16169( 2) - 22-Jun-2020 15:19:44 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16169 Version: 2 Check-in Time: 22-Jun-2020 15:19:44 STScI Edit Number: 0 Title The biological potential of other worlds: comparing the phosphorus content of wet and dry exoplanetary crusts ------------------------------------------------------------------------------------ Type Cycle GO 28 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Carl Melis University of California - San Diego Y CoI: Dr. Patrick Dufour Universite de Montreal N CoI: Dr. Alycia J. Weinberger Carnegie Institution of Washington N CoI: Dr. Beth Klein University of California - Los Angeles N CoI: Dr. Siyi Xu Gemini Observatory, Northern Operations N CoI: Prof. Ben M. Zuckerman University of California - Los Angeles N CoI: Allie Schneider University of California - Los Angeles N ------------------------------------------------------------------------------------ Abstract Life on Earth as we know it requires water and reliable access to phosphorus to drive basic biological processes. Studies of polluted white dwarf stars are able to detect both water and phosphorus in the accreted material from their extant planetary systems. In this proposal we seek to carefully examine the phosphorus content of a set of polluted white dwarf stars that are accreting the crust and mantle regions (the surface) of massive, differentiated rocky bodies. COS FUV spectroscopic observations of three white dwarf stars -- one water-rich and two relatively water-poor -- along with available data for another water-rich white dwarf will allow us to robustly assess their phosphorus content and compare the biological potential of very wet and more Earth-like worlds. ------------------------------------------------------------------------------------ Observations Description ------------------------ Our primary goal is to detect or tightly constrain phosphorus for three polluted white dwarf stars: GD 61, SDSSJ0731+2417, and SDSSJ1043+0855. A secondary goal is to measure carbon to a sufficient level in SDSSJ0731+2417 as it cannot be characterized from optical data. Modeling of absorption lines shows that phosphorus has its strongest transitions for the target stars near 1540 Angstroms. Carbon can be measured or sufficiently strongly constrained with observations in the 1130-1433 Angstrom range. We will perform medium spectral resolution ultraviolet spectroscopy with COS and the G160M grating to cover the 1410-1800 Angstrom range for all three targets to measure phosphorus and with the G130M grating to cover the 1130-1433 Angstrom range to measure carbon in SDSSJ0731+2417. For the measured UV flux of each target (given in their information areas) and based on past COS observations of GD 61 and SDSSJ1043+0855 we expect to obtain near the 1540 Angstrom phosphorus transition S/N~15 for SDSSJ1043+0855 (2 orbits), S/N~22 for SDSSJ0731+2417 (2 orbits), and S/N~22 for GD 61 (1 orbit). Near the 1330 carbon transition for SDSSJ0731+2417 we expect to obtain S/N~15 (1 orbit). These estimates are made using the COS ETC assuming standard background parameters and with a white dwarf spectral energy 16169( 2) - 22-Jun-2020 15:19:44 - [ 2] distribution matched to the parameters and flux level of our targets. These signal-to-noise ratios will enable detection or tight limits on the abundances of phosphorus for all targets and additionally carbon for SDSSJ0731+2417. Our requested time estimates for COS are increased assuming 20 minutes of instrument overhead (including all acquisition and exposure overheads as suggested in the COS manual) per visit and 6 minutes of observatory overhead per orbit (spacecraft acquisition). In sum, we request a total of 6 orbits for this project. Observations will be done in the TIME-TAG mode using TAG-FLASH wavelength calibration. Each white dwarf is an ICRS object (Gaia DR2 position with less than 0.4" positional uncertainty), has a measured UV flux, and is safe for the COS detectors in our desired setups. Reduced-gyro impact: we do not forsee any significant impact on this program due to reduced-gyro operations. Each visit has a wide range of observing windows, loss of ~50% of these would still leave ample opportunity to obtain each target. There are no orientation restrictions for this program nor does it use spatial scanning. ------------------------------------------------------------------------------------ 16169( 2) - 22-Jun-2020 15:19:44 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GD-61 STAR, DB RA=04H38M39.3810S +/- J2000 V = 14.879 +/- 0.01 mNUV=14.70+/-0.05 0.0000514", DEC=+41D09'30.65" +/- 0.0000412" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 4.6930170375668193E-4 -0.10934999999999999 0.0186 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ0731+24 STAR, DA RA=07H31M10.3361S +/- J2000 V = 16.3 +/- 0.01 mFUV=16.02+/-0.05 17 0.0000687", DEC=+24D17'3.05" +/- 0.0000616" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 -0.0014481355810677132 -0.0911 0.0088 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ1043+08 STAR, DA RA=10H43M41.5753S +/- J2000 V = 17 +/- 0.01 mFUV=16.92+/-0.05 55 0.0001437", DEC=+08D55'57.60" +/- 0.0001567" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 0.002854622290782613 -0.0479 0.0057 ------------------------------------------------------------------------------------------------------------------------------------ 16169( 2) - 22-Jun-2020 15:19:44 - [ 4] Visit: 01 (GD61phos) Visit Requirements: On Hold Comments: Additional Comments: G160M grating observations of GD 61. 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 GD-61 COS/NUV ACQ/IMA BOA MIRRORA 1 32 S (32 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 GD-61 COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=1685, FP-POS=ALL, 1 511 S G FLASH=YES (2044 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 | ------------------------------------------------------------------------------------------------------------------------------------ GD-61 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE GD-61 2 COS/FUV TIME-TA PSA G160M 1600 none none none 1 1 N/A G GD-61 2 COS/FUV TIME-TA PSA G160M 1600 none none none 2 1 N/A G GD-61 2 COS/FUV TIME-TA PSA G160M 1600 none none none 3 1 N/A G GD-61 2 COS/FUV TIME-TA PSA G160M 1600 none none none 4 1 N/A G 16169( 2) - 22-Jun-2020 15:19:44 - [ 5] Visit: 02 (SDSS0731PHOS) Visit Requirements: On Hold Comments: Additional Comments: G160M grating observations of SDSSJ0731+2417. 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 SDSSJ0731+2 COS/NUV ACQ/IMA PSA MIRRORB 1 15 S (15 417 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ0731+2 COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=3885, FP-POS=ALL, 1 1000 S 417 G FLASH=YES see below (4826 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ0731+2417 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE SDSSJ0731+2417 2 COS/FUV TIME-TA PSA G160M 1600 none none none 1 1 1125.0 S G SDSSJ0731+2417 2 COS/FUV TIME-TA PSA G160M 1600 none none none 2 1 1125.0 S G SDSSJ0731+2417 2 COS/FUV TIME-TA PSA G160M 1600 none none none 3 2 1288.0 S G SDSSJ0731+2417 2 COS/FUV TIME-TA PSA G160M 1600 none none none 4 2 1288.0 S G 16169( 2) - 22-Jun-2020 15:19:44 - [ 6] Visit: 03 (SDSS1043PHOS) Visit Requirements: On Hold Comments: Additional Comments: G160M grating observations of SDSSJ1043+0855. 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 SDSSJ1043+0 COS/NUV ACQ/IMA PSA MIRRORB 1 15 S (15 855 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ1043+0 COS/FUV TIME-TA PSA G160M 1600 BUFFER-TIME=2520, FP-POS=ALL, 1 1000 S 855 G FLASH=YES see below (4774 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ1043+0855 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE SDSSJ1043+0855 2 COS/FUV TIME-TA PSA G160M 1600 none none none 1 1 1114.0 S G SDSSJ1043+0855 2 COS/FUV TIME-TA PSA G160M 1600 none none none 2 1 1114.0 S G SDSSJ1043+0855 2 COS/FUV TIME-TA PSA G160M 1600 none none none 3 2 1273.0 S G SDSSJ1043+0855 2 COS/FUV TIME-TA PSA G160M 1600 none none none 4 2 1273.0 S G 16169( 2) - 22-Jun-2020 15:19:44 - [ 7] Visit: 04 (SDSS0731C) Visit Requirements: On Hold Comments: Additional Comments: G130M grating observations of SDSSJ0731+2417. 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 SDSSJ0731+2 COS/NUV ACQ/IMA PSA MIRRORB 1 15 S (15 417 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ0731+2 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=2575, FP-POS=3, 1 1144 S 417 G FLASH=YES (1144 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ0731+2 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=2575, FP-POS=4, 1 1144 S 417 G FLASH=YES (1144 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ0731+2417 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE SDSSJ0731+2417 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G SDSSJ0731+2417 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G 16169( 2) - 22-Jun-2020 15:19:44 - [ 8] Summary Form for Proposal 16169 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures BOA, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1685, BUFFER-TIME=2520, BUFFER-TIME=2575, BUFFER-TIME=3885, FLASH=YES, FP-POS=3, FP-POS=4, FP-POS=ALL ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, G160M, MIRRORA, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names GD-61, SDSSJ0731+2417, SDSSJ1043+0855 ------------------------------------------------------------------------------------------------------------------------------------