17422( 4) - 15-Aug-2024 19:29:35 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17422 Version: 4 Check-in Time: 15-Aug-2024 19:29:35 STScI Edit Number: 1 Title Bulk abundances of the planetary material in a nearby bright gaseous disk around a white ------------------------------------------------------------------------------------ Type Cycle GO 31 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Boris T. Gaensicke University of Warwick Y CoI: Dr. Odette Fabiola Toloza Universidad Tecnica Federico Santa Maria N Castillo CoI: Prof. Matthias R. Schreiber Universidad Tecnica Federico Santa Maria N CoI: Dr. Keith Inight University of Warwick N CoI: Dr. JJ Hermes Boston University N CoI: Dr. Warren R. Brown Smithsonian Institution Astrophysical N Observatory CoI: Dr. Gagik Tovmasian Universidad Nacional Autonoma de Mexico N (UNAM) ------------------------------------------------------------------------------------ Abstract The remnants of planetary systems that survived the metamorphosis of their host stars into white dwarfs are identified in the form of compact debris disks, formed from the tidal disruption of planetesimals. These disks are detectable as IR flux excess, and, in rare occasions, as metallic emission lines from a gaseous disk component in optical spectra. These gaseous disks are thought to host embedded solid fragments, maybe the core, of the disrupted planetesimal, and represent ideal targets for joint ultraviolet, optical and infrared observations that provide unrivalled insight into the formation of these disks, the nature of the disrupting planetesimal, the elemental abundances of the planetary debris, and its mineralogical make-up. Here, we propose COS far-ultraviolet spectroscopy of a new, bright, and nearby gaseous disk system to measure the elemental abundances of the planetary material. The far-ultraviolet wavelength range is critically important to access transitions of core (Cr, Fe, Ni), mantle (Si, Mg, O), and crust (Ca, Al), as well as volatiles (C, S, P) species that have no transitions at optical wavelengths, or are contaminated by the disk emission lines. This system is also a prime target for JWST MIRI spectroscopy of the circumstellar dust, and these COS observations will ensure that the composition of the debris is known well in time for the next JWST proposal round. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of these COS observations is to obtain COS/G130M FUV spectroscopy of the hydrogen-atmosphere DA white dwarf WDJ062500.08+413410.73, which has an effective temperature of ~17500K. The observations are split across two G130M central wavelength settings, 1291A and 1222A, which are obtained over two 5-orbit visits. Visit 1 will obtain the 1291A data, which can only make use of the FP-POS=3 & 4 17422( 4) - 15-Aug-2024 19:29:35 - [ 2] setups (as per COS 2025 policy), the exposure time is split equally across these two settings. Visit 2 (1222A) uses FP-POS=1, 2, 3, 4, again, the time is split equally across the four settings. A warning regarding inefficient FP-POS changes can be ignored, as the change from FP-POS=4 back to 1 occurs during Earth occlutation between orbit 4 and 5. Apart from impacting the schedulability of this program, we do not foresee any negative effect should HST drop to a 2-gyro mode. The ETC similations were carried out with a DA model for Teff=17500K, log g=7.7, as per https://ui.adsabs.harvard.edu/abs/2021MNRAS.508.3877G Update 2023-10-25: deleted a spurious "Visit Orientation Requirement" in Visit 01. ------------------------------------------------------------------------------------ 17422( 4) - 15-Aug-2024 19:29:35 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 WDJ062500.08 STAR, DA RA=06H25M0.0798S +/- 0.05", J2000 V = 17.8 +/- 0.1 GALEX FUV=17.3 +413410.73 DEC=+41D34'10.73" +/- 0.05" Reference Frame: ICRS Extended: NO Comments: Teff~17500K Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -0.002951637424600302 -0.025783999999999998 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 17422( 4) - 15-Aug-2024 19:29:35 - [ 4] Visit: 01 (COS spectroscopy, G130M @ 1291A) Visit Requirements: On Hold Comments: Additional Comments: Only two FP-POS settings allowed for the 1291A central wavelength. 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 WDJ062500.0 COS/NUV ACQ/IMA PSA MIRRORB 1 15 S (15 8+413410.73 GE S) Comments: For an alternative ETC simulation using a model spectrum, see https://etc.stsci.edu/etc/results/COS.ta.1888 313/ ------------------------------------------------------------------------------------------------------------------------------------ 2 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1000, FP-POS=3 1 2430 S 8+413410.73 G see below (2326 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1000, FP-POS=3 1 2760 S 8+413410.73 G see below (2605 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1223, FP-POS=3 1 1330 S 8+413410.73 G see below (1210 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1000, FP-POS=4 1 1325 S 8+413410.73 G see below (1205 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1000, FP-POS=4 1 2760 S 8+413410.73 G see below (2605 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1000, FP-POS=4 1 2760 S 8+413410.73 G see below (2605 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ062500.08+413410 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A .73 GE WDJ062500.08+413410 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 2326.0 S .73 G 17422( 4) - 15-Aug-2024 19:29:35 - [ 5] 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ062500.08+413410 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 2605.0 S .73 G WDJ062500.08+413410 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 1210.0 S .73 G WDJ062500.08+413410 5 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 1205.0 S .73 G WDJ062500.08+413410 6 COS/FUV TIME-TA PSA G130M 1291 none none none none 4 2605.0 S .73 G WDJ062500.08+413410 7 COS/FUV TIME-TA PSA G130M 1291 none none none none 5 2605.0 S .73 G 17422( 4) - 15-Aug-2024 19:29:35 - [ 6] Visit: 02 (COS spectroscopy, G130M @ 1222A) 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 WDJ062500.0 COS/NUV ACQ/IMA PSA MIRRORB 1 15 S (15 8+413410.73 GE S) Comments: For an alternative ETC simulation using a model spectrum, see https://etc.stsci.edu/etc/results/COS.ta.1888 313/ ------------------------------------------------------------------------------------------------------------------------------------ 2 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1169, FP-POS=1 1 2416 S 8+413410.73 G see below (2312 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1180, FP-POS=2 1 2760 S 8+413410.73 G see below (2605 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1304, FP-POS=3 1 2760 S 8+413410.73 G see below (2605 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1304, FP-POS=4 1 2760 S 8+413410.73 G see below (2605 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=485, FP-POS=1 1 597 S 8+413410.73 G see below (508 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=485, FP-POS=2 1 597 S 8+413410.73 G see below (508 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=485, FP-POS=3 1 597 S 8+413410.73 G see below (508 S) ------------------------------------------------------------------------------------------------------------------------------------ 9 WDJ062500.0 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=485, FP-POS=4 1 597 S 8+413410.73 G see below (508 S) ------------------------------------------------------------------------------------------------------------------------------------ 17422( 4) - 15-Aug-2024 19:29:35 - [ 7] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ062500.08+413410 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A .73 GE WDJ062500.08+413410 2 COS/FUV TIME-TA PSA G130M 1222 none none none none 1 2312.0 S .73 G WDJ062500.08+413410 3 COS/FUV TIME-TA PSA G130M 1222 none none none none 2 2605.0 S .73 G WDJ062500.08+413410 4 COS/FUV TIME-TA PSA G130M 1222 none none none none 3 2605.0 S .73 G WDJ062500.08+413410 5 COS/FUV TIME-TA PSA G130M 1222 none none none none 4 2605.0 S .73 G WDJ062500.08+413410 6 COS/FUV TIME-TA PSA G130M 1222 none none none none 5 508.0 S .73 G WDJ062500.08+413410 7 COS/FUV TIME-TA PSA G130M 1222 none none none none 5 508.0 S .73 G WDJ062500.08+413410 8 COS/FUV TIME-TA PSA G130M 1222 none none none none 5 508.0 S .73 G WDJ062500.08+413410 9 COS/FUV TIME-TA PSA G130M 1222 none none none none 5 508.0 S .73 G 17422( 4) - 15-Aug-2024 19:29:35 - [ 8] Summary Form for Proposal 17422 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1000, BUFFER-TIME=1169, BUFFER-TIME=1180, BUFFER-TIME=1223, BUFFER-TIME=1304, BUFFER-TIME=485, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names WDJ062500.08+413410.73 ------------------------------------------------------------------------------------------------------------------------------------