Proposal_Information ! Section 4 Title: THE WIND AND PHOTOSPHERE OF THE UNIQUE DO WHITE DWARF RE\ J0503-289 Proposal_Category: GO Scientific_Category: HOT STARS Cycle: 6 Investigators PI_name: Dr. Martin Barstow PI_Institution: University of Leicester CoI_Name: Dr. Jay Holberg CoI_Institution: University of Arizona Contact: ! N (designate at most one contact) CoI_Name: Dr. Edward Sion CoI_Institution: Villanova University Contact: ! Y (designate at most one contact) CoI_Name: Dr. Ivan Hubeny CoI_Institution: Goddard Space Flight Center Contact: ! N (designate at most one contact) CoI_Name: Dr. Thierry Lanz CoI_Institution: Goddard Space Flight Center Contact: ! N (designate at most one contact) Abstract: ! Free format text (please update) We propose to obtain high S/N GHRS spectra of the key He-rich white dwarf RE J0503-289. These observations have two principal aims. The first is to investigate the phenomenon of mass loss in this star. Excluding planetary nebulae nuclei, RE J0503-289 is the only white dwarf in which evidence of ongoing mass loss has been observed with IUE. However, the reported detection is near the limit of the sensitivity of IUE preventing study of the wind during its less intense periods. Mass loss may well be the missing ingredient in the theoretical description of heavy element abundances in white dwarfs. RE J0503-289 is the only known white dwarf where this effect can be studied as an on going phenomenon. The second aim is to search for Fe and Ni in the photosphere of this star. The presence of these elements is required to explain the large flux deficit observed in the EUV. Detailed models, including those elements so far detected (C, N, O and Si), substantially over predict EUV flux levels. RE J0503-289 is also the only DO white dwarf for which a joint analysis of EUV and UV data will be possible and for which we can conduct a definitive study of the composition and structure of the photosphere. Questions ! Free format text (please update) Observing_Description: The proposed GHRS observations for RE J0503-289 are given below. The spectral coverage, spectral configuration, signal- to-noise, exposure time and ions expected to be seen are given for each spectral setup. All spectra will be obtained using the standard FP-SPLIT=4 option. This is to minimize the effects of fixed pattern detector noise and to easily identify any diode dropouts, which could produce artificial absorption features. The required S/N of 20 corresponds to ~ 400 counts per data point, where each diode is quarter stepped (each diode is used 4 times in a comb addition to produce the spectrum). This represents STEP-PATTERN=5 for the G160M grating.In all we need exposures for each of two wavelength ranges. beginitemize em 1235-1270Angstrom : exposure (S/N=20) = \ 7 min: NV + FeV/FeVI/NiV/NiVI em 1370- 1405Angstrom : exposure (S/N=20) = 10 min: OV/SiIV + FeV/FeVI/NiV/NiVI enditemize . In addition we will obtain a 21 minute exposure of HeII to allow a detailed cross reference of the HST data with that already obtained for IUE. The above exposures are combined into one visit of two orbits. With a visibility of 53min per orbit, three exposures in NV and OV ranges are possible, after accounting for observation overheads. Hence the total time coverage will be about 150min. Real_Time_Justification: None None Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: REJ0503-289 Alternate_Names: Description: STAR,WDO Position: RA=05H 03M 55.39S +/- 0.2S, DEC=-28D 54' 36.4" +/- 0.25", PLATE-ID=04WB Equinox: J2000 RV_or_Z: RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: B1978.77 Annual_Parallax: Flux: ! Include at least V and B-V V = 13.90 +/- 0.01 B-V = -0.35 +/- 0.01 F-CONT(1400) = 1.2 +/- 0.1E-12 Comments: Solar_System_Targets ! Section 5.2 Generic_Targets ! Section 5.3 Scan_Data ! Appendix B ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 01 Visit_Requirements: ! Section 7.1 On_Hold_Comments: Visit_Comments: Exposure_Number: 1 ! Section 6.5 Target_Name: REJ0503-289 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 1.8s Special_Requirements: ONBOARD ACQ FOR 11-17 Comments: expected count rate = 22,500 c/s Exposure_Number: 11 ! Section 6.5 Target_Name: REJ0503-289 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1370-1405 Optional_Parameters: COMB=FOUR,STEP-PATT=5,FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 652.8s Special_Requirements: ! Section 7.2 Comments: Exposure_Number: 12 ! Section 6.5 Target_Name: WAVE Config: HRS Opmode: ACCUM Aperture: SC2 Sp_Element: G160M Wavelength: 1235-1270 Optional_Parameters: SPYBAL=YES Number_of_Iterations: 1 Time_Per_Exposure: 54.4s Special_Requirements: ! Section 7.2 Comments: WAVECAL for 1235-1270 region Exposure_Number: 13 ! Section 6.5 Target_Name: REJ0503-289 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1235-1270 Optional_Parameters: COMB=FOUR,STEP-PATT=5,FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 435.2s Special_Requirements: ! Section 7.2 Comments: Exposure_Number: 14 ! Section 6.5 Target_Name: REJ0503-289 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1370-1405 Optional_Parameters: COMB=FOUR,STEP-PATT=5,FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 544s Special_Requirements: ! Section 7.2 Comments: Exposure_Number: 15 ! Section 6.5 Target_Name: REJ0503-289 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1620-1655 Optional_Parameters: COMB=FOUR,STEP-PATT=5,FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 979.2s Special_Requirements: ! Section 7.2 Comments: Exposure_Number: 16 ! Section 6.5 Target_Name: REJ0503-289 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1370-1405 Optional_Parameters: COMB=FOUR,STEP-PATT=5,FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 544s Special_Requirements: ! Section 7.2 Comments: Exposure_Number: 17 ! Section 6.5 Target_Name: REJ0503-289 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1235-1270 Optional_Parameters: COMB=FOUR,STEP-PATT=5,FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 435.2s Special_Requirements: ! Section 7.2 Comments: Data_Distribution ! Defaults indicated; change if desired Medium: 8MM ! 8MM or 6250BPI or 1600BPI Blocking_Factor: 10 ! 10 or 1 ! Only astronomers with very old 9- ! track tape drives should consider ! a blocking factor of 1 Ship_To: PI_Address ! STSCI or PI_Address or ! PI Address from Phase I is: ! ! Department of Physics and Astro ! nomy ! University Road ! Leicester ! LE1 7RH ! ! Ship_Via: UPS ! UPS (2-day) or OVERNIGHT ! 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