16502( 3) - 14-Apr-2021 13:42:49 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16502 Version: 3 Check-in Time: 14-Apr-2021 13:42:49 STScI Edit Number: 1 Title Bulk abundances of the planetary material in a nearby bright gaseous disk around a white dwarf ------------------------------------------------------------------------------------ Type Cycle GO 28 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Boris T. Gaensicke The University of Warwick Y CoI: Dr. Odette Fabiola Toloza The University of Warwick N Castillo CoI: Prof. Matthias R. Schreiber Universidad de Valparaiso N CoI: Mr. Keith Inight The University of Warwick N ------------------------------------------------------------------------------------ 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 that we identified in December 2020, to measure the elemental abundances of the planetary material. The far-ultraviolet wavelength range is critically important to access transitions of core (Fe, Ni), mantle (Si, Mg, O), and crust (Ca, Al), as well as volatiles (C, N, 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 Cycle 2 MIRI spectroscopy of the circumstellar dust, and this mid-cycle program will ensure that the composition of the debris is known well in time for the next JWST proposal round. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of this proposal is to obtain full spectroscopic coverage over ~1100 - 1430A. For this purpose, we will use the G130M grating with two different central wavelengths, 1291A and 1222A. At each central wavelength, we use all available FP-POS settings to mitigate fixed pattern noise. The target is a single white dwarf, not variable, and an acquisition with NUV imaging using MIRROR-B is safe and efficient. We split the @1291A and @1222A observations into two separate visits to facilitate the scheduling. We obtained a Swift ToO UVOT UVW2 observation of the target 16502( 3) - 14-Apr-2021 13:42:49 - [ 2] https://www.swift.psu.edu/operations/obsSchedule.php?t=14167& perc=1 to establish the UV flux to be 2.1e-14A @ 1928A (see below). The intrinsic spectrum of this white dwarf is close to a blackbody with Teff=20500K, which we adopted for the ETC calculations, scaled to the Swift UVW2 flux. uvotsource: Source Position: RA = 00h 05m 45.13s, Dec = +58d 05m 39.0s (J2000) Position: RA = 1.43806, Dec = 58.09418 (J2000) Exposure: 654.53 s Filter: UVW2 Significance: 136.0 sigma (stat) Background-limit: 3.0 sigma (stat) uvotsource: UVOT uvw2 magnitude (AB system) Source: 15.25 +/- 0.02 (stat) +/- 0.03 (sys) Background: 24.22 arcsec^-2 Background-limit: 21.04 Coincidence-limit: 12.68 uvotsource: Flux density [erg/s/cm^2/A] Source: 2.08 +/- 0.04 (stat) +/- 0.05 (sys) x 10^-14 Background: 5.41 +/- 0.04 (stat) +/- 0.12 (sys) x 10^-18 arcsec^-2 Background-limit: 1.01 x 10^-16 Coincidence-limit: 2.22 x 10^-13 ------------------------------------------------------------------------------------ 16502( 3) - 14-Apr-2021 13:42:49 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 WDJ000545.13 STAR, DB RA=00H05M45.1323S +/- 0.05", J2000 V = 15.7 Swift +580538.24 DEC=+58D05'38.24" +/- 0.05" uvw2(lambda_eff=1928A)=15.25 AB mag Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0021978026367664876 0.017783 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 16502( 3) - 14-Apr-2021 13:42:49 - [ 4] Visit: 01 (COS spectroscopy, G130M @ 1291, 1222A) 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 WDJ000545.1 COS/NUV ACQ/IMA PSA MIRRORB 1 3 S (3 S) 3+580538.24 GE ------------------------------------------------------------------------------------------------------------------------------------ 2 WDJ000545.1 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1000, FP-POS=3 1 2678 S 3+580538.24 G (2678 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WDJ000545.1 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1000, FP-POS=4 1 2933 S 3+580538.24 G (2933 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ000545.13+580538 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A .24 GE WDJ000545.13+580538 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A .24 G WDJ000545.13+580538 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A .24 G 16502( 3) - 14-Apr-2021 13:42:49 - [ 5] 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 WDJ000545.1 COS/NUV ACQ/IMA PSA MIRRORB 1 3 S (3 S) 3+580538.24 GE ------------------------------------------------------------------------------------------------------------------------------------ 2 WDJ000545.1 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1169, FP-POS=1 1 1279 S 3+580538.24 G (1279 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WDJ000545.1 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1180, FP-POS=2 1 1279 S 3+580538.24 G (1279 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WDJ000545.1 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1304, FP-POS=3 1 1414 S 3+580538.24 G (1414 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 WDJ000545.1 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1304, FP-POS=4 1 1414 S 3+580538.24 G (1414 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ000545.13+580538 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A .24 GE WDJ000545.13+580538 2 COS/FUV TIME-TA PSA G130M 1222 none none none none 1 N/A .24 G WDJ000545.13+580538 3 COS/FUV TIME-TA PSA G130M 1222 none none none none 1 N/A .24 G WDJ000545.13+580538 4 COS/FUV TIME-TA PSA G130M 1222 none none none none 2 N/A .24 G WDJ000545.13+580538 5 COS/FUV TIME-TA PSA G130M 1222 none none none none 2 N/A .24 G 16502( 3) - 14-Apr-2021 13:42:49 - [ 6] Summary Form for Proposal 16502 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=1304, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names WDJ000545.13+580538.24 ------------------------------------------------------------------------------------------------------------------------------------