18334( 4) - 28-Aug-2026 12:15:24 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18334 Version: 4 Check-in Time: 28-Aug-2026 12:15:24 STScI Edit Number: 0 Title Constraining the i-process with heavy-metal subdwarfs ------------------------------------------------------------------------------------ Type Cycle GO 34 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Matti Dorsch Universitat Potsdam Y CoI: Prof. C Simon Jeffery Armagh Observatory and Planetarium N CoI: Tiara Battich Max Planck Institute for Astrophysics N CoI: Stephan Geier Universitat Potsdam N CoI: Prof. Ulrich Heber Universitat Erlangen-Nurnberg N CoI: Dr. Evan Bauer Lawrence Livermore National Laboratory N CoI: Francisco Molina Universitat Potsdam N CoI: Dr. Maja Vuckovic Universidad de Valparaiso N CoI: Max Pritzkuleit Universitat Potsdam N ------------------------------------------------------------------------------------ Abstract The origin of heavy elements remains a fundamental problem in astrophysics, with growing evidence for an intermediate neutron-capture (i-)process beyond the classical s- and r-process framework. However, its astrophysical sites and yields remain poorly constrained due to degeneracies in evolved stars, where mixing, binary mass transfer, and ongoing nucleosynthesis obscure clear interpretation. Heavy-metal hot subdwarfs provide a uniquely clean environment to isolate the i-process. These core helium-burning stars bypass the asymptotic giant branch, excluding s-process enrichment on evolutionary grounds, and possess stable, radiative atmospheres free of deep convection. A subset of hot subdwarfs stars exhibits extreme overabundances of trans-iron elements, consistent with i-process nucleosynthesis triggered by proton ingestion during the helium core flash. Crucially, HST ultraviolet spectroscopy of the benchmark system EC22536-5304 enabled the first complete abundance pattern across the trans-iron regime, which is successfully reproduced by i-process models. We propose HST ultraviolet spectroscopy of 13 heavy-metal subdwarfs to obtain the first representative sample of complete trans-iron abundance patterns. The ultraviolet domain contains diagnostic lines of ~25 heavy elements inaccessible from the ground, enabling robust, quantitative comparisons with nucleosynthesis models. Our goals are (1) to definitively establish the i-process origin of the observed heavy-element enhancements through population-level abundance patterns, and (2) to constrain i-process yields as a function of metallicity and formation channel through direct comparison with state-of-the-art models. ------------------------------------------------------------------------------------ Observations Description ------------------------ Nine bright hot subdwarf stars (sdO/sdB) are observed with STIS/E140M (m_FUV < 13.2mag). Two of these stars can achieve SNR > 25 in a single orbit, seven require two orbits. 18334( 4) - 28-Aug-2026 12:15:24 - [ 2] The four fainter (14.6 < m_FUV < 15.4mag) stars are observed with COS/G130M-1291 and COS/G160M-1600 at one orbit per grating per target (two orbits each). Because the position of these stars is well known from Gaia DR3 and the COS aperature is large, we do not require a specific target acquisition for stars observed with COS. Three stars are binaries (sdOB + F5V main sequence star: PB-6355, PG1459-048, GALEX_J202216.8+015225). In each system, the sdOB completly dominates in the UV and the F-type takes over at wavlengths > 5000 Angstrom. Models used for the ETC consider both stars. The binaries are not resolved by HST. ------------------------------------------------------------------------------------ 18334( 4) - 28-Aug-2026 12:15:24 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HZ-44 STAR, SDB RA=13H23M35.2629S, J2000 V = 11.65 DEC=+36D07'59.54" Reference Frame: ICRS Extended: NO 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 -0.00544824618156454 -0.004407999904287863 0.0026703 ------------------------------------------------------------------------------------------------------------------------------------ 2 HE-2359-2844 STAR, SDB RA=00H01M38.4853S +/- 0.02e-3", J2000 V = 16.127 DEC=-28D27'43.03" +/- 0.02e-3" Reference Frame: ICRS Extended: NO 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 5.080758798644894E-4 -0.0069609999172826065 5.171E-4 ------------------------------------------------------------------------------------------------------------------------------------ 3 HE-1256-2738 STAR, SDB RA=12H59M1.3946S +/- 0.02e-3", J2000 V = 16.46 DEC=-27D54'18.77" +/- 0.02e-3" Reference Frame: ICRS Extended: NO 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 -0.0016100821118753678 -0.004898999964098039 4.566E-4 ------------------------------------------------------------------------------------------------------------------------------------ 18334( 4) - 28-Aug-2026 12:15:24 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 4 FEIGE-46 STAR, SDB RA=11H37M26.3701S, J2000 V = 13.24 DEC=+14D10'14.11" Reference Frame: ICRS Extended: NO 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 -0.005501332525855015 -0.045002000001659326 0.0020089 ------------------------------------------------------------------------------------------------------------------------------------ 5 PHL-417 STAR, SDB RA=23H11M5.1030S +/- 0.0563e-3", J2000 V = 17.1 DEC=-01D37'6.07" +/- 0.0606e-3" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2016 5.009331455462092E-4 -0.013321 0.3891e-3 ------------------------------------------------------------------------------------------------------------------------------------ 6 PG-1559+048 STAR, SDB RA=16H01M31.2726S, J2000 V = 14.46 DEC=+04D40'27.07" Reference Frame: ICRS Extended: NO 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 -8.882875984294333E-4 -9.92999935078842E-4 0.0013949000000000001 ------------------------------------------------------------------------------------------------------------------------------------ 18334( 4) - 28-Aug-2026 12:15:24 - [ 5] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 7 FBS-1749+373 STAR, SDB RA=17H51M37.3294S, J2000 V = 14.64 DEC=+37D19'51.12" Reference Frame: ICRS Extended: NO 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 -5.683645762255125E-4 0.001879 0.0012285999999999998 ------------------------------------------------------------------------------------------------------------------------------------ 8 CW83-0825+15 STAR, SDB RA=08H28M32.8677S, J2000 V = 11.82 DEC=+14D52'2.48" Reference Frame: ICRS Extended: NO 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 -0.0017995098947584567 -0.0018820000150299165 0.0037092 ------------------------------------------------------------------------------------------------------------------------------------ 9 GALEX-J00123 STAR, SDB RA=00H12M35.5690S +/- 0.02e-3", J2000 V = 16.202 5.6-422011 DEC=-42D20'11.70" +/- 0.02e-3" Reference Frame: ICRS Extended: NO 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 7.76062926416859E-4 -0.01586800005952682 4.4629999999999995E-4 ------------------------------------------------------------------------------------------------------------------------------------ 18334( 4) - 28-Aug-2026 12:15:24 - [ 6] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 10 FAUST-4434 STAR, SDB RA=19H12M23.6407S, J2000 V = 14.6 DEC=-62D46'32.76" Reference Frame: ICRS Extended: NO 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 -0.006079178848978868 -0.06930200004262588 8.681E-4 ------------------------------------------------------------------------------------------------------------------------------------ 11 PB-6355 STAR, SDB RA=01H16M27.3120S, J2000 V = 13.04 DEC=+06D03'11.61" Reference Frame: ICRS Extended: NO 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 -4.910713683375918E-4 -0.010783000016090227 0.0013049 ------------------------------------------------------------------------------------------------------------------------------------ 12 GALEX-J20221 STAR, SDB RA=20H22M16.7676S, J2000 V = 13.434 6.8+015225 DEC=+01D52'24.36" Reference Frame: ICRS Extended: NO 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 6.606864823112308E-4 -0.00356699993062648 0.0013875 ------------------------------------------------------------------------------------------------------------------------------------ 18334( 4) - 28-Aug-2026 12:15:24 - [ 7] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 13 PG-1459-048 STAR, SDB RA=15H02M6.4303S, J2000 V = 13.47 DEC=-04D59'38.14" Reference Frame: ICRS Extended: NO 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 -5.656137765590723E-4 -0.013199999966673204 0.001286 ------------------------------------------------------------------------------------------------------------------------------------ 18334( 4) - 28-Aug-2026 12:15:24 - [ 8] Visit: 01 Visit Requirements: On Hold Comments: 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 HZ-44 STIS/CCD ACQ F28X50LP MIRROR 1 0.5 S (0.5 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HZ-44 STIS/FUV ACCUM 0.2X0.2 E140M 1425 1 1800 S -MAMA see below (2185 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 | ------------------------------------------------------------------------------------------------------------------------------------ HZ-44 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A HZ-44 2 STIS/FUV ACCUM 0.2X0.2 E140M 1425 none none none none 1 2185.0 S -MAMA 18334( 4) - 28-Aug-2026 12:15:24 - [ 9] Visit: 02 Visit Requirements: On Hold Comments: 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 HE-2359-284 COS/NUV ACQ/IMA BOA MIRRORA 1 55 S (55 4 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HE-2359-284 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=570, FP-POS=3, 1 600 S 4 G LIFETIME-POS=LP7 see below (840 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HE-2359-284 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=570, FP-POS=4, 1 600 S 4 G LIFETIME-POS=LP7 see below (840 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HE-2359-284 COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=1950, FP-POS=ALL, 1 250 S 4 G LIFETIME-POS=LP10 see below (2128 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 | ------------------------------------------------------------------------------------------------------------------------------------ HE-2359-2844 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE HE-2359-2844 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 840.0 S G HE-2359-2844 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 840.0 S G HE-2359-2844 4 COS/FUV TIME-TA PSA G160M 1600 none none none 1 2 532.0 S G HE-2359-2844 4 COS/FUV TIME-TA PSA G160M 1600 none none none 2 2 532.0 S G HE-2359-2844 4 COS/FUV TIME-TA PSA G160M 1600 none none none 3 2 532.0 S G HE-2359-2844 4 COS/FUV TIME-TA PSA G160M 1600 none none none 4 2 532.0 S G 18334( 4) - 28-Aug-2026 12:15:24 - [ 10] Visit: 03 Visit Requirements: On Hold Comments: 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 HE-1256-273 COS/NUV ACQ/IMA BOA MIRRORA 1 90 S (90 8 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HE-1256-273 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1000, FP-POS=3, 1 600 S 8 G LIFETIME-POS=LP7 see below (790 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HE-1256-273 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1000, FP-POS=4, 1 600 S 8 G LIFETIME-POS=LP7 see below (790 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HE-1256-273 COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=3100, FP-POS=ALL, 1 250 S 8 G LIFETIME-POS=LP10 see below (2156 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 | ------------------------------------------------------------------------------------------------------------------------------------ HE-1256-2738 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE HE-1256-2738 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 790.0 S G HE-1256-2738 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 790.0 S G HE-1256-2738 4 COS/FUV TIME-TA PSA G160M 1600 none none none 1 2 539.0 S G HE-1256-2738 4 COS/FUV TIME-TA PSA G160M 1600 none none none 2 2 539.0 S G HE-1256-2738 4 COS/FUV TIME-TA PSA G160M 1600 none none none 3 2 539.0 S G HE-1256-2738 4 COS/FUV TIME-TA PSA G160M 1600 none none none 4 2 539.0 S G 18334( 4) - 28-Aug-2026 12:15:24 - [ 11] Visit: 04 Visit Requirements: On Hold Comments: 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 FEIGE-46 STIS/CCD ACQ F28X50LP MIRROR 1 1.2 S (1.2 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 FEIGE-46 STIS/FUV ACCUM 0.2X0.2 E140M 1425 1 1600 S -MAMA see below (2167 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 FEIGE-46 STIS/FUV ACCUM 0.2X0.2 E140M 1425 1 1800 S -MAMA see below (2564 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 FEIGE-46 STIS/FUV ACCUM 0.2X0.2 E140M 1425 1 1800 S -MAMA see below (2564 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 | ------------------------------------------------------------------------------------------------------------------------------------ FEIGE-46 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A FEIGE-46 2 STIS/FUV ACCUM 0.2X0.2 E140M 1425 none none none none 1 2167.0 S -MAMA FEIGE-46 3 STIS/FUV ACCUM 0.2X0.2 E140M 1425 none none none none 2 2564.0 S -MAMA FEIGE-46 4 STIS/FUV ACCUM 0.2X0.2 E140M 1425 none none none none 3 2564.0 S -MAMA 18334( 4) - 28-Aug-2026 12:15:24 - [ 12] Visit: 05 Visit Requirements: On Hold Comments: 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 PHL-417 COS/NUV ACQ/IMA BOA MIRRORA 1 98 S (98 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PHL-417 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1040, FP-POS=3, 1 600 S G LIFETIME-POS=LP7 see below (785 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PHL-417 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1040, FP-POS=4, 1 600 S G LIFETIME-POS=LP7 see below (785 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 PHL-417 COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=3400, FP-POS=ALL, 1 250 S G LIFETIME-POS=LP10 see below (2152 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 | ------------------------------------------------------------------------------------------------------------------------------------ PHL-417 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE PHL-417 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 785.0 S G PHL-417 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 785.0 S G PHL-417 4 COS/FUV TIME-TA PSA G160M 1600 none none none 1 2 538.0 S G PHL-417 4 COS/FUV TIME-TA PSA G160M 1600 none none none 2 2 538.0 S G PHL-417 4 COS/FUV TIME-TA PSA G160M 1600 none none none 3 2 538.0 S G PHL-417 4 COS/FUV TIME-TA PSA G160M 1600 none none none 4 2 538.0 S G 18334( 4) - 28-Aug-2026 12:15:24 - [ 13] Visit: 06 Visit Requirements: On Hold Comments: 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 PG-1559+048 STIS/CCD ACQ F28X50LP MIRROR 1 3.6 S (3.6 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PG-1559+048 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=790 1 1700 S -MAMA G see below (2104 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PG-1559+048 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=790 1 1700 S -MAMA G see below (2569 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 PG-1559+048 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=790 1 1700 S -MAMA G see below (2569 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 | ------------------------------------------------------------------------------------------------------------------------------------ PG-1559+048 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A PG-1559+048 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 2104.0 S -MAMA G PG-1559+048 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 2569.0 S -MAMA G PG-1559+048 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 2569.0 S -MAMA G 18334( 4) - 28-Aug-2026 12:15:24 - [ 14] Visit: 07 Visit Requirements: On Hold Comments: 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 FBS-1749+37 STIS/CCD ACQ F28X50LP MIRROR 1 4.0 S (4 3 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 FBS-1749+37 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=640 1 1700 S 3 -MAMA G see below (2115 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 FBS-1749+37 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=640 1 1700 S 3 -MAMA G see below (2582 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 FBS-1749+37 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=640 1 1700 S 3 -MAMA G see below (2582 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 | ------------------------------------------------------------------------------------------------------------------------------------ FBS-1749+373 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A FBS-1749+373 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 2115.0 S -MAMA G FBS-1749+373 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 2582.0 S -MAMA G FBS-1749+373 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 2582.0 S -MAMA G 18334( 4) - 28-Aug-2026 12:15:24 - [ 15] Visit: 08 Visit Requirements: On Hold Comments: 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 CW83-0825+1 STIS/CCD ACQ F28X50LP MIRROR 1 0.5 S (0.5 5 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 CW83-0825+1 STIS/FUV ACCUM 0.2X0.2 E140M 1425 1 1900 S 5 -MAMA see below (2167 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 | ------------------------------------------------------------------------------------------------------------------------------------ CW83-0825+15 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A CW83-0825+15 2 STIS/FUV ACCUM 0.2X0.2 E140M 1425 none none none none 1 2167.0 S -MAMA 18334( 4) - 28-Aug-2026 12:15:24 - [ 16] Visit: 09 Visit Requirements: On Hold Comments: 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 GALEX-J0012 COS/NUV ACQ/IMA BOA MIRRORA 1 70 S (70 35.6-422011 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 GALEX-J0012 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=530, FP-POS=3, 1 600 S 35.6-422011 G LIFETIME-POS=LP7 see below (818 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 GALEX-J0012 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=530, FP-POS=4, 1 600 S 35.6-422011 G LIFETIME-POS=LP7 see below (818 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 GALEX-J0012 COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=1840, FP-POS=ALL, 1 290 S 35.6-422011 G LIFETIME-POS=LP10 see below (2176 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 | ------------------------------------------------------------------------------------------------------------------------------------ GALEX-J001235.6-422 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A 011 GE GALEX-J001235.6-422 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 818.0 S 011 G GALEX-J001235.6-422 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 818.0 S 011 G GALEX-J001235.6-422 4 COS/FUV TIME-TA PSA G160M 1600 none none none 1 2 544.0 S 011 G GALEX-J001235.6-422 4 COS/FUV TIME-TA PSA G160M 1600 none none none 2 2 544.0 S 011 G GALEX-J001235.6-422 4 COS/FUV TIME-TA PSA G160M 1600 none none none 3 2 544.0 S 011 G GALEX-J001235.6-422 4 COS/FUV TIME-TA PSA G160M 1600 none none none 4 2 544.0 S 011 G 18334( 4) - 28-Aug-2026 12:15:24 - [ 17] Visit: 10 Visit Requirements: On Hold Comments: 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 FAUST-4434 STIS/CCD ACQ F28X50LP MIRROR 1 4 S (4 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 FAUST-4434 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=740 1 1700 S -MAMA G see below (2187 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 FAUST-4434 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=740 1 1700 S -MAMA G see below (2654 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 FAUST-4434 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=740 1 1700 S -MAMA G see below (2654 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 | ------------------------------------------------------------------------------------------------------------------------------------ FAUST-4434 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A FAUST-4434 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 2187.0 S -MAMA G FAUST-4434 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 2654.0 S -MAMA G FAUST-4434 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 2654.0 S -MAMA G 18334( 4) - 28-Aug-2026 12:15:24 - [ 18] Visit: 11 Visit Requirements: On Hold Comments: 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 PB-6355 STIS/CCD ACQ F28X50LP MIRROR 1 0.6 S (0.6 S) Comments: Binary star, not resolved by HST; considered in all ETC runs ------------------------------------------------------------------------------------------------------------------------------------ 2 PB-6355 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=600 1 1700 S -MAMA G see below (2114 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PB-6355 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=600 1 1700 S -MAMA G see below (2567 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 PB-6355 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=600 1 1700 S -MAMA G see below (2567 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 | ------------------------------------------------------------------------------------------------------------------------------------ PB-6355 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A PB-6355 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 2114.0 S -MAMA G PB-6355 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 2567.0 S -MAMA G PB-6355 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 2567.0 S -MAMA G 18334( 4) - 28-Aug-2026 12:15:24 - [ 19] Visit: 12 Visit Requirements: On Hold Comments: 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 GALEX-J2022 STIS/CCD ACQ F28X50LP MIRROR 1 0.7 S (0.7 16.8+015225 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 GALEX-J2022 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=760 1 1700 S 16.8+015225 -MAMA G see below (2116 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 GALEX-J2022 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=760 1 1700 S 16.8+015225 -MAMA G see below (2569 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 GALEX-J2022 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=760 1 1700 S 16.8+015225 -MAMA G see below (2569 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 | ------------------------------------------------------------------------------------------------------------------------------------ GALEX-J202216.8+015 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A 225 GALEX-J202216.8+015 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 2116.0 S 225 -MAMA G GALEX-J202216.8+015 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 2569.0 S 225 -MAMA G GALEX-J202216.8+015 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 2569.0 S 225 -MAMA G 18334( 4) - 28-Aug-2026 12:15:24 - [ 20] Visit: 13 Visit Requirements: On Hold Comments: 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 PG-1459-048 STIS/CCD ACQ F28X50LP MIRROR 1 1 S (1 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PG-1459-048 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=720 1 1700 S -MAMA G see below (2114 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PG-1459-048 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=720 1 1700 S -MAMA G see below (2569 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 PG-1459-048 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=720 1 1700 S -MAMA G see below (2569 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 | ------------------------------------------------------------------------------------------------------------------------------------ PG-1459-048 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A PG-1459-048 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 2114.0 S -MAMA G PG-1459-048 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 2569.0 S -MAMA G PG-1459-048 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 2569.0 S -MAMA G 18334( 4) - 28-Aug-2026 12:15:24 - [ 21] Summary Form for Proposal 18334 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.2X0.2, BOA, F28X50LP, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV, STIS/CCD, STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1000, BUFFER-TIME=1040, BUFFER-TIME=1840, BUFFER-TIME=1950, BUFFER-TIME=3100, BUFFER-TIME=3400, BUFFER-TIME=530, BUFFER-TIME=570, BUFFER-TIME=600, BUFFER-TIME=640, BUFFER-TIME=720, BUFFER-TIME=740, BUFFER-TIME=760, BUFFER-TIME=790, FP-POS=3, FP-POS=4, FP-POS=ALL, LIFETIME-POS=LP10, LIFETIME-POS=LP7 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements E140M, G130M, G160M, MIRROR, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names CW83-0825+15, FAUST-4434, FBS-1749+373, FEIGE-46, GALEX-J001235.6-422011, GALEX-J202216.8+015225, HE-1256-2738, HE-2359-2844, HZ-44, PB-6355, PG-1459-048, PG-1559+048, PHL-417 ------------------------------------------------------------------------------------------------------------------------------------