13700( 2) - 11-Jul-2014 12:45:24 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13700 Version: 2 Check-in Time: 11-Jul-2014 12:45:24 STScI Edit Number: 0 Title Confirming the most water-rich extrasolar rocky body ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Carl Melis University of California - San Diego Y CoI: Dr. Patrick Dufour Universite de Montreal N ------------------------------------------------------------------------------------ Abstract Most theories of exobiology require liquid water for a planet to be considered as habitable. Yet, very little is known about the prevalence of water for mature rocky objects in extrasolar planetary systems. A unique method of probing the existence, characteristics, and frequency of extrasolar water-bearing rocky bodies is through examining their bulk composition after they have been accreted by their host white dwarf star. Results to date show that water-rich extrasolar rocky bodies are rare. Evidence for oxygen in ground-based spectroscopy of SDSSJ104341.53+085558.2 suggests that it could be accreting the most water-rich extrasolar rocky object currently known. We propose COS ultraviolet spectroscopy to confirm the water-rich nature and characterize the mineralogy of the rocky body being accreted by this white dwarf star. ------------------------------------------------------------------------------------ Observations Description ------------------------ Detecting or constraining the absorption lines which inform our science goals requires observations in the 1130-1433 Ang range. Medium spectral resolution ultraviolet spectroscopy with COS and the G130M grating and a central wavelength of 1291 Ang will satisfy the observational requirements. ALL FP-POS positions will be used to mitigate fixed pattern noise. For the GALEX measured FUV flux of SDSS J1043 (FUV AB magnitude of 16.91+/-0.05) it should be possible to obtain average S/N~15 in the 1130-1433 Ang wavelength range with a total on-source exposure time of ~4, 000 seconds. Signal-to-noise ratio of ~15 for the 1130- 1433 Ang wavelength range will enable detection or tight limits on the abundances of oxygen, iron, carbon, and aluminum (the main science goals). Such a signal-to-noise ratio will also enable the detection or constraint of other elements (e.g., nitrogen, sulfur, or phosphorus). These estimates are made using the COS ETC assuming standard background parameters and with a white dwarf spectral energy distribution matched to the parameters and flux level of SDSS J1043 (reddened by E_B-V=0.03 to match the GALEX data points). 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, our request adds up to 2 orbits for COS observations of SDSS J1043. 13700( 2) - 11-Jul-2014 12:45:24 - [ 2] Observations will be done in the TIME-TAG mode using TAG-FLASH wavelength calibration. SDSS J1043 is an ICRS object (SDSS position with less than 0.4" positional uncertainty), has measured GALEX FUV and NUV fluxes, and is safe for the COS detectors in our desired setups. ------------------------------------------------------------------------------------ 13700( 2) - 11-Jul-2014 12:45:24 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 WD-1041+092 STAR, POST-AGB STAR RA=10H43M41.5490S +/- 0.05", J2000 V = 17.12 +/- 0.02 GALEX DEC=+08D55'58.08" +/- 0.05" FUV=16.91+/-0.05 AB magnitudes, GALEX NUV=17.12+/-0.03 AB magnitudes Reference Frame: ICRS Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2006.3933 0.002564437038479162 -0.046 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 13700( 2) - 11-Jul-2014 12:45:24 - [ 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 WD-1041+092 COS/NUV ACQ/IMA PSA MIRRORB 1 45 S (45 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 WD-1041+092 COS/FUV TIME-TA PSA G130M 1291 FP-POS=ALL, BUFFER-TIME=2520, 1 1000 S G FLASH=YES see below (5104 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 | ------------------------------------------------------------------------------------------------------------------------------------ WD-1041+092 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE WD-1041+092 2 COS/FUV TIME-TA PSA G130M 1291 none none none 1 1 1156.0 S G WD-1041+092 2 COS/FUV TIME-TA PSA G130M 1291 none none none 2 1 1156.0 S G WD-1041+092 2 COS/FUV TIME-TA PSA G130M 1291 none none none 3 2 1396.0 S G WD-1041+092 2 COS/FUV TIME-TA PSA G130M 1291 none none none 4 2 1396.0 S G 13700( 2) - 11-Jul-2014 12:45:24 - [ 5] Summary Form for Proposal 13700 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=2520, FLASH=YES, FP-POS=ALL ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names WD-1041+092 ------------------------------------------------------------------------------------------------------------------------------------