18003( 4) - 20-Nov-2025 18:07:14 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18003 Version: 4 Check-in Time: 20-Nov-2025 18:07:14 STScI Edit Number: 1 Title A Spectacularly Polluted White Dwarf with Transits ------------------------------------------------------------------------------------ Type Cycle GO 33 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Jay Farihi University College London Y CoI: Prof. Boris T. Gaensicke University of Warwick Y CoI: Prof. Seth Redfield Wesleyan University N ------------------------------------------------------------------------------------ Abstract Planetary systems orbiting white dwarfs offer not only a glimpse into the future solar system, but also a test of long-term dynamical processes spanning major stellar evolutionary transitions. These dynamical changes are epitomized by ubiquitous dust variability in the infrared, and via rapidly evolving transits detected now in at least 14 systems. Critically, the polluted stellar atmospheres distill entire exoplanetary bodies into their bulk chemical compositions, a phenomenon that is unavailable for main-sequence stars, and currently the only means to acquire empirical insight into exoplanetary surfaces and interiors. Here, we propose to study an unprecedented source with long-term transits, extreme pollution, gaseous disk emission, and a color term in multi-band light curves. The near record-breaking abundances determined from low-resolution spectroscopy imply that myriad lines of many metal species will be detected in the ultraviolet. These include but are not limited to C, N, O, Al, Si, P, S, Cr, Mn, Fe, and Ni. Multiple lines of oxygen and carbon will be detected with high confidence, and possibly nitrogen if present in sufficient quantities. These abundances directly constrain the volatile content of the parent body, and to some degree, its birthplace in this exoplanetary system, in turn constraining its origin and nature. The observed, several year transit duration suggests the parent body was initially in a relatively distant orbit where water and other ices may persist. Volatile-rich debris pollution has only been observed previously in a single case, and requires the ultraviolet capacity of Hubble for an assessment of the bulk chemical composition. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal is simply deep spectroscopy of this relatively faint targets, with the aim to detect myriad metal absorption lines from the stellar atmosphere and possbily from circumstellar material. We use two central wavelngth settings: 1222A and 1291A. The program is split into three visits: 4 orbits at 1222A, one orbit per FP-POS setting, 3 orbits at 1291A and FP-POS=3 and 3 orbits at 1291A and FP-POS=4 (for 1291A only FP-POS=3, 4 are allowed). The warning that comes up is a result of having the FP-POS=3 and 4 split over 18003( 4) - 20-Nov-2025 18:07:14 - [ 2] two visits, however, we will combine all spectroscopy in post-processing. ------------------------------------------------------------------------------------ 18003( 4) - 20-Nov-2025 18:07:14 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 WDJ1013-0427 STAR, DB, DZ RA=10H13M6.3239S +/- 0.00039", J2000 V = 18.25 +/- 0.05 GALEX FUV=17.920 DEC=-04D27'29.55" +/- 0.00064" Reference Frame: ICRS Extended: NO Comments: Coordinates and astrometry up to date using Gaia DR3 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2016.0 -1.1728821265720618E-4 -0.019873000000000002 0.0032469 ------------------------------------------------------------------------------------------------------------------------------------ 18003( 4) - 20-Nov-2025 18:07:14 - [ 4] Visit: 01 (1291A - FP-POS=3) 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 WDJ1013-042 COS/NUV ACQ/IMA PSA MIRRORA 1 3 S (3 S) 7 GE ------------------------------------------------------------------------------------------------------------------------------------ 2 WDJ1013-042 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=2445, FP-POS=3 1 2163 S 7 G (2163 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WDJ1013-042 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=2445, FP-POS=3 1 2539 S 7 G (2539 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WDJ1013-042 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=2445, FP-POS=3 1 2539 S 7 G (2539 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ1013-0427 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE WDJ1013-0427 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G WDJ1013-0427 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G WDJ1013-0427 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 N/A G 18003( 4) - 20-Nov-2025 18:07:14 - [ 5] Visit: 02 (1291A - FP-POS=4) 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 WDJ1013-042 COS/NUV ACQ/IMA PSA MIRRORA 1 3 S (3 S) 7 GE ------------------------------------------------------------------------------------------------------------------------------------ 2 WDJ1013-042 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=2445, FP-POS=4 1 2163 S 7 G (2163 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WDJ1013-042 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=2445, FP-POS=4 1 2539 S 7 G (2539 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WDJ1013-042 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=2445, FP-POS=4 1 2539 S 7 G (2539 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ1013-0427 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE WDJ1013-0427 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G WDJ1013-0427 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G WDJ1013-0427 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 N/A G 18003( 4) - 20-Nov-2025 18:07:14 - [ 6] Visit: 03 (1222A - all four FP-POS) 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 WDJ1013-042 COS/NUV ACQ/IMA PSA MIRRORA 1 3 S (3 S) 7 GE ------------------------------------------------------------------------------------------------------------------------------------ 2 WDJ1013-042 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2163, FP-POS=1 1 2077 S 7 G (2077 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WDJ1013-042 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2539, FP-POS=2 1 2539 S 7 G (2539 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WDJ1013-042 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2539, FP-POS=3 1 2539 S 7 G (2539 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 WDJ1013-042 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=2539, FP-POS=4 1 2539 S 7 G (2539 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ1013-0427 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE WDJ1013-0427 2 COS/FUV TIME-TA PSA G130M 1222 none none none none 1 N/A G WDJ1013-0427 3 COS/FUV TIME-TA PSA G130M 1222 none none none none 2 N/A G WDJ1013-0427 4 COS/FUV TIME-TA PSA G130M 1222 none none none none 3 N/A G WDJ1013-0427 5 COS/FUV TIME-TA PSA G130M 1222 none none none none 4 N/A G 18003( 4) - 20-Nov-2025 18:07:14 - [ 7] Summary Form for Proposal 18003 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=2163, BUFFER-TIME=2445, BUFFER-TIME=2539, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names WDJ1013-0427 ------------------------------------------------------------------------------------------------------------------------------------