15474( 7) - 21-Aug-2018 13:28:29 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15474 Version: 7 Check-in Time: 21-Aug-2018 13:28:29 STScI Edit Number: 4 Title Water Delivery in Extrasolar Systems: Accretion of Water-Rich Debris onto a Spectacularly Polluted White Dwarf ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Mr. Matthew John Hoskin The University of Warwick Y CoI: Prof. Detlev G. Koester Universitat Kiel N CoI: Dr. Odette Fabiola Toloza The University of Warwick N Castillo CoI: Dr. Roberto Raddi Universitat Erlangen-Nurnberg N CoI: Dr. Jay Farihi University College London N CoI: Prof. Boris T. Gaensicke The University of Warwick Y ------------------------------------------------------------------------------------ Abstract Kuiper belt objects are the best candidate source of water and volatile elements delivered to terrestrial planets early in the solar system. Determining the prevalence of this architecture in the galaxy is fundamental to modelling the frequency of habitable planets. We propose to examine a system showing remarkable water content, and discover the origin of its water-bearing rocky material. White dwarf APASS J2047-1259 exhibits absorption features of both rock-forming and volatile elements. COS Snapshot observations have detected a large oxygen excess, while optical spectra show the extraordinary hydrogen fraction (5% by mass) of the helium atmosphere, beyond explanation by continuous evolution. That the star has undergone accretion is beyond question, but the history of the pollutant material is yet to be determined. A detection of nitrogen would indicate cometary origin, providing firm evidence of hydrogen pollution of white dwarfs from objects formed well beyond the snow line. We apply for five HST orbits in order to be sensitive to relevant abundances of volatiles that would classify the accreted material. We will also gain a precise measurement of the abundance of oxygen and other elements, allowing a confident determination of the composition and oxygen excess of the accreted material, and thus constraining the mass of water accreted by this star. The results will not only impact understandings of white dwarf atmospheric evolution, but will further our knowledge of the ubiquity and history of water in planetary systems around Sun-like stars. ------------------------------------------------------------------------------------ Observations Description ------------------------ The purpose of these COS observations are to obtain a high signal-to-noise ratio of the white dwarf APASS2047, which is accreting volatile rich planetary debris. Key lines for this study are N I 1200A, O I 1150A, and multiple lines of S and P. To maximise the S/N, we use two FP-POS settings @ 1291A, and three @ 1222A. The 1222A observations will extend the wavelength coverage into the red wing of Ly beta, which will provide additional constraints on the effective temperature, and allow to probe for the presence / absence of the 15474( 7) - 21-Aug-2018 13:28:29 - [ 2] quasi-molecular Ly beta line near 1175A. Changes: 21 August 2018: As discussed with Nick, we now split the @ 1222A observations across all four FP-POS settings, double-checked the ETC simulations, modified the buffer times accordingly. ------------------------------------------------------------------------------------ 15474( 7) - 21-Aug-2018 13:28:29 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 APASSJ204713 STAR, DA RA=20H47M13.8208S +/- 0.0632", J2000 V = 15.85 +/- 0.1 GALEX FUV=15.59, .82-125909.5 DEC=-12D59'8.65" +/- 0.0436" observed with COS (LDNU0R010), F(1300A)=3e-14erg/cm2/s/A 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 0.004152393150597149 0.019074 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 15474( 7) - 21-Aug-2018 13:28:29 - [ 4] Visit: 02 (APASSJ204713.82-125909.5) 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 APASSJ20471 COS/FUV ACQ/PEA PSA G130M 1291 1 5 S (5 S) 3.82-125909 KXD .5 ------------------------------------------------------------------------------------------------------------------------------------ 2 APASSJ20471 COS/FUV ACQ/PEA PSA G130M 1291 STEP-SIZE=0.9, NUM-POS=5, 1 5 S (5 S) 3.82-125909 KD CENTER=DEF .5 ------------------------------------------------------------------------------------------------------------------------------------ 3 APASSJ20471 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1200, FLASH=YES, 1 2464 S 3.82-125909 G FP-POS=3 (2464 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 4 APASSJ20471 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1177, FLASH=YES, 1 2923 S 3.82-125909 G FP-POS=4 (2923 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 5 APASSJ20471 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1000, FLASH=YES, 1 2111 S 3.82-125909 G FP-POS=1 (2111 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 6 APASSJ20471 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=597, FLASH=YES, 1 707 S (707 3.82-125909 G FP-POS=2 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 7 APASSJ20471 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1294, FLASH=YES, 1 1404 S 3.82-125909 G FP-POS=2 (1404 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 8 APASSJ20471 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1304, FLASH=YES, 1 1414 S 3.82-125909 G FP-POS=3 (1414 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 9 APASSJ20471 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=587, FLASH=YES, 1 697 S (697 3.82-125909 G FP-POS=3 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 10 APASSJ20471 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=1000, FLASH=YES, 1 2111 S 3.82-125909 G FP-POS=4 (2111 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 15474( 7) - 21-Aug-2018 13:28:29 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ APASSJ204713.82-125 1 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A 909.5 KXD APASSJ204713.82-125 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A 909.5 KD APASSJ204713.82-125 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A 909.5 G APASSJ204713.82-125 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A 909.5 G APASSJ204713.82-125 5 COS/FUV TIME-TA PSA G130M 1222 none none none none 3 N/A 909.5 G APASSJ204713.82-125 6 COS/FUV TIME-TA PSA G130M 1222 none none none none 3 N/A 909.5 G APASSJ204713.82-125 7 COS/FUV TIME-TA PSA G130M 1222 none none none none 4 N/A 909.5 G APASSJ204713.82-125 8 COS/FUV TIME-TA PSA G130M 1222 none none none none 4 N/A 909.5 G APASSJ204713.82-125 9 COS/FUV TIME-TA PSA G130M 1222 none none none none 5 N/A 909.5 G APASSJ204713.82-125 10 COS/FUV TIME-TA PSA G130M 1222 none none none none 5 N/A 909.5 G 15474( 7) - 21-Aug-2018 13:28:29 - [ 6] Summary Form for Proposal 15474 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAKD, ACQ/PEAKXD, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1000, BUFFER-TIME=1177, BUFFER-TIME=1200, BUFFER-TIME=1294, BUFFER-TIME=1304, BUFFER-TIME=587, BUFFER-TIME=597, CENTER=DEF, FLASH=YES, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, NUM-POS=5, STEP-SIZE=0.9 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M ------------------------------------------------------------------------------------------------------------------------------------ Target Names APASSJ204713.82-125909.5 ------------------------------------------------------------------------------------------------------------------------------------