14691( 2) - 12-Jul-2016 20:35:02 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14691 Version: 2 Check-in Time: 12-Jul-2016 20:35:02 STScI Edit Number: 1 Title Unraveling the oscillations of the richest pulsating hydrogen-atmosphere white dwarf ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. JJ Hermes University of North Carolina at Chapel Y Hill CoI: Dr. James Christopher Clemens University of North Carolina at Chapel N Hill CoI: Bart Dunlap University of North Carolina at Chapel N Hill CoI: Prof. Boris T. Gaensicke The University of Warwick N CoI: Prof. Detlev G. Koester Universitat Kiel N CoI: Dr. Steven D. Kawaler Iowa State University N CoI: Dr. Michael Montgomery University of Texas at Austin N CoI: Dr. Donald E. Winget University of Texas at Austin N ------------------------------------------------------------------------------------ Abstract Most stars in our Galaxy will end or have already ended their lives as white dwarf stars, making them important benchmarks for stellar evolution. Here we propose to obtain COS far-ultraviolet spectroscopy of a pulsating hydrogen-atmosphere white dwarf (DAV) with extensive, space-based photometry obtained by the Kepler spacecraft during the K2 mission. The pulsation spectrum is the richest of any DAV collected to date, but to extract any information about the white dwarf interior we must identify the spherical degree (l) of the modes present. Our time-tagged ultraviolet observations will enable us to identify the spherical degree of the highest-amplitude pulsation modes, since the ratios of the ultraviolet-to-optical pulsation amplitudes strongly depend on the geometry of the pulsation modes. This will decisively determine if most of the modes present are a series of l=3 modes, as it appears from the frequency multiplets in the K2 data; however, l=3 modes have never been clearly identified in a pulsating white dwarf. Our far-ultraviolet spectroscopy, covering the H2/H2+ quasi-molecular satellites around 1400 and 1600 AA, will also measure the white dwarf temperature and mass to an accuracy unachievable from the ground. This robust temperature and mass will anchor our detailed asteroseismic investigation of this stellar remnant. The unique combination of HST and Kepler observations will make this white dwarf a benchmark for the unprecedented opportunities for white dwarf archaeology enabled by the original Kepler mission and its extension into the ecliptic, K2. ------------------------------------------------------------------------------------ Observations Description ------------------------ The two main goals of our observations are to measure the atmospheric parameters of this pulsating white dwarf and to measure the far-UV pulsation amplitudes. Using the COS G140L grating centered at 1105 AA, we cover the appropriate spectral features at sufficient spectral resolution to accurately determine the atmospheric parameters. The time-series photometry from the 14691( 2) - 12-Jul-2016 20:35:02 - [ 2] time-tagged data will require slightly more planning. In summary, we request our two three-orbit visits to be separated by 2.2 days (up to no more than 6.0 days separating the visits) in order to fully resolve the pulsations, which in the nearest case are separated by as little as 5.5 microHz. Further information and justification is found in the Description of the Observations section of the accepted proposal. ------------------------------------------------------------------------------------ 14691( 2) - 12-Jul-2016 20:35:02 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSS-J084055 STAR, ZZ CETI STAR RA=08H40M55.7210S +/- 0.1", J2000 V = 17.16 +/- 0.20 g=17.12 .72+130329.5 DEC=+13D03'29.50" +/- 0.1" Reference Frame: ICRS Extended: NO Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 7.527999241641008E-4 -0.0099 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 14691( 2) - 12-Jul-2016 20:35:02 - [ 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 SDSS-J08405 COS/NUV ACQ/IMA PSA MIRRORA 1 5 S (5 S) 5.72+130329 GE .5 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSS-J08405 COS/FUV TIME-TA PSA G140L 1105 FP-POS=1, BUFFER-TIME=2549 1 2549 S 5.72+130329 G (2549 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSS-J08405 COS/FUV TIME-TA PSA G140L 1105 FP-POS=2, BUFFER-TIME=2932 1 2932 S 5.72+130329 G (2932 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 4 SDSS-J08405 COS/FUV TIME-TA PSA G140L 1105 FP-POS=3, BUFFER-TIME=2932 1 2932 S 5.72+130329 G (2932 S) .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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSS-J084055.72+130 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 329.5 GE SDSS-J084055.72+130 2 COS/FUV TIME-TA PSA G140L 1105 none none none none 1 N/A 329.5 G SDSS-J084055.72+130 3 COS/FUV TIME-TA PSA G140L 1105 none none none none 2 N/A 329.5 G SDSS-J084055.72+130 4 COS/FUV TIME-TA PSA G140L 1105 none none none none 3 N/A 329.5 G 14691( 2) - 12-Jul-2016 20:35:02 - [ 5] Visit: 02 Visit Requirements: AFTER 01 BY 2.2 D TO 6.0 D 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 SDSS-J08405 COS/NUV ACQ/IMA PSA MIRRORA 1 5 S (5 S) 5.72+130329 GE .5 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSS-J08405 COS/FUV TIME-TA PSA G140L 1105 FP-POS=1, BUFFER-TIME=2549 1 2549 S 5.72+130329 G (2549 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSS-J08405 COS/FUV TIME-TA PSA G140L 1105 FP-POS=2, BUFFER-TIME=2932 1 2932 S 5.72+130329 G (2932 S) .5 ------------------------------------------------------------------------------------------------------------------------------------ 4 SDSS-J08405 COS/FUV TIME-TA PSA G140L 1105 FP-POS=3, BUFFER-TIME=2932 1 2932 S 5.72+130329 G (2932 S) .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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSS-J084055.72+130 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 329.5 GE SDSS-J084055.72+130 2 COS/FUV TIME-TA PSA G140L 1105 none none none none 1 N/A 329.5 G SDSS-J084055.72+130 3 COS/FUV TIME-TA PSA G140L 1105 none none none none 2 N/A 329.5 G SDSS-J084055.72+130 4 COS/FUV TIME-TA PSA G140L 1105 none none none none 3 N/A 329.5 G 14691( 2) - 12-Jul-2016 20:35:02 - [ 6] Summary Form for Proposal 14691 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=2549, BUFFER-TIME=2932, FP-POS=1, FP-POS=2, FP-POS=3 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 2.2 D TO 6.0 D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names SDSS-J084055.72+130329.5 ------------------------------------------------------------------------------------------------------------------------------------