13719( 9) - 14-May-2015 16:26:58 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13719 Version: 9 Check-in Time: 14-May-2015 16:26:58 STScI Edit Number: 6 Title Accretion of planetary debris onto the unique white dwarf GD394 ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Mr. David John Wilson The University of Warwick Y CoI: Prof. Boris T. Gaensicke The University of Warwick N CoI: Dr. Knox S. Long Eureka Scientific Inc. N CoI: Prof. Detlev G. Koester Universitat Kiel N CoI: Dr. Matthew Burleigh University of Leicester N CoI: Prof. Martin Barstow University of Leicester N CoI: Dr. Simon Paul Preval University of Strathclyde N CoI: Dr. Jay B. Holberg University of Arizona N CoI: Dr. Sarah Casewell University of Leicester N ------------------------------------------------------------------------------------ Abstract It is now undisputed that metal-pollution of the H or He atmospheres observed in a substantial fraction of white dwarfs is due to accretion of planetary debris. While significant progress has been made in establishing the frequency of such evolved planetary systems, and statistics on the abundances of the debris material are beginning to emerge, very little is known regarding the delivery mechanism of the debris. Given that the red giant progenitors of the metal-polluted white dwarfs evaporated all planetary material within >1 AU, the debris found at many white dwarfs must originate originally from a substantial distance of the star. The canonical model is that remaining planets perturb the orbits of astroids, sending them onto a white dwarf grazing course, where the extreme gravity will result in their tidal disruption. The debris then must undergo complex dynamical evolution, and eventually fall into the white dwarf atmosphere. EUV light curves of GD394, an extremely metal-polluted white dwarf, suggest a strong variation of the metal abundances over the stellar surface. We propose to obtain spin-phase resolved high-resolution spectroscopy of GD394 over its 1.15d rotation period to resolve the abundance pattern on its surface from variations in the photospheric metal lines, and thereby probe the geometry of the circumstellar debris. Line profile variations can be used to reconstruct the surface distribution of the metals using Roche tomography. In addition, comparison to a single archive HST/GHRS observation from 1992 will place tight constraints on the long-term variation of the accretion rate, and the life time of the circumstellar debris. ------------------------------------------------------------------------------------ Observations Description ------------------------ The target of this program is a young hydrogen-atmosphere white dwarf that has a rotational period of 1.150+-0.003d, and shows photospheric contamination by metals in the HST and FUSE spectra. The aim of the STIS/E140M observations is to obtain spin-phase resolved high-resolution FUV spectroscopy sampling the entire rotation cycle, to probe for variations in the photospheric abundances. 13719( 9) - 14-May-2015 16:26:58 - [ 2] Each individual 8 phase visits is one STIS orbit, centred on phases 0.0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875. We allow for a 0.03 phase uncertainty to ease the scheduling, however, given that the period is not extremely accurately known, we group all 8 visits to be scheduled within 5 days to avoid the additional accumulation of phase error. ------------------------------------------------------------------------------------ 13719( 9) - 14-May-2015 16:26:58 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GD-394 STAR, DA RA=21H12M44.0460S +/- 0.07", J2000 V = 13.09 DEC=+50D06'17.86" +/- 0.07" Reference Frame: ICRS Comments: GD 394 is a DA white dwarf with Teff=39660+-636K, log g=7.88+-0.05 (Gianninas et al. 2011ApJ...743..138G). It has a well-established and stable FUV flux, based on observations with IUE (swp41457, swp14296), HST/STIS (Z0YE0A0CM, Z0YE0A0AM, Z0YE0A08M). F(1300A)=3e-12 erg/cm2/s/A. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.009333993542777745 -0.0173 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 13719( 9) - 14-May-2015 16:26:58 - [ 4] Visit: 01 Visit Requirements: Period 1.150 D AND ZERO-PHASE HJD2450004.818; GROUP 01, 02, 03, 04, 05, 06, 07, 08 WITHIN 5D 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 GD-394 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.1 S (0.1 PHASE 0.0 TO 0.03; GS S) ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 GD-394 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=99 1 2595 S -MAMA G (2595 S) Comments: The ETC simulation STIS.sp.622199 gives a "Count rate entire detector" of 14300 cts/s, i.e. a buffer time of 133sec. To be on the safe side, I opted for a margin of ~30%, and use the shortest possible buffer time (99sec). ------------------------------------------------------------------------------------------------------------------------------------ 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-394 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A GD-394 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G 13719( 9) - 14-May-2015 16:26:58 - [ 5] Visit: 02 Visit Requirements: Period 1.150 D AND ZERO-PHASE HJD2450004.818 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 GD-394 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.1 S (0.1 PHASE 0.125 TO 0.155; GS S) ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 GD-394 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=99 1 2595 S -MAMA G (2595 S) Comments: The ETC simulation STIS.sp.622199 gives a "Count rate entire detector" of 14300 cts/s, i.e. a buffer time of 133sec. To be on the safe side, I opted for a margin of ~30%, and use the shortest possible buffer time (99sec). ------------------------------------------------------------------------------------------------------------------------------------ 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-394 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A GD-394 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G 13719( 9) - 14-May-2015 16:26:58 - [ 6] Visit: 03 Visit Requirements: Period 1.150 D AND ZERO-PHASE HJD2450004.818 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 GD-394 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.1 S (0.1 PHASE 0.25 TO 0.28; GS S) ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 GD-394 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=99 1 2595 S -MAMA G (2595 S) Comments: The ETC simulation STIS.sp.622199 gives a "Count rate entire detector" of 14300 cts/s, i.e. a buffer time of 133sec. To be on the safe side, I opted for a margin of ~30%, and use the shortest possible buffer time (99sec). ------------------------------------------------------------------------------------------------------------------------------------ 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-394 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A GD-394 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G 13719( 9) - 14-May-2015 16:26:58 - [ 7] Visit: 04 Visit Requirements: Period 1.150 D AND ZERO-PHASE HJD2450004.818 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 GD-394 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.1 S (0.1 PHASE 0.375 TO 0.405; GS S) ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 GD-394 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=99 1 2595 S -MAMA G (2595 S) Comments: The ETC simulation STIS.sp.622199 gives a "Count rate entire detector" of 14300 cts/s, i.e. a buffer time of 133sec. To be on the safe side, I opted for a margin of ~30%, and use the shortest possible buffer time (99sec). ------------------------------------------------------------------------------------------------------------------------------------ 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-394 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A GD-394 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G 13719( 9) - 14-May-2015 16:26:58 - [ 8] Visit: 05 Visit Requirements: Period 1.150 D AND ZERO-PHASE HJD2450004.818 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 GD-394 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.1 S (0.1 PHASE 0.5 TO 0.53; GS S) ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 GD-394 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=99 1 2595 S -MAMA G (2595 S) Comments: The ETC simulation STIS.sp.622199 gives a "Count rate entire detector" of 14300 cts/s, i.e. a buffer time of 133sec. To be on the safe side, I opted for a margin of ~30%, and use the shortest possible buffer time (99sec). ------------------------------------------------------------------------------------------------------------------------------------ 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-394 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A GD-394 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G 13719( 9) - 14-May-2015 16:26:58 - [ 9] Visit: 06 Visit Requirements: Period 1.150 D AND ZERO-PHASE HJD2450004.818 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 GD-394 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.1 S (0.1 PHASE 0.625 TO 0.655; GS S) ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 GD-394 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=99 1 2595 S -MAMA G (2595 S) Comments: The ETC simulation STIS.sp.622199 gives a "Count rate entire detector" of 14300 cts/s, i.e. a buffer time of 133sec. To be on the safe side, I opted for a margin of ~30%, and use the shortest possible buffer time (99sec). ------------------------------------------------------------------------------------------------------------------------------------ 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-394 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A GD-394 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G 13719( 9) - 14-May-2015 16:26:58 - [ 10] Visit: 07 Visit Requirements: Period 1.150 D AND ZERO-PHASE HJD2450004.818 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 GD-394 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.1 S (0.1 PHASE 0.75 TO 0.78; GS S) ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 GD-394 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=99 1 2595 S -MAMA G (2595 S) Comments: The ETC simulation STIS.sp.622199 gives a "Count rate entire detector" of 14300 cts/s, i.e. a buffer time of 133sec. To be on the safe side, I opted for a margin of ~30%, and use the shortest possible buffer time (99sec). ------------------------------------------------------------------------------------------------------------------------------------ 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-394 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A GD-394 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G 13719( 9) - 14-May-2015 16:26:58 - [ 11] Visit: 08 Visit Requirements: Period 1.150 D AND ZERO-PHASE HJD2450004.818 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 GD-394 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.1 S (0.1 PHASE 0.875 TO 0.905; GS S) ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 GD-394 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=99 1 2595 S -MAMA G (2595 S) Comments: The ETC simulation STIS.sp.622199 gives a "Count rate entire detector" of 14300 cts/s, i.e. a buffer time of 133sec. To be on the safe side, I opted for a margin of ~30%, and use the shortest possible buffer time (99sec). ------------------------------------------------------------------------------------------------------------------------------------ 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-394 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A GD-394 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G 13719( 9) - 14-May-2015 16:26:58 - [ 12] Summary Form for Proposal 13719 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.2X0.2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT, BUFFER-TIME=99 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GROUP 01, 02, 03, 04, 05, 06, 07, 08 WITHIN 5D, GS ACQ SCENARIO BASE1B3, PHASE 0.0 TO 0.03, PHASE 0.125 TO 0.155, PHASE 0.25 TO 0.28, PHASE 0.375 TO 0.405, PHASE 0.5 TO 0.53, PHASE 0.625 TO 0.655, PHASE 0.75 TO 0.78, PHASE 0.875 TO 0.905, Period 1.150 D AND ZERO-PHASE HJD2450004.818 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements E140M, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names GD-394 ------------------------------------------------------------------------------------------------------------------------------------