 to 1.7 microns, the remarkable sensitivity in the 1.4~m water absorption band, and the extraordinary photometric stability make WFC3/IR G141 the best and, indeed, the only choice to achieve our goals. Due to the relative faintness of the target, we will to 16754( 4) - 29-Sep-2021 16:08:52 - [ 2] conduct the observations in staring mode. We will use the sub256 array and SPARS25, NSAMP=15 setup, which resulting in a cadence of 313 seconds, and 25s for each non-destructive read. The light curves at this cadence will resolve the spectral modulations at sample rates greater than ten per brown dwarf orbit. We have specified 2 orient windows as we need to ensure light from a nearby, brighter star( J= 15.026 and H=14.4580) does not contaminate our data. We have specified orients so that the brighter star is well separated in the Y direction. Exposure Time Calculation and Signal-to-Noise Ratio Estimate: We estimate the required exposure times and SNR achieved using the WFC3 Exposure Time Calculator. For WD1032+011 we will achieve an SNR=216 in a single G141 exposure in white light. With 10 pixel-wide spectral bins, typical in exoplanet transmission spectroscopy, the average SNR in each bin will exceed 60. We calculated the SNR requirements on the basis of distinguishing spectral modulations assuming a difference between the day and nightside spectra of 4% and a J-band modulation amplitude of 2%. WD1032+011 has a precise period measurement and ephemeris from radial velocity and lightcurve measurements, allowing us to phase-fold the light curves, further increasing the precision. Reduced Gyro mode: We do not anticipate reduced gyro mode will affect this programme other than perhaps in reducing schedulability due to our Orient constraints. A smaller field of view is fine. ------------------------------------------------------------------------------------ 16754( 4) - 29-Sep-2021 16:08:52 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 2QZ-J103448. STAR, BROWN DWARF, DA RA=10H34M48.8350S, J2000 V = 19.2 z=19.29, Y=18.82, J=18.68, 9+005200 DEC=+00D52'1.68" H=18.20 Reference Frame: Other: SIMBAD Extended: NO Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 -0.006373663258326685 0.020327 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 16754( 4) - 29-Sep-2021 16:08:52 - [ 4] Visit: 01 Visit Requirements: PCS MODE FINE; GUID TOL 0.005"; GYRO MODE 3GOBAD; ORIENT 302.5D TO 62.5 D; ORIENT 122.5D TO 242.5 D; SEQ 01, 02, 03, 04, 05, 06 WITHIN 5.5 Orbits On Hold Comments: Additional Comments: 2 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 2QZ-J103448 WFC3/IR MULTIAC GRISM256 F127M NSAMP=5, SAMP-SEQ=SPARS10 1 DEF .9+005200 CUM (29.664 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 2QZ-J103448 WFC3/IR MULTIAC GRISM256 G141 NSAMP=15, SAMP-SEQ=SPARS25 8 DEF .9+005200 CUM (2504.979 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2QZ-J103448.9+00520 1 WFC3/IR MULTIAC GRISM256 F127M none none none none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 1 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 2 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 3 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 4 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 5 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 6 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 7 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 8 none 1 N/A 0 CUM 16754( 4) - 29-Sep-2021 16:08:52 - [ 5] Visit: 02 Visit Requirements: PCS MODE FINE; GUID TOL 0.005"; GYRO MODE 3GOBAD; SAME ORIENT AS 01 On Hold Comments: Additional Comments: 2 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 2QZ-J103448 WFC3/IR MULTIAC GRISM256 F127M NSAMP=5, SAMP-SEQ=SPARS10 1 DEF .9+005200 CUM (29.664 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 2QZ-J103448 WFC3/IR MULTIAC GRISM256 G141 NSAMP=15, SAMP-SEQ=SPARS25 8 DEF .9+005200 CUM (2504.979 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2QZ-J103448.9+00520 1 WFC3/IR MULTIAC GRISM256 F127M none none none none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 1 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 2 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 3 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 4 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 5 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 6 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 7 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 8 none 1 N/A 0 CUM 16754( 4) - 29-Sep-2021 16:08:52 - [ 6] Visit: 03 Visit Requirements: PCS MODE FINE; GUID TOL 0.005"; GYRO MODE 3GOBAD; SAME ORIENT AS 01 On Hold Comments: Additional Comments: 2 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 2QZ-J103448 WFC3/IR MULTIAC GRISM256 F127M NSAMP=5, SAMP-SEQ=SPARS10 1 DEF .9+005200 CUM (29.664 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 2QZ-J103448 WFC3/IR MULTIAC GRISM256 G141 NSAMP=15, SAMP-SEQ=SPARS25 8 DEF .9+005200 CUM (2504.979 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2QZ-J103448.9+00520 1 WFC3/IR MULTIAC GRISM256 F127M none none none none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 1 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 2 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 3 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 4 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 5 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 6 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 7 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 8 none 1 N/A 0 CUM 16754( 4) - 29-Sep-2021 16:08:52 - [ 7] Visit: 04 Visit Requirements: PCS MODE FINE; GUID TOL 0.005"; GYRO MODE 3GOBAD; SAME ORIENT AS 01 On Hold Comments: Additional Comments: 2 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 2QZ-J103448 WFC3/IR MULTIAC GRISM256 F127M NSAMP=5, SAMP-SEQ=SPARS10 1 DEF .9+005200 CUM (29.664 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 2QZ-J103448 WFC3/IR MULTIAC GRISM256 G141 NSAMP=15, SAMP-SEQ=SPARS25 8 DEF .9+005200 CUM (2504.979 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2QZ-J103448.9+00520 1 WFC3/IR MULTIAC GRISM256 F127M none none none none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 1 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 2 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 3 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 4 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 5 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 6 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 7 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 8 none 1 N/A 0 CUM 16754( 4) - 29-Sep-2021 16:08:52 - [ 8] Visit: 05 Visit Requirements: PCS MODE FINE; GUID TOL 0.005"; GYRO MODE 3GOBAD; SAME ORIENT AS 01 On Hold Comments: Additional Comments: 2 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 2QZ-J103448 WFC3/IR MULTIAC GRISM256 F127M NSAMP=5, SAMP-SEQ=SPARS10 1 DEF .9+005200 CUM (29.664 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 2QZ-J103448 WFC3/IR MULTIAC GRISM256 G141 NSAMP=15, SAMP-SEQ=SPARS25 8 DEF .9+005200 CUM (2504.979 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2QZ-J103448.9+00520 1 WFC3/IR MULTIAC GRISM256 F127M none none none none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 1 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 2 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 3 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 4 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 5 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 6 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 7 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 8 none 1 N/A 0 CUM 16754( 4) - 29-Sep-2021 16:08:52 - [ 9] Visit: 06 Visit Requirements: PCS MODE FINE; GUID TOL 0.005"; GYRO MODE 3GOBAD; SAME ORIENT AS 01 On Hold Comments: Additional Comments: 2 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 2QZ-J103448 WFC3/IR MULTIAC GRISM256 F127M NSAMP=5, SAMP-SEQ=SPARS10 1 DEF .9+005200 CUM (29.664 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 2QZ-J103448 WFC3/IR MULTIAC GRISM256 G141 NSAMP=15, SAMP-SEQ=SPARS25 8 DEF .9+005200 CUM (2504.979 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2QZ-J103448.9+00520 1 WFC3/IR MULTIAC GRISM256 F127M none none none none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 1 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 2 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 3 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 4 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 5 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 6 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 7 none 1 N/A 0 CUM 2QZ-J103448.9+00520 2 WFC3/IR MULTIAC GRISM256 G141 none none 8 none 1 N/A 0 CUM 16754( 4) - 29-Sep-2021 16:08:52 - [ 10] Summary Form for Proposal 16754 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures GRISM256 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=15, NSAMP=5, SAMP-SEQ=SPARS10, SAMP-SEQ=SPARS25 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GUID TOL 0.005", GYRO MODE 3GOBAD, ORIENT 122.5D TO 242.5 D, ORIENT 302.5D TO 62.5 D, PCS MODE FINE, SAME ORIENT AS 01, SEQ 01, 02, 03, 04, 05, 06 WITHIN 5.5 Orbits ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F127M, G141 ------------------------------------------------------------------------------------------------------------------------------------ Target Names 2QZ-J103448.9+005200 ------------------------------------------------------------------------------------------------------------------------------------