17066( 2) - 01-Jul-2022 18:09:55 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17066 Version: 2 Check-in Time: 01-Jul-2022 18:09:55 STScI Edit Number: 0 Title Unprecedented Light Element Abundances: Planetary Crusts or Icy Moons? ------------------------------------------------------------------------------------ Type Cycle GO 30 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Beth L. Klein University of California - Los Angeles Y CoI: Prof. Ben M. Zuckerman University of California - Los Angeles N CoI: Dr. Carl Melis University of California - San Diego N CoI: Dr. Alexandra Doyle University of California - Los Angeles N CoI: Dr. Patrick Dufour Universite de Montreal N CoI: Dr. Alycia J. Weinberger Carnegie Institution of Washington N CoI: Prof. Edward D. Young University of California - Los Angeles N ------------------------------------------------------------------------------------ Abstract The recent first-ever detections of the light elements, lithium and beryllium, in planetary bodies accreted by 'polluted' white dwarf stars, has prompted varied explanations regarding their origin. A remarkable aspect of the observations is that the abundance ratios of Li and Be relative to major elements are significantly overabundant -- for Be the overabundance is two orders of magnitude. On the one hand, these elements are dosimeters for radiation environments and may be giving us a measure of the degree of spallation production that has occurred while the exoplanetary bodies were forming. On the other hand, chemical processes such as igneous differentiation (i.e. crust formation) could be responsible. The last member of the set of light elements, boron, has never yet been observed in white dwarfs. We propose to conduct observations of the most promising WD that would be expected to display boron, and we can use the relative abundances of B and Be to discern between the possible formation scenarios. Furthermore, the proposed observations are expected to easily measure the volatiles, C and N, in our target stars, and provide important constraints on the planetary formation scenarios being tested. Only HST/COS can provide the required UV spectroscopy to observe B, C, and N, which are critical for this science. ------------------------------------------------------------------------------------ Observations Description ------------------------ The target is a single white dwarf, and is sufficiently faint that COS safety is not a problem. Key absorption lines for our study are: B II 1362.46 Ang, C II 1334.53/1335.71 A, and N I 1243.18/1243.31 A. Our model calculations also suggest that we are likely to detect additional important elements through transitions at Al II 1191.81, P II 1154.00/1249.83A, S I 1425.03A, S II 1253.81A, and Ni II 1317.22A. Thus we use the COS G130M grating and 1291 central wavelength setting, with both segments B and A active, providing coverage of 1137-1274 A and 1292-1432 A, respectively. In this mode only two FP-POS (3 & 4) are available, which we employ to reduce fixed pattern noise. 17066( 2) - 01-Jul-2022 18:09:55 - [ 2] Our criterion for a spectrum that can clearly distinguish between the proposed models, is a SNR of 20 near the B II 1362 A line. From the COS ETC and our model spectrum calibrated to the GALEX FUV measured flux, this goal is achieved in four orbits. To facilitate scheduling, we split our observations into two separate visits of two orbits each. ------------------------------------------------------------------------------------ 17066( 2) - 01-Jul-2022 18:09:55 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GALEXJ2339-0 STAR, DB RA=23H39M17.0285S +/- 0.000047", J2000 V = 16.16 FUV=16.83 424 DEC=-04D24'24.66" +/- 0.000044" 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 0.0016381764825929733 -0.032293 0.0112 ------------------------------------------------------------------------------------------------------------------------------------ 17066( 2) - 01-Jul-2022 18:09:55 - [ 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 GALEXJ2339- COS/FUV ACQ/PEA PSA G130M 1291 NUM-POS=3, STEP-SIZE=1.3, 1 15 S (15 0424 KXD CENTER=DEF, SEGMENT=BOTH S) ------------------------------------------------------------------------------------------------------------------------------------ 2 GALEXJ2339- COS/FUV ACQ/PEA PSA G130M 1291 CENTER=DEF, NUM-POS=5, 1 15 S (15 0424 KD STEP-SIZE=0.9, SEGMENT=BOTH S) ------------------------------------------------------------------------------------------------------------------------------------ 3 GALEXJ2339- COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=3724, FP-POS=3, 1 2257 S 0424 G SEGMENT=BOTH (2257 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 GALEXJ2339- COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=3724, FP-POS=4, 1 2686 S 0424 G SEGMENT=BOTH (2686 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 | ------------------------------------------------------------------------------------------------------------------------------------ GALEXJ2339-0424 1 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KXD GALEXJ2339-0424 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KD GALEXJ2339-0424 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G GALEXJ2339-0424 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G 17066( 2) - 01-Jul-2022 18:09:55 - [ 5] Visit: 02 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 GALEXJ2339- COS/FUV ACQ/PEA PSA G130M 1291 NUM-POS=3, STEP-SIZE=1.3, 1 15 S (15 0424 KXD CENTER=DEF, SEGMENT=BOTH S) ------------------------------------------------------------------------------------------------------------------------------------ 2 GALEXJ2339- COS/FUV ACQ/PEA PSA G130M 1291 CENTER=DEF, NUM-POS=5, 1 15 S (15 0424 KD STEP-SIZE=0.9, SEGMENT=BOTH S) ------------------------------------------------------------------------------------------------------------------------------------ 3 GALEXJ2339- COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=3724, FP-POS=3, 1 2257 S 0424 G SEGMENT=BOTH (2257 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 GALEXJ2339- COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=3724, FP-POS=4, 1 2686 S 0424 G SEGMENT=BOTH (2686 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 | ------------------------------------------------------------------------------------------------------------------------------------ GALEXJ2339-0424 1 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KXD GALEXJ2339-0424 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KD GALEXJ2339-0424 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G GALEXJ2339-0424 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G 17066( 2) - 01-Jul-2022 18:09:55 - [ 6] Summary Form for Proposal 17066 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAKD, ACQ/PEAKXD, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=3724, CENTER=DEF, FP-POS=3, FP-POS=4, NUM-POS=3, NUM-POS=5, SEGMENT=BOTH, STEP-SIZE=0.9, STEP-SIZE=1.3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M ------------------------------------------------------------------------------------------------------------------------------------ Target Names GALEXJ2339-0424 ------------------------------------------------------------------------------------------------------------------------------------