18432( 2) - 30-Jul-2026 19:52:25 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18432 Version: 2 Check-in Time: 30-Jul-2026 19:52:25 STScI Edit Number: 0 Title Anchoring Mass Loss Rate in the Young Sub-Neptune V1298 Tau c ------------------------------------------------------------------------------------ Type Cycle GO 34 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Guangwei Fu The Johns Hopkins University Y CoI: Prof. David K. Sing The Johns Hopkins University N CoI: Dr. Joshua D. Lothringer Space Telescope Science Institute N ------------------------------------------------------------------------------------ Abstract What shapes the exoplanet radius valley between super-Earths and sub-Neptunes: XUV-driven photoevaporation or core-powered mass loss? Direct mass-loss measurements during the first ~100 Myr when escape peaks are the key test. Current He I 1083 nm fits suffer an order-of-magnitude (T, Mdot) degeneracy; a multi-line hydrogen diagnostic breaks it. We propose 20 HST orbits (2 transits) of STIS G750M to detect H-alpha atmospheric escape from V1298 Tau c, a 23 Myr sub-Neptune (P=8.25 d, Rp~5.6 R_Earth, Mp~4.7 M_Earth) at the upper edge of the radius valley. The JWST NIRISS/SOSS transit already reveals a strong He I 1083 nm excess (~3400 ppm) and the first Paschen-alpha 1875 nm escape detection on any exoplanet (~2300 ppm), both with trailing tails >2 hr past egress. HST H-alpha completes the first simultaneous H-alpha + Pa-alpha + He I escape measurement on any exoplanet. The H-alpha/Pa-alpha depth ratio probes the n=2 and n=3 excited-hydrogen populations, providing a Balmer-Paschen thermometer that breaks the (T, Mdot) degeneracy. Combined with the JWST He I depth and non-LTE modeling framework, we will constrain the outflow temperature to ~5-10% and the mass-loss rate to better than 0.1 dex, an order-of-magnitude improvement over single-line analyses. Only HST/STIS delivers the ~15 hr continuous stare and few-hundred-ppm stability needed to resolve the post-egress tail; ground-based H-alpha and He I campaigns on V1298 Tau c have failed due to limited phase coverage. This measurement provides a critical calibration anchor for photoevaporation vs. core-powered mass-loss models and establishes a multi-line diagnostic framework for the growing sample of young transiting planets. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will observe two transits of the 23 Myr sub-Neptune V1298 Tau c with STIS/CCD G750M centered at 6581 A (covering H-alpha at 6563 A) through the 52X2 slit, to measure H-alpha absorption from the escaping atmosphere. Each visit is a single uninterrupted block of 10 orbits (~15 hr). Because the JWST NIRISS He I and Pa-alpha light curves show an asymmetric escape signature with a trailing tail extending more than 2 hr past egress, the transit is deliberately not centered in the visit: the phase constraint starts each visit 5.0-4.5 hr before mid-transit, giving ~2 orbits of pre-ingress baseline, the full 4.8 hr transit, the post-egress tail, and ~3 orbits of post-tail baseline to anchor the out-of-transit flux and recover the true transit depth. The phase constraint uses a JWST-anchored ephemeris (T0 = 2460924.7690 BJD_TDB from the 2025 Sep 6 NIRISS transit; P = 8.24924 d from the 2021 CHEOPS to 2025 JWST transit 18432( 2) - 30-Jul-2026 19:52:25 - [ 2] baseline). Each visit begins with a CCD target acquisition (F28X50LP), followed by time-series spectroscopy: 8 exposures of 238 s in orbit 1 and 10 per orbit thereafter (98 total per visit, ~260 s cadence). We acknowledge that these 10-orbit visits exceed 6 orbits and will execute under shared-risk long-stare scheduling in reduced gyro mode. ------------------------------------------------------------------------------------ 18432( 2) - 30-Jul-2026 19:52:25 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V-V1298-TAU STAR, K III-I RA=04H05M19.5910S, J2000 V = 10.12 DEC=+20D09'25.56" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 3.844113627474452E-4 -0.016052000023591972 0.0092577 ------------------------------------------------------------------------------------------------------------------------------------ 18432( 2) - 30-Jul-2026 19:52:25 - [ 4] Visit: 01 (V1298 Tau c H-alpha transit 1 of 2) Visit Requirements: Period 8.24924 D AND ZERO-PHASE HJD2460924.7690 On Hold Comments: Additional Comments: V1298 Tau c transit 1 of 2. 10 continuous orbits in a single visit (unbroken block). Phase constraint places visit start ~5.0-4.5 hr before predicted mid-transit: ~2 orbits pre-ingress baseline, full T14=4.67 hr transit, and post-egress coverage of the trailing tail plus ~2 orbits post-tail baseline. Shared-risk long-stare scheduling (>6 orbits) acknowledged in Phase I special requirements. 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 V-V1298-TAU STIS/CCD ACQ F28X50LP MIRROR 1 0.2 S (0.2 PHASE 0.974745148 TO S) 0.977270633 Comments: CCD target acquisition. Verify exposure time with STIS ETC for V=10.12 K1.5 star (scaled from heritage programs). ------------------------------------------------------------------------------------------------------------------------------------ 2 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 8 238 S SIZEAXIS2=128.0, WAVECAL=NO (1904 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 9 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 11 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 18432( 2) - 30-Jul-2026 19:52:25 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 12 WAVE STIS/CCD ACCUM 52X0.2 G750M 6581 1 DEF (0 S) Comments: Explicit WAVECAL; auto-wavecals disabled on science exposures. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-V1298-TAU 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 1 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 2 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 3 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 4 N/A 18432( 2) - 30-Jul-2026 19:52:25 - [ 6] 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 4 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 5 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 6 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 7 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 8 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 9 N/A 18432( 2) - 30-Jul-2026 19:52:25 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 9 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 10 N/A WAVE 12 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none none 10 N/A 18432( 2) - 30-Jul-2026 19:52:25 - [ 8] Visit: 02 (V1298 Tau c H-alpha transit 2 of 2) Visit Requirements: Period 8.24924 D AND ZERO-PHASE HJD2460924.7690 On Hold Comments: Additional Comments: V1298 Tau c transit 2 of 2. 10 continuous orbits in a single visit (unbroken block). Phase constraint places visit start ~5.0-4.5 hr before predicted mid-transit: ~2 orbits pre-ingress baseline, full T14=4.67 hr transit, and post-egress coverage of the trailing tail plus ~2 orbits post-tail baseline. Shared-risk long-stare scheduling (>6 orbits) acknowledged in Phase I special requirements. 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 V-V1298-TAU STIS/CCD ACQ F28X50LP MIRROR 1 0.2 S (0.2 PHASE 0.974745148 TO S) 0.977270633 Comments: CCD target acquisition. Verify exposure time with STIS ETC for V=10.12 K1.5 star (scaled from heritage programs). ------------------------------------------------------------------------------------------------------------------------------------ 2 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 8 238 S SIZEAXIS2=128.0, WAVECAL=NO (1904 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 9 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 11 V-V1298-TAU STIS/CCD ACCUM 52X2 G750M 6581 CR-SPLIT=NO, GAIN=4, 10 238 S SIZEAXIS2=128.0, WAVECAL=NO (2380 S) ------------------------------------------------------------------------------------------------------------------------------------ 18432( 2) - 30-Jul-2026 19:52:25 - [ 9] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 12 WAVE STIS/CCD ACCUM 52X0.2 G750M 6581 1 DEF (0 S) Comments: Explicit WAVECAL; auto-wavecals disabled on science exposures. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-V1298-TAU 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 1 N/A V-V1298-TAU 2 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 1 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 2 N/A V-V1298-TAU 3 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 2 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 3 N/A V-V1298-TAU 4 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 3 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 4 N/A 18432( 2) - 30-Jul-2026 19:52:25 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 4 N/A V-V1298-TAU 5 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 4 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 5 N/A V-V1298-TAU 6 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 5 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 6 N/A V-V1298-TAU 7 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 6 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 7 N/A V-V1298-TAU 8 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 7 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 8 N/A V-V1298-TAU 9 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 8 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 9 N/A 18432( 2) - 30-Jul-2026 19:52:25 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 9 N/A V-V1298-TAU 10 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 9 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 1 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 2 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 3 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 4 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 5 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 6 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 7 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 8 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 9 none 10 N/A V-V1298-TAU 11 STIS/CCD ACCUM 52X2 G750M 6581 none none 10 none 10 N/A WAVE 12 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none none 10 N/A 18432( 2) - 30-Jul-2026 19:52:25 - [ 12] Summary Form for Proposal 18432 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2, 52X2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO, GAIN=4, SIZEAXIS2=128.0, WAVECAL=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PHASE 0.974745148 TO 0.977270633, Period 8.24924 D AND ZERO-PHASE HJD2460924.7690 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G750M, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names V-V1298-TAU, WAVE ------------------------------------------------------------------------------------------------------------------------------------