18244( 2) - 30-Apr-2026 19:58:55 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18244 Version: 2 Check-in Time: 30-Apr-2026 19:58:55 STScI Edit Number: 0 Title A Definitive Transmission Survey of the Atmosphere of 55 Cnc e ------------------------------------------------------------------------------------ Type Cycle GO 33 ------------------------------------------------------------------------------------ Investigators Contact? PI: Victoria Abigail Boehm Cornell University Y CoI: Dr. Nikole Lewis Cornell University N CoI: Dr. Katy Chubb University of Bristol N CoI: Dr. Eva-Maria Ahrer Max Planck Institute for Astronomy N CoI: Ms. Ailsa Campbell University of Bristol N CoI: Dr. Beatriz Campos Estrada Max Planck Institute for Astronomy N CoI: Ms. Cinta Vidante Max Planck Institute for Astronomy N CoI: Dr. Lili Alderson Cornell University N CoI: Mr. Richard Donald Chatterjee University of Leeds N CoI: Elijah Mullens Cornell University N CoI: Dr. Harrison Nicholls University of Cambridge N CoI: Dr. Hannah Wakeford University of Bristol N ------------------------------------------------------------------------------------ Abstract We propose simultaneous observations of one transit of 55 Cnc e through JWST NIRISS/SOSS and HST WFC3/IR G141 to resolve inconsistencies in its atmospheric spectrum. JWST dayside emission studies have claimed detection of a high mean molecular weight (mmw) atmosphere rich in CO/CO2, at odds with HST transmission study claims of a low mmw atmosphere rich in H2 and HCN. Systematic differences between these instruments may be to blame, complicating efforts to interpret exoplanet atmospheres through multi-observatory studies. However, 55 Cnc e is a tidally-locked lava world with evidence for dayside variability, possibily originating from volcanic super-plumes or cloud condensation cycles. As a result, the contrasting results between JWST and HST may be astrophysical, and could yield the first evidence of spatial atmosphere variations due to extreme thermal and wind gradients, or the first evidence of transmission variability due to atmospheric and/or geologic activity. Our study leverages the observing power of both JWST and HST to confidently distinguish between all three of these scenarios, definitively revealing the true nature of this standout tidally-locked ultra-short-period super-Earth. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will observe the transiting lava world 55 Cnc e using the WFC3/IR G141. Our observation will consist of 4 HST orbits scheduled in a contiguous block. These observations should be scheduled to avoid the SAA and are phase constrained such that one HST orbit occurs during 55 Cnc e's transit, with two orbits pre-transit and one post-transit to measure the stellar baseline flux as well as characterize HST systematics so they may be corrected for. These observations are phase-constrained to start when 55 Cnc e is between orbital phases 0.7869-0.8278. These constraints are designed to capture one full orbit 18244( 2) - 30-Apr-2026 19:58:55 - [ 2] of in-transit flux while also maximizing the size of the starting window to facilitate scheduling. Per JWST-GO 12237, these observations must also be taken simultaneously with Visit 1 of JWST-GO 12237, which is phase-constrained to start slightly after HST-GO 18244 Visit 1 begins to account for the differences between HST and JWST detector settling timescales. The simultaneity of these observations will enable us to benchmark the performance of the new JWST NIRISS/SOSS multistripe readout mode against the performance of HST WFC3/IR G141, and detect or rule out spatial and/or temporal variability in the atmosphere of 55 Cnc e. Some adjustments have been made to the observing strategy of Visit 19 to accommodate the restrictions of reduced gyro mode. In particular, one iteration has been trimmed from the G141 spatial scans in Orbits 2, 3, and 4 to prevent orbital visibility overruns that would otherwise occur as a result of the increased time to reacquire the guide star in RGM. We have also adjusted the phase constraints based on updated ephemerides information and based on the requirements of our program to maximize in-transit flux. All four orbits include a "dummy exposure" at the end of the orbit, which use a different sampling sequence than our science exposures and which would incur orbital visibility overruns if executed. These exposures are not to be taken in practice and exist solely to force APT to trigger a buffer dump of the WFC3/IR during occultation of the target star, when it will have no impact on observations. We do request that the scheduled buffer dump occur in occultation as shown in the Orbit Planner. ------------------------------------------------------------------------------------ 18244( 2) - 30-Apr-2026 19:58:55 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 -RHO01-CNC STAR, EXTRA-SOLAR RA=08H52M35.8111S +/- 0.1", J2000 V = 26.6 V = 5.95084 +/- 0.02300 PLANET, EXTRA-SOLAR DEC=+28D19'50.95" +/- 0.1" PLANETARY SYSTEM, K V-IV Reference Frame: ICRS Comments: This star is in a binary system with the second component (55 Cancri B) being an M4 dwarf star with V-magnitude 13, separated by 1.4 arcminutes. Both components share proper motion. The star 53 Cancri is also nearby at 4.6 arcminutes away, with similar V-magnitude (6.3) to our target star. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -0.03678472643429209 -0.233517 0.0794482 ------------------------------------------------------------------------------------------------------------------------------------ 18244( 2) - 30-Apr-2026 19:58:55 - [ 4] Visit: 01 (55-CNC-e_G141_Transit) Visit Requirements: SCHED 100%; Period 0.7365474 D AND ZERO-PHASE HJD2457063.2096 On Hold Comments: Additional Comments: Per JWST-GO 12237, this observation is a duplication of Visit 19 in HST-GO 13665 and is requested to be taken simultaneously with Visit 1 of JWST-GO 12237. We require all four orbits in this visit to be taken contiguously with no interruptions, and to be scheduled to avoid the SAA. These observations are phase-constrained to begin when 55 Cnc e is between orbital phases 0.7869-0.8278 to ensure that Orbit 3 captures the maximal amount of in-transit flux. Some adjustments have been made to the observing strategy of Visit 19 to accommodate the restrictions of reduced gyro mode. In particular, one iteration has been trimmed from each 55-CNC-e Science exposure in Orbits 2, 3, and 4 to prevent orbital visibility overruns that would otherwise occur as a result of the increased time to reacquire the guide star in RGM. All four orbits include a "dummy exposure" at the end of the orbit. These exposures, labelled "Buffer Dump Trigger", contain a RAPID exposure containing the minimum number of samples needed to trigger a buffer dump to occur during occultation of the target. These exposures would incur 17 s of orbital visibility overrun in Orbit 1, and 144 s of overrun in Orbits 2, 3, and 4. In execution, we do not request these RAPID exposures actually be taken. We only include these to trigger APT to schedule a buffer dump during occultation. We do request that the in-occultation buffer dumps occur as scheduled to minimize the impact of the buffer dumps on the observations. 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 -RHO01-CNC WFC3/IR MULTIAC IRSUB512 F132N NSAMP=14, SAMP-SEQ=RAPID 1 DEF PHASE 0.7869 TO 0.8278; CUM (11.942 S) GS ACQ SCENARIO SINGLE; SAME GUIDE STARS 1-9; SEQ 1-3 NON-INT; SAME OBSET 1-3 ------------------------------------------------------------------------------------------------------------------------------------ 2 -RHO01-CNC WFC3/IR MULTIAC GRISM512 G141 NSAMP=2, SAMP-SEQ=SPARS10 15 DEF POS TARG -13.5, -36; CUM (263.242 SPATIAL SCAN 4.8, 90.0 S) Degrees, Round trip ------------------------------------------------------------------------------------------------------------------------------------ 3 -RHO01-CNC WFC3/IR MULTIAC GRISM512 G141 NSAMP=11, SAMP-SEQ=RAPID 1 DEF POS TARG -13.5, -36; CUM (18.767 S) SPATIAL SCAN 4.8, 90.0 Degrees, Round trip Comments: This is a dummy exposure that is not to be taken in execution. It is included here to force APT to trigger a WFC3/IR buffer dump during the occultation of the target star, so as to prevent loss of observing time due to buffer dumps. In practice, we request that the in-occultation buffer dump occur as scheduled but that this exposure be skipped. ------------------------------------------------------------------------------------------------------------------------------------ 18244( 2) - 30-Apr-2026 19:58:55 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 4 -RHO01-CNC WFC3/IR MULTIAC GRISM512 G141 NSAMP=2, SAMP-SEQ=SPARS10 16 DEF POS TARG -13.5, -36; CUM (280.791 SPATIAL SCAN 4.8, 90.0 S) Degrees, Round trip; SEQ 4-5 NON-INT; SAME OBSET 4-5 ------------------------------------------------------------------------------------------------------------------------------------ 5 -RHO01-CNC WFC3/IR MULTIAC GRISM512 G141 NSAMP=15, SAMP-SEQ=RAPID 1 DEF POS TARG -13.5, -36; CUM (25.591 S) SPATIAL SCAN 4.8, 90.0 Degrees, Round trip Comments: This is a dummy exposure that is not to be taken in execution. It is included here to force APT to trigger a WFC3/IR buffer dump during the occultation of the target star, so as to prevent loss of observing time due to buffer dumps. In practice, we request that the in-occultation buffer dump occur as scheduled but that this exposure be skipped. ------------------------------------------------------------------------------------------------------------------------------------ 6 -RHO01-CNC WFC3/IR MULTIAC GRISM512 G141 NSAMP=2, SAMP-SEQ=SPARS10 16 DEF POS TARG -13.5, -36; CUM (280.791 SPATIAL SCAN 4.8, 90.0 S) Degrees, Round trip; SEQ 6-7 NON-INT; SAME OBSET 6-7 ------------------------------------------------------------------------------------------------------------------------------------ 7 -RHO01-CNC WFC3/IR MULTIAC GRISM512 G141 NSAMP=15, SAMP-SEQ=RAPID 1 DEF POS TARG -13.5, -36; CUM (25.591 S) SPATIAL SCAN 4.8, 90.0 Degrees, Round trip Comments: This is a dummy exposure that is not to be taken in execution. It is included here to force APT to trigger a WFC3/IR buffer dump during the occultation of the target star, so as to prevent loss of observing time due to buffer dumps. In practice, we request that the in-occultation buffer dump occur as scheduled but that this exposure be skipped. ------------------------------------------------------------------------------------------------------------------------------------ 8 -RHO01-CNC WFC3/IR MULTIAC GRISM512 G141 NSAMP=2, SAMP-SEQ=SPARS10 16 DEF POS TARG -13.5, -36; CUM (280.791 SPATIAL SCAN 4.8, 90.0 S) Degrees, Round trip; SEQ 8-9 NON-INT; SAME OBSET 8-9 ------------------------------------------------------------------------------------------------------------------------------------ 18244( 2) - 30-Apr-2026 19:58:55 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 9 -RHO01-CNC WFC3/IR MULTIAC GRISM512 G141 NSAMP=15, SAMP-SEQ=RAPID 1 DEF POS TARG -13.5, -36; CUM (25.591 S) SPATIAL SCAN 4.8, 90.0 Degrees, Round trip Comments: This is a dummy exposure that is not to be taken in execution. It is included here to force APT to trigger a WFC3/IR buffer dump during the occultation of the target star, so as to prevent loss of observing time due to buffer dumps. In practice, we request that the in-occultation buffer dump occur as scheduled but that this exposure be skipped. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO01-CNC 1 WFC3/IR MULTIAC IRSUB512 F132N none none none none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 1 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 1 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 2 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 2 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 3 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 3 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 4 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 4 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 5 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 5 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 6 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 6 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 7 none 1 N/A CUM 18244( 2) - 30-Apr-2026 19:58:55 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 7 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 8 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 8 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 9 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 9 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 10 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 10 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 11 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 11 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 12 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 12 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 13 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 13 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 14 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 14 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 15 none 1 N/A CUM -RHO01-CNC 2 WFC3/IR MULTIAC GRISM512 G141 none none 15 none 1 N/A CUM -RHO01-CNC 3 WFC3/IR MULTIAC GRISM512 G141 none none none none 1 N/A CUM -RHO01-CNC 3 WFC3/IR MULTIAC GRISM512 G141 none none none none 1 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 1 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 1 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 2 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 2 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 3 none 2 N/A CUM 18244( 2) - 30-Apr-2026 19:58:55 - [ 8] 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 3 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 4 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 4 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 5 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 5 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 6 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 6 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 7 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 7 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 8 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 8 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 9 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 9 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 10 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 10 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 11 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 11 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 12 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 12 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 13 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 13 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 14 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 14 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 15 none 2 N/A CUM 18244( 2) - 30-Apr-2026 19:58:55 - [ 9] 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 15 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 16 none 2 N/A CUM -RHO01-CNC 4 WFC3/IR MULTIAC GRISM512 G141 none none 16 none 2 N/A CUM -RHO01-CNC 5 WFC3/IR MULTIAC GRISM512 G141 none none none none 2 N/A CUM -RHO01-CNC 5 WFC3/IR MULTIAC GRISM512 G141 none none none none 2 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 1 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 1 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 2 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 2 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 3 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 3 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 4 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 4 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 5 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 5 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 6 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 6 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 7 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 7 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 8 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 8 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 9 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 9 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 10 none 3 N/A CUM 18244( 2) - 30-Apr-2026 19:58:55 - [ 10] 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 10 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 11 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 11 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 12 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 12 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 13 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 13 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 14 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 14 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 15 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 15 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 16 none 3 N/A CUM -RHO01-CNC 6 WFC3/IR MULTIAC GRISM512 G141 none none 16 none 3 N/A CUM -RHO01-CNC 7 WFC3/IR MULTIAC GRISM512 G141 none none none none 3 N/A CUM -RHO01-CNC 7 WFC3/IR MULTIAC GRISM512 G141 none none none none 3 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 1 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 1 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 2 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 2 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 3 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 3 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 4 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 4 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 5 none 4 N/A CUM 18244( 2) - 30-Apr-2026 19:58:55 - [ 11] 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 5 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 6 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 6 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 7 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 7 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 8 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 8 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 9 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 9 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 10 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 10 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 11 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 11 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 12 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 12 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 13 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 13 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 14 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 14 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 15 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 15 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 16 none 4 N/A CUM -RHO01-CNC 8 WFC3/IR MULTIAC GRISM512 G141 none none 16 none 4 N/A CUM -RHO01-CNC 9 WFC3/IR MULTIAC GRISM512 G141 none none none none 4 N/A CUM 18244( 2) - 30-Apr-2026 19:58:55 - [ 12] 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO01-CNC 9 WFC3/IR MULTIAC GRISM512 G141 none none none none 4 N/A CUM 18244( 2) - 30-Apr-2026 19:58:55 - [ 13] Summary Form for Proposal 18244 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures GRISM512, IRSUB512 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=11, NSAMP=14, NSAMP=15, NSAMP=2, SAMP-SEQ=RAPID, SAMP-SEQ=SPARS10 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO SINGLE, PHASE 0.7869 TO 0.8278, POS TARG -13.5, -36, Period 0.7365474 D AND ZERO-PHASE HJD2457063.2096, SAME GUIDE STARS 1-9, SAME OBSET 1-3, SAME OBSET 4-5, SAME OBSET 6-7, SAME OBSET 8-9, SCHED 100%, SEQ 1-3 NON-INT, SEQ 4-5 NON-INT, SEQ 6-7 NON-INT, SEQ 8-9 NON-INT, SPATIAL SCAN 4.8, 90.0 Degrees, Round trip ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F132N, G141 ------------------------------------------------------------------------------------------------------------------------------------ Target Names -RHO01-CNC ------------------------------------------------------------------------------------------------------------------------------------