13358( 2) - 04-Jun-2013 15:09:07 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13358 Version: 2 Check-in Time: 04-Jun-2013 15:09:07 STScI Edit Number: 0 Title Trans-iron group elements in the hot white dwarf RE 0503-289 ------------------------------------------------------------------------------------ Type Cycle GO 21 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Klaus Werner Eberhard Karls Universitat, Tubingen Y CoI: Dr. Thomas Rauch Eberhard Karls Universitat, Tubingen N ------------------------------------------------------------------------------------ Abstract We propose STIS-UV spectroscopy of the rather peculiar, hot helium-rich white dwarf RE 0503-289. In FUSE spectra we have recently discovered as much as ten trans-iron group elements (atomic numbers between 31-54), a phenomenon that has never been observed before in any WD. Abundance analyses of Kr, Xe, and Ge show that they are strongly overabundant (450 to 3800 times solar). We suspect that this is related to the evolutionary history of the WD. RE 0503-289 is a transition object between the PG1159 and DO spectral classes, which represent a (pre-) WD sequence of stars that suffered a late He-shell flash. As a consequence of flash-induced envelope convection, the WD exposes the H-He intershell layer of the progenitor AGB star that is enriched with trans-Fe elements resulting from s-process nucleosynthesis. The proposed UV observations shall support a precise abundance analysis of all other elements detected so far, but we mainly aim at the detection and analysis of hitherto undetected heavy elements. We want to address the question whether the observed abundance pattern is affected by diffusion or if it represents the original composition of the s-processed material. In the latter case, detailed tests of nucleosynthesis models are possible. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will perform short-slit (0.2"x0.2") medium-dispersion UV spectroscopy of RE0503-289 in the STIS/FUV-MAMA and NUV-MAMA configurations with gratings E140M and E230M (two wavelength settings), respectively, in order to cover the wavelength range 1150-3100 A. This provides the spectral resolution (~30, 000) needed for the quantitative analysis of narrow metal lines. STIS ETC was used to estimate exposure times necessary to achieve the required S/N ~ 20-40. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- 13358( 2) - 04-Jun-2013 15:09:07 - [ 2] ------------------------------------------------------------------------------------ 13358( 2) - 04-Jun-2013 15:09:07 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 RE0503-289 STAR, WDO RA=05H03M55.5130S, J2000 V = 13.9 +/- 0.1 1.8E-12 erg/(cm2 s A) DEC=-28D54'34.57" at 1360 A Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 13358( 2) - 04-Jun-2013 15:09:07 - [ 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 RE0503-289 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 1.0 S (1 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RE0503-289 STIS/FUV ACCUM 0.2X0.2 E140M 1425 1 2493 S -MAMA (2493 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 RE0503-289 STIS/FUV ACCUM 0.2X0.2 E140M 1425 1 3001 S -MAMA (3001 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 RE0503-289 STIS/NUV ACCUM 0.2X0.2 E230M 1978 1 1338 S -MAMA (1338 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 RE0503-289 STIS/NUV ACCUM 0.2X0.2 E230M 2707 1 1338 S -MAMA (1338 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 | ------------------------------------------------------------------------------------------------------------------------------------ RE0503-289 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A RE0503-289 2 STIS/FUV ACCUM 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA RE0503-289 3 STIS/FUV ACCUM 0.2X0.2 E140M 1425 none none none none 2 N/A -MAMA RE0503-289 4 STIS/NUV ACCUM 0.2X0.2 E230M 1978 none none none none 3 N/A -MAMA RE0503-289 5 STIS/NUV ACCUM 0.2X0.2 E230M 2707 none none none none 3 N/A -MAMA 13358( 2) - 04-Jun-2013 15:09:07 - [ 5] Summary Form for Proposal 13358 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.2X0.2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements E140M, E230M, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names RE0503-289 ------------------------------------------------------------------------------------------------------------------------------------