18356( 2) - 17-Aug-2026 15:05:29 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18356 Version: 2 Check-in Time: 17-Aug-2026 15:05:29 STScI Edit Number: 0 Title Extreme Mass Transfer and Mass Loss in the Massive Interacting Binary W Serpentis ------------------------------------------------------------------------------------ Type Cycle GO 34 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Douglas Russell Gies Georgia State University Research Y Foundation CoI: Katherine Shepard Georgia State University Research N Foundation ------------------------------------------------------------------------------------ Abstract W Ser is the proto-type of a rare type of interacting massive binary that is experiencing a stage of very high mass transfer rate. The donor will be stripped of its envelope, while the gainer will emerge as a massive rapid rotator. The evolutionary destiny is set by how much of the mass transfer is captured by the gainer or lost from the binary. W Ser is surrounded by a dense circumbinary disk that indicates that systemic mass loss is underway. The donor star is cool, so the flux in the ultraviolet spectrum originates in gas in the vicinity of the gainer star. HST/COS spectra obtained around the orbit will show where and how the high excitation emission lines are formed through accretion power. These observations will demonstrate the importance of systemic mass loss for massive binaries and their remnants. ------------------------------------------------------------------------------------ Observations Description ------------------------ The binary consists of a cool mass donor and a hot mass gainer embedded in an accretion disk. The accretion disk flux will dominate in the FUV, and in this program we record the orbital phase variations in the FUV continuum and emission lines to map out the flux components from the accretion stream, occulting disk, and outflow into a circumbinary disk. The COS G160M grating is ideal for the required spectral resolution to measure Doppler shifts of several key emission lines including Si IV 1400, C IV 1550, and O III 1666. We plan to obtain FUV spectra using three central wavelengths (1533, 1577, and 1600 Angstroms) to cover the gaps between the A and B segments of COS. The spectra will made with all four FP-POS offset positions in each case to optimize the S/N ratio. Based upon ETC calculations, we expect to obtain a net S/N = 10 in the continuum and 35 at the peak of the strongest emission line per visit. There will be six visits to sample the full range of orbital phase with one of these centered on the eclipse of the disk by the mass donor star to determine the spatial extent of the eclipsed flux. The total counts at the brightest pixel summmed over six visits is about 60 counts, so the observations meet the safety requirements of COS. ------------------------------------------------------------------------------------ 18356( 2) - 17-Aug-2026 15:05:29 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V-W-SER STAR, ALGOL SYSTEM, RA=18H09M50.6486S +/- 0.021", J2000 V = -27 V = 8.42 +/- 1.0 F(1500) = 1.4E-13 CIRCUMSTELLAR MATTER, DEC=-15D33'0.26" +/- 0.017" erg/s/cm^2/Angstrom EMISSION LINE STAR, SHELL STAR 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. The ETC calculations were made using IUE low dispersion spectra as the source for flux. There are three bright emission lines in the range 1342 to 1774 Angstroms: Si IV 1400 C IV 1550 O III 1666 The peak intensities are reduced in the low dispersion IUE spectra, but there are two HST/GHRS spectra in the archive with comparable spectral resolution to COS. These record the Si IV doublet that is narrower but fully resolved and appears with a peak flux that is 4.36 times larger (peak to continuum) than that of the low resolution IUE spectrum. The other two lines are formed in similar environments in the binary system, so they should also be fully resolved at the COS spectral resolution. Consequently, we multiplied the IUE fluxes of these three emission lines by the same factor of 4.36 to estimate the peak emission line fluxes. This will lead to a small over-estimate of the total wavelength-integrated counts in the ETC, but the emission line peak counts should be consistent with the expectations from the archival HST/GHRS spectra of the target. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 4.082777106245477E-5 0.003058 0.001134 ------------------------------------------------------------------------------------------------------------------------------------ 18356( 2) - 17-Aug-2026 15:05:29 - [ 3] Visit: 01 (V1) Visit Requirements: Period 14.18608 D AND ZERO-PHASE HJD2461775.1589 On Hold Comments: Additional Comments: Visit 1 corresponds to an eclipse phase. Primary minimum occurs at HJD 2461775.8089 or phaseIngress)=0.046. Epoch used for APT is T(min)-0.65 days, so that this eclipse visit occurs between phase 0.0 and 0.092. 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-W-SER COS/NUV ACQ/IMA BOA MIRRORA 1 3.5 S (3.5 PHASE 0.00 TO 0.0916 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 V-W-SER COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, LIFETIME-POS=LP10, 1 36. S G BUFFER-TIME=380 see below (248 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 V-W-SER COS/FUV TIME-TA PSA G160M 1577 FP-POS=ALL, LIFETIME-POS=LP10, 1 35. S G BUFFER-TIME=346 see below (244 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 V-W-SER COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=500, FP-POS=ALL, 1 46. S G LIFETIME-POS=LP10 see below (288 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-W-SER 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 1 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 2 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 3 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 4 1 62.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 1 61.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 4] 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-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 1 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 2 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 3 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 4 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 5] Visit: 02 (V2) Visit Requirements: Period 14.18608 D AND ZERO-PHASE HJD2461775.1589 On Hold Comments: Additional Comments: Visit 2 for phase 0.095 to 0.270. 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-W-SER COS/NUV ACQ/IMA BOA MIRRORA 1 3.5 S (3.5 PHASE 0.095 TO 0.270 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 V-W-SER COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, LIFETIME-POS=LP10, 1 36. S G BUFFER-TIME=380 see below (248 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 V-W-SER COS/FUV TIME-TA PSA G160M 1577 FP-POS=ALL, LIFETIME-POS=LP10, 1 35. S G BUFFER-TIME=346 see below (244 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 V-W-SER COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=500, FP-POS=ALL, 1 46. S G LIFETIME-POS=LP10 see below (288 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-W-SER 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 1 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 2 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 3 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 4 1 62.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 1 61.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 1 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 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-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 2 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 3 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 4 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 7] Visit: 03 (V3) Visit Requirements: Period 14.18608 D AND ZERO-PHASE HJD2461775.1589 On Hold Comments: Additional Comments: Visit 3 for phase 0.276 to 0.452. 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-W-SER COS/NUV ACQ/IMA BOA MIRRORA 1 3.5 S (3.5 PHASE 0.276 TO 0.452 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 V-W-SER COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, LIFETIME-POS=LP10, 1 36. S G BUFFER-TIME=380 see below (248 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 V-W-SER COS/FUV TIME-TA PSA G160M 1577 FP-POS=ALL, LIFETIME-POS=LP10, 1 35. S G BUFFER-TIME=346 see below (244 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 V-W-SER COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=500, FP-POS=ALL, 1 46. S G LIFETIME-POS=LP10 see below (288 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-W-SER 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 1 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 2 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 3 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 4 1 62.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 1 61.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 1 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 8] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 2 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 3 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 4 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 9] Visit: 04 (V4) Visit Requirements: Period 14.18608 D AND ZERO-PHASE HJD2461775.1589 On Hold Comments: Additional Comments: Visit 4 for phase 0.458 to 0.634. 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-W-SER COS/NUV ACQ/IMA BOA MIRRORA 1 3.5 S (3.5 PHASE 0.458 TO 0.634 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 V-W-SER COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, LIFETIME-POS=LP10, 1 36. S G BUFFER-TIME=380 see below (248 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 V-W-SER COS/FUV TIME-TA PSA G160M 1577 FP-POS=ALL, LIFETIME-POS=LP10, 1 35. S G BUFFER-TIME=346 see below (244 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 V-W-SER COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=500, FP-POS=ALL, 1 46. S G LIFETIME-POS=LP10 see below (288 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-W-SER 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 1 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 2 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 3 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 4 1 62.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 1 61.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 1 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 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-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 2 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 3 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 4 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 11] Visit: 05 (V5) Visit Requirements: Period 14.18608 D AND ZERO-PHASE HJD2461775.1589 On Hold Comments: Additional Comments: Visit 5 for phase 0.640 to 0.815. 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-W-SER COS/NUV ACQ/IMA BOA MIRRORA 1 3.5 S (3.5 PHASE 0.640 TO 0.815 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 V-W-SER COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, LIFETIME-POS=LP10, 1 36. S G BUFFER-TIME=380 see below (248 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 V-W-SER COS/FUV TIME-TA PSA G160M 1577 FP-POS=ALL, LIFETIME-POS=LP10, 1 35. S G BUFFER-TIME=346 see below (244 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 V-W-SER COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=500, FP-POS=ALL, 1 46. S G LIFETIME-POS=LP10 see below (288 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-W-SER 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 1 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 2 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 3 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 4 1 62.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 1 61.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 1 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 2 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 3 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 4 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 13] Visit: 06 (V6) Visit Requirements: Period 14.18608 D AND ZERO-PHASE HJD2461775.1589 On Hold Comments: Additional Comments: Visit 6 for phase 0.821 to 0.997. 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-W-SER COS/NUV ACQ/IMA BOA MIRRORA 1 3.5 S (3.5 PHASE 0.821 TO 0.997 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 V-W-SER COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, LIFETIME-POS=LP10, 1 36. S G BUFFER-TIME=380 see below (248 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 V-W-SER COS/FUV TIME-TA PSA G160M 1577 FP-POS=ALL, LIFETIME-POS=LP10, 1 35. S G BUFFER-TIME=346 see below (244 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 V-W-SER COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=500, FP-POS=ALL, 1 46. S G LIFETIME-POS=LP10 see below (288 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-W-SER 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 1 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 2 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 3 1 62.0 S G V-W-SER 2 COS/FUV TIME-TA PSA G160M 1533 none none none 4 1 62.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 1 61.0 S G V-W-SER 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 1 61.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 1 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 14] 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-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 2 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 3 1 72.0 S G V-W-SER 4 COS/FUV TIME-TA PSA G160M 1600 none none none 4 1 72.0 S G 18356( 2) - 17-Aug-2026 15:05:29 - [ 15] Summary Form for Proposal 18356 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures BOA, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=346, BUFFER-TIME=380, BUFFER-TIME=500, FP-POS=ALL, LIFETIME-POS=LP10 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PHASE 0.00 TO 0.0916, PHASE 0.095 TO 0.270, PHASE 0.276 TO 0.452, PHASE 0.458 TO 0.634, PHASE 0.640 TO 0.815, PHASE 0.821 TO 0.997, Period 14.18608 D AND ZERO-PHASE HJD2461775.1589 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G160M, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names V-W-SER ------------------------------------------------------------------------------------------------------------------------------------