18399( 2) - 31-Jul-2026 22:27:06 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18399 Version: 2 Check-in Time: 31-Jul-2026 22:27:06 STScI Edit Number: 0 Title Characterisation of exocomets in the 49 Cet system ------------------------------------------------------------------------------------ Type Cycle GO 34 ------------------------------------------------------------------------------------ Investigators Contact? PI: Mr. Theo Vrignaud CNRS, Institut d'Astrophysique de Paris Y CoI: Dr. Alain Lecavelier des Etangs CNRS, Institut d'Astrophysique de Paris Y CoI: Dr. Guillaume Hebrard CNRS, Institut d'Astrophysique de Paris N CoI: Dr. Alfred Vidal-Madjar CNRS, Institut d'Astrophysique de Paris N CoI: Dr. Flavien Kiefer Observatoire de Paris - Section de Meudon N CoI: Dr. Aline Novais Lund University N CoI: Dr. Jens Hoeijmakers Lund University N CoI: Klaudia Jaworska Lund University N ------------------------------------------------------------------------------------ Abstract 49 Ceti is a young (40 Myr) A1V star hosting a prominent debris disc and standing as one of only three systems where spectroscopic signatures of transiting exocomets have been confirmed. Previous HST observations revealed strong exocomet absorption in carbon lines (C II, C IV), but the absence of simultaneous coverage of refractory species (Mg II, Fe II) prevented any measurement of the volatile-to-refractory content of these objects, leaving their composition and formation history unconstrained. We propose to obtain high-resolution UV spectra of 49 Cet at five distinct epochs with HST/STIS, covering the full 1250-2900 A range at resolving power > 100, 000. Each visit consists of 3 sequential orbits using the E140H and E230H gratings, providing simultaneous access to volatile tracers (C I, C II, C IV, O I) and refractory species (such as Fe II and Mg II). These observations will allow us to: (1) characterise the physical properties of 49 Cet exocomets (dynamics, distance to the star, ionisation state) and assess how these properties are shaped by the high stellar luminosity; (2) measure their elemental C/Fe ratios, which will yield valuable insight into their formation location and nature; and (3) test whether exocomet evaporation can explain the replenishment of the observed carbon-rich gaseous disc. This programme will deliver a complete characterisation of exocomets in the 49 Ceti system, opening a new window into the properties of small bodies across the diversity of extrasolar systems and how they can contribute to redistribute volatiles throughout planetary systems. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of HST program 18399 is to determine the physical and chemical properties of exocomets in the 49 Cet system. The observing strategy consists of obtaining 5 high-resolution spectra of 49 Cet at different epochs, each separated by at least 10 days. At each epoch, we expect to detect a small number of exocomet gas tails transiting the star, 18399( 2) - 31-Jul-2026 22:27:06 - [ 2] typically 0-3. The absorption signatures of these exocomets will be observed in numerous atomic species, including carbon, oxygen, iron, and magnesium. These observations will provide constraints on the bulk composition of exocomets in the 49 Cet system, as well as on the physical processes governing exocomet evolution around hot stars (Teff = 9000 K). Each visit will consist of 3 consecutive HST orbits using the STIS instrument. To cover the full 1280-2900 wavelength range, the exposures are distributed as follows: - Orbit 1: A single exposure with the FUV/MAMA/E140H grating at the i1380 central wavelength, covering lines of C I, C II, O I, and Si IV. A long exposure time (Texp = 1900s) is required to compensate for the low stellar flux at these wavelengths. This observation is divided into 5 sub-exposures, allowing us to monitor the temporal evolution of the detected exocomet signatures. - Orbit 2: Two exposures: - FUV/MAMA/E140H at the c1598 central wavelength (Texp = 1600s, divided into 4 sub-exposures), covering Si II, C I, IV, and Al II. - NUV/MAMA/E230H at the c1763 central wavelength (Texp = 600s), covering Fe II and Al III. - Orbit 3: Four exposures (Texp = 420s each), all with the NUV/MAMA/E230H grating: - c2013, covering C I, Cr II, and Zn II. - c2263, covering Ni II and Fe II. - c2513, covering Fe I and Fe II. - c2763, covering Fe II, Mg I, and Mg II. The E140H and E230H gratings provide a resolving power > 100, 000, enabling the absorption signatures of individual transiting exocomets to be resolved in great detail. All observations will be obtained through the 0.2"x0.2" aperture. The maximum count rates predicted by the ETC are approximately 100, 000 cts/s, well below the STIS brightness limit for non-variable targets. The expected S/N per resolution element ranges from 40 to 60 across the observed spectral range. ------------------------------------------------------------------------------------ 18399( 2) - 31-Jul-2026 22:27:06 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 49-CET STAR, A0-A3 V-IV RA=01H34M37.7786S +/- J2000 V = 5.607 0.0339E-3", DEC=-15D40'34.90" +/- 0.0242" Reference Frame: ICRS Extended: NO Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.006533075463417794 -0.00313 0.0174725 ------------------------------------------------------------------------------------------------------------------------------------ 18399( 2) - 31-Jul-2026 22:27:06 - [ 4] 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 49-CET STIS/CCD ACQ F25ND3 MIRROR 1 0.2 S (0.2 SEQ 1-3 NON-INT S) ------------------------------------------------------------------------------------------------------------------------------------ 2 49-CET STIS/FUV ACCUM 0.2X0.2 E140H 1380 WAVECAL=NO 5 400 S -MAMA see below (1925 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/FUV ACCUM 0.2X0.2 E140H 1380 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE STIS/FUV ACCUM 0.2X0.2 E140H 1598 1 DEF (0 S) SEQ 4-7 NON-INT -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 5 49-CET STIS/FUV ACCUM 0.2X0.2 E140H 1598 WAVECAL=NO 4 400 S -MAMA see below (1596 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 1763 WAVECAL=NO 1 600 S -MAMA see below (599 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 1763 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 8 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2263 1 DEF (0 S) SEQ 8-15 NON-INT -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 9 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2263 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 10 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2263 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 11 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2263 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 12 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2513 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 13 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2513 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 18399( 2) - 31-Jul-2026 22:27:06 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 14 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2762 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 15 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2762 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 49-CET 1 STIS/CCD ACQ F25ND3 MIRROR none none none none 1 N/A 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 1 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 2 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 3 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 4 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 5 none 1 385.0 S -MAMA WAVE 3 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none none none 1 N/A -MAMA WAVE 4 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none none none 2 N/A -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 1 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 2 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 3 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 4 none 2 399.0 S -MAMA 49-CET 6 STIS/NUV ACCUM 0.2X0.2 E230H 1763 none none none none 2 599.0 S -MAMA WAVE 7 STIS/NUV ACCUM 0.2X0.2 E230H 1763 none none none none 2 N/A -MAMA WAVE 8 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 49-CET 9 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 49-CET 10 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA WAVE 11 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 18399( 2) - 31-Jul-2026 22:27:06 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 49-CET 12 STIS/NUV ACCUM 0.2X0.2 E230H 2513 none none none none 3 N/A -MAMA WAVE 13 STIS/NUV ACCUM 0.2X0.2 E230H 2513 none none none none 3 N/A -MAMA 49-CET 14 STIS/NUV ACCUM 0.2X0.2 E230H 2762 none none none none 3 N/A -MAMA WAVE 15 STIS/NUV ACCUM 0.2X0.2 E230H 2762 none none none none 3 N/A -MAMA 18399( 2) - 31-Jul-2026 22:27:06 - [ 7] Visit: 02 Visit Requirements: AFTER 01 BY 10 D TO 500 D 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 49-CET STIS/CCD ACQ F25ND3 MIRROR 1 0.2 S (0.2 SEQ 1-3 NON-INT S) ------------------------------------------------------------------------------------------------------------------------------------ 2 49-CET STIS/FUV ACCUM 0.2X0.2 E140H 1380 WAVECAL=NO 5 400 S -MAMA see below (1925 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/FUV ACCUM 0.2X0.2 E140H 1380 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE STIS/FUV ACCUM 0.2X0.2 E140H 1598 1 DEF (0 S) SEQ 4-7 NON-INT -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 5 49-CET STIS/FUV ACCUM 0.2X0.2 E140H 1598 WAVECAL=NO 4 400 S -MAMA see below (1596 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 1763 WAVECAL=NO 1 600 S -MAMA see below (599 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 1763 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 8 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2263 1 DEF (0 S) SEQ 8-15 NON-INT -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 9 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2263 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 10 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2263 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 11 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2263 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 12 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2513 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 13 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2513 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 18399( 2) - 31-Jul-2026 22:27:06 - [ 8] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 14 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2762 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 15 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2762 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 49-CET 1 STIS/CCD ACQ F25ND3 MIRROR none none none none 1 N/A 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 1 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 2 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 3 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 4 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 5 none 1 385.0 S -MAMA WAVE 3 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none none none 1 N/A -MAMA WAVE 4 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none none none 2 N/A -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 1 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 2 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 3 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 4 none 2 399.0 S -MAMA 49-CET 6 STIS/NUV ACCUM 0.2X0.2 E230H 1763 none none none none 2 599.0 S -MAMA WAVE 7 STIS/NUV ACCUM 0.2X0.2 E230H 1763 none none none none 2 N/A -MAMA WAVE 8 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 49-CET 9 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 49-CET 10 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA WAVE 11 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 18399( 2) - 31-Jul-2026 22:27:06 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 49-CET 12 STIS/NUV ACCUM 0.2X0.2 E230H 2513 none none none none 3 N/A -MAMA WAVE 13 STIS/NUV ACCUM 0.2X0.2 E230H 2513 none none none none 3 N/A -MAMA 49-CET 14 STIS/NUV ACCUM 0.2X0.2 E230H 2762 none none none none 3 N/A -MAMA WAVE 15 STIS/NUV ACCUM 0.2X0.2 E230H 2762 none none none none 3 N/A -MAMA 18399( 2) - 31-Jul-2026 22:27:06 - [ 10] Visit: 03 Visit Requirements: AFTER 02 BY 10 D TO 500 D 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 49-CET STIS/CCD ACQ F25ND3 MIRROR 1 0.2 S (0.2 SEQ 1-3 NON-INT S) ------------------------------------------------------------------------------------------------------------------------------------ 2 49-CET STIS/FUV ACCUM 0.2X0.2 E140H 1380 WAVECAL=NO 5 400 S -MAMA see below (1925 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/FUV ACCUM 0.2X0.2 E140H 1380 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE STIS/FUV ACCUM 0.2X0.2 E140H 1598 1 DEF (0 S) SEQ 4-7 NON-INT -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 5 49-CET STIS/FUV ACCUM 0.2X0.2 E140H 1598 WAVECAL=NO 4 400 S -MAMA see below (1596 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 1763 WAVECAL=NO 1 600 S -MAMA see below (599 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 1763 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 8 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2263 1 DEF (0 S) SEQ 8-15 NON-INT -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 9 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2263 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 10 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2263 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 11 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2263 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 12 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2513 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 13 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2513 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 18399( 2) - 31-Jul-2026 22:27:06 - [ 11] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 14 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2762 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 15 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2762 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 49-CET 1 STIS/CCD ACQ F25ND3 MIRROR none none none none 1 N/A 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 1 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 2 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 3 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 4 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 5 none 1 385.0 S -MAMA WAVE 3 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none none none 1 N/A -MAMA WAVE 4 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none none none 2 N/A -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 1 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 2 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 3 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 4 none 2 399.0 S -MAMA 49-CET 6 STIS/NUV ACCUM 0.2X0.2 E230H 1763 none none none none 2 599.0 S -MAMA WAVE 7 STIS/NUV ACCUM 0.2X0.2 E230H 1763 none none none none 2 N/A -MAMA WAVE 8 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 49-CET 9 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 49-CET 10 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA WAVE 11 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 18399( 2) - 31-Jul-2026 22:27:06 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 49-CET 12 STIS/NUV ACCUM 0.2X0.2 E230H 2513 none none none none 3 N/A -MAMA WAVE 13 STIS/NUV ACCUM 0.2X0.2 E230H 2513 none none none none 3 N/A -MAMA 49-CET 14 STIS/NUV ACCUM 0.2X0.2 E230H 2762 none none none none 3 N/A -MAMA WAVE 15 STIS/NUV ACCUM 0.2X0.2 E230H 2762 none none none none 3 N/A -MAMA 18399( 2) - 31-Jul-2026 22:27:06 - [ 13] Visit: 04 Visit Requirements: AFTER 03 BY 10 D TO 500 D 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 49-CET STIS/CCD ACQ F25ND3 MIRROR 1 0.2 S (0.2 SEQ 1-3 NON-INT S) ------------------------------------------------------------------------------------------------------------------------------------ 2 49-CET STIS/FUV ACCUM 0.2X0.2 E140H 1380 WAVECAL=NO 5 400 S -MAMA see below (1925 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/FUV ACCUM 0.2X0.2 E140H 1380 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE STIS/FUV ACCUM 0.2X0.2 E140H 1598 1 DEF (0 S) SEQ 4-7 NON-INT -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 5 49-CET STIS/FUV ACCUM 0.2X0.2 E140H 1598 WAVECAL=NO 4 400 S -MAMA see below (1596 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 1763 WAVECAL=NO 1 600 S -MAMA see below (599 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 1763 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 8 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2263 1 DEF (0 S) SEQ 8-15 NON-INT -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 9 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2263 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 10 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2263 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 11 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2263 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 12 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2513 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 13 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2513 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 18399( 2) - 31-Jul-2026 22:27:06 - [ 14] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 14 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2762 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 15 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2762 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 49-CET 1 STIS/CCD ACQ F25ND3 MIRROR none none none none 1 N/A 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 1 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 2 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 3 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 4 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 5 none 1 385.0 S -MAMA WAVE 3 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none none none 1 N/A -MAMA WAVE 4 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none none none 2 N/A -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 1 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 2 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 3 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 4 none 2 399.0 S -MAMA 49-CET 6 STIS/NUV ACCUM 0.2X0.2 E230H 1763 none none none none 2 599.0 S -MAMA WAVE 7 STIS/NUV ACCUM 0.2X0.2 E230H 1763 none none none none 2 N/A -MAMA WAVE 8 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 49-CET 9 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 49-CET 10 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA WAVE 11 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 18399( 2) - 31-Jul-2026 22:27:06 - [ 15] 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 | ------------------------------------------------------------------------------------------------------------------------------------ 49-CET 12 STIS/NUV ACCUM 0.2X0.2 E230H 2513 none none none none 3 N/A -MAMA WAVE 13 STIS/NUV ACCUM 0.2X0.2 E230H 2513 none none none none 3 N/A -MAMA 49-CET 14 STIS/NUV ACCUM 0.2X0.2 E230H 2762 none none none none 3 N/A -MAMA WAVE 15 STIS/NUV ACCUM 0.2X0.2 E230H 2762 none none none none 3 N/A -MAMA 18399( 2) - 31-Jul-2026 22:27:06 - [ 16] Visit: 05 Visit Requirements: AFTER 04 BY 10 D TO 500 D 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 49-CET STIS/CCD ACQ F25ND3 MIRROR 1 0.2 S (0.2 SEQ 1-3 NON-INT S) ------------------------------------------------------------------------------------------------------------------------------------ 2 49-CET STIS/FUV ACCUM 0.2X0.2 E140H 1380 WAVECAL=NO 5 400 S -MAMA see below (1925 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/FUV ACCUM 0.2X0.2 E140H 1380 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE STIS/FUV ACCUM 0.2X0.2 E140H 1598 1 DEF (0 S) SEQ 4-7 NON-INT -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 5 49-CET STIS/FUV ACCUM 0.2X0.2 E140H 1598 WAVECAL=NO 4 400 S -MAMA see below (1596 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 1763 WAVECAL=NO 1 600 S -MAMA see below (599 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 1763 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 8 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2263 1 DEF (0 S) SEQ 8-15 NON-INT -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 9 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2263 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 10 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2263 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 11 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2263 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 12 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2513 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 13 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2513 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 18399( 2) - 31-Jul-2026 22:27:06 - [ 17] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 14 49-CET STIS/NUV ACCUM 0.2X0.2 E230H 2762 WAVECAL=NO 1 420 S (420 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 15 WAVE STIS/NUV ACCUM 0.2X0.2 E230H 2762 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 49-CET 1 STIS/CCD ACQ F25ND3 MIRROR none none none none 1 N/A 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 1 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 2 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 3 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 4 none 1 385.0 S -MAMA 49-CET 2 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none 5 none 1 385.0 S -MAMA WAVE 3 STIS/FUV ACCUM 0.2X0.2 E140H 1380 none none none none 1 N/A -MAMA WAVE 4 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none none none 2 N/A -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 1 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 2 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 3 none 2 399.0 S -MAMA 49-CET 5 STIS/FUV ACCUM 0.2X0.2 E140H 1598 none none 4 none 2 399.0 S -MAMA 49-CET 6 STIS/NUV ACCUM 0.2X0.2 E230H 1763 none none none none 2 599.0 S -MAMA WAVE 7 STIS/NUV ACCUM 0.2X0.2 E230H 1763 none none none none 2 N/A -MAMA WAVE 8 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 49-CET 9 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 49-CET 10 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA WAVE 11 STIS/NUV ACCUM 0.2X0.2 E230H 2263 none none none none 3 N/A -MAMA 18399( 2) - 31-Jul-2026 22:27:06 - [ 18] 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 | ------------------------------------------------------------------------------------------------------------------------------------ 49-CET 12 STIS/NUV ACCUM 0.2X0.2 E230H 2513 none none none none 3 N/A -MAMA WAVE 13 STIS/NUV ACCUM 0.2X0.2 E230H 2513 none none none none 3 N/A -MAMA 49-CET 14 STIS/NUV ACCUM 0.2X0.2 E230H 2762 none none none none 3 N/A -MAMA WAVE 15 STIS/NUV ACCUM 0.2X0.2 E230H 2762 none none none none 3 N/A -MAMA 18399( 2) - 31-Jul-2026 22:27:06 - [ 19] Summary Form for Proposal 18399 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.2X0.2, F25ND3 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters WAVECAL=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 10 D TO 500 D, AFTER 02 BY 10 D TO 500 D, AFTER 03 BY 10 D TO 500 D, AFTER 04 BY 10 D TO 500 D, SEQ 1-3 NON-INT, SEQ 4-7 NON-INT, SEQ 8-15 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements E140H, E230H, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names 49-CET, WAVE ------------------------------------------------------------------------------------------------------------------------------------