! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6456,v 8.1 1996/06/28 14:27:22 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Karla Peterson ! Phone: 410-338-4774 , E-mail: peterson@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. Proposal_Information ! Section 4 Title: The photospheric iron abundance of UV bright stars in globular clusters Proposal_Category: GO Scientific_Category: STELLAR POPULATIONS Cycle: 6 Investigators PI_name: Ralf Napiwotzki PI_Institution: Universitaet Erlangen-Nuernberg CoI_Name: Ulrich Heber CoI_Institution: Universitaet Erlangen-Nuernberg Contact: ! Y or N (designate at most one contact) CoI_Name: Stefan Haas CoI_Institution: Universitaet Erlangen-Nuernberg Contact: ! Y or N (designate at most one contact) CoI_Name: Sabine Moehler CoI_Institution: Landesternwarte Heidelberg Contact: ! Y or N (designate at most one contact) CoI_Name: Stefan Dreizler CoI_Institution: Universitaet Kiel Contact: ! Y or N (designate at most one contact) CoI_Name: Klaus Werner CoI_Institution: Universitaet Potsdam Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) UV bright stars can be found in colour-magnitude diagrams of globular clusters, lying above the horizontal branch and to the blue of the giant branch. They are mostly post-AGB stars evolving to white dwarfs. Recent analyses of field pop. II post-AGB stars raised the question if the chemical abundances in their atmospheres are the product of dredge-ups or of a gas -dust-separation. The knowledge of the original metallicities (= metallicity of the globular cluster) of the cluster post- AGB stars will allow to overcome this ambiguity. From the measurement of the iron abundance in these stars it can directly be judged if dust depletion is at work. Existing high -S/N, high resolution optical spectra allow the abundances of lighter elements (C,N,O,Si) to be measured, but no iron lines are present. In the UV, however, lines of iron (Fe III, Fe IV and Fe V) can be used. Highly sophisticated NLTE model atmospheres and accurate atomic data are at hand in order to determine precise iron abundances. Thus a crucial test of the predictions of stellar evolutionary theory for low-mass stars can be performed. We therefore propose high-resolution spectroscopic observations of iron lines (in carefully selected wavelengths regions) in the UV for five post-AGB stars spread out over a large range in T(eff) (20000 K\ldots51000 K). Parallel observations with WFPC2 in the outer regions of the clusters shall collect images in FUV (1600Angstrom), U and V to search for faint blue stars. Questions ! Free format text (please update) Observing_Description: We propose observations of two hot UV bright stars (ROA5701 and Barnard 29) with the GHRS with grating G200M in the wavelength range 1865\ldots 1905 Angstrom\ and a three additional targets (vZ 1128, PG 2120+062, ROB 162) with grating G160M and central wavelength 1615 Angstrom\ and 1280 Angstrom\ (ROB 162), respectively. We aim at a signal-to- noise ratio of ~30. From our experience with the analysis of coadded IUE high resolution spectra of the pop. II central star BD+33 2642 this S/N is adequate for a model atmosphere analysis of the iron lines even at the low abundances expected. From the known temperature and magnitudes (and reddening) of the target objects we calculate fluxes and count rates (0.13, 0.14, 0.19, 0.6 and 0.17 counts/s/diode for ROA 5701, vZ 1128, and Barnard 29, ROB 162 and PG 2120+062, resp.). Including overhead times the exposure time available in two orbits will yield S/N in the range 25\ldots 30 for the target stars, except for ROB 162 which requires only one orbit. The cluster target stars lie typically about 2 arcmin. from the cluster center. Coordinates have been taken from literature (ROA 5701, Barnard 29, vZ1128, including the earliest papers by von Zeippel, 1908 and Barnard, 1931) or measured recently by Dr. A. Good at ROE (ROB 162). Since they are the UV brightest stars in the clusters and do not lie in the very centers of the cluster, the ``Return to brightest Point'' mode of GHRS will allow a safe target acquisition into the LSA. Parallel exposures As explained in the scientific justification, we plan to take WFPC2 images in U,V and UV (F160BW or F170W) filters in parallel mode to search for faint blue stars. These observations can be taken while exposing the primary targets at no extra cost, and will allow us to construct deep colour- magnitude and colour-colour diagrams. We propose to obtain a combination of short and long exposures in order to recover, without saturation, stars in a wide magnitude range. We plan to use the F606W filter as V filter as it is much more efficient than F555W and can be transformed to Johnson V. ! Real_Time_Justification: ! ! Supporting optical spectroscopy with KECK-HIRES is planned ! for spring 1996 (in collaboration with Dr. N. Reid, Caltech) ! to improve the already existing optical data (both in S/N and ! in wavelength coverage). !Calibration_Justification: ! Move appropriate text from Real_Time_Justification ! ! Additional_Comments: ! ! Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: NGC5139-132729-472247 Alternate_Names: NGC5139-ROA5701 Description: STAR,SDO Position: RA=13H 27M 28.89S +/- 0.02S, ! Most common specification format is DEC=-47D 22' 48.1" +/- 0.3", ! RA=0H 0M 0.00S +/- 0S, PLATE-ID=00AK Equinox: J2000 Epoch: Comments: Flux: V=13.2 +/- 0.2, F(1900) = 2.1 +/- 0.2 E-13 ! Include at least V and B-V Target_Number: 2 Target_Name: NGC6205-164133+362852 Alternate_Names: NGC6205-BARNARD29,NGC6205-Lu222 Description: STAR,SDO Position: RA=16H 41M 33.74S +/- 0.03S, ! Most common specification format is DEC=+36D 26' 07.8" +/- 0.3", ! RA=0H 0M 0.00S +/- 0S, PLATE-ID=00CK Equinox: J2000 Epoch: Comments: Flux: V=13.0 +/- 0.1, F(1900) = 2.8 +/- 0.2 E-13 ! Include at least V and B-V Target_Number: 3 Target_Name: NGC5272-133740+282601 Alternate_Names: NGC5272-VZ1128,GSC2004-1057 Description: STAR,SDO Position: RA=13H 42M 16.75S +/- 0.02S, DEC=+28D 26' 01.1" +/- 0.2", PLATE-ID=009L Equinox: J2000 Epoch: Comments: Coordinates from GSC Flux: V=14.9, ! Include at least V and B-V F(1600) = 1.7 +/- 0.1 e-13 Target_Number: 4 Target_Name: NGC6397-174038-533832 Alternate_Names: NGC6397-ROB162,GSC8729-1093 Description: STAR,SDO Position: RA=17H 40M 38.35S +/- 0.02S, ! Most common specification format is DEC=-53D 38' 31.6" +/- 0.3", ! RA=0H 0M 0.00S +/- 0S, PLATE-ID=0688 ! DEC=0D 0' 0.0" +/- 0", Equinox: J2000 Epoch: Comments: Coordinates from GSC Flux: V=13.2, ! Include at least V and B-V F(1300) = 8.0 +/- 0.5 e-13 Target_Number: 5 Target_Name: STAR-212003+060903 Alternate_Names: PG2120+062,GSC541-1367 Description: STAR,SDO Position: RA=21H 22M 31.73S +/- 0.02S, ! Most common specification format is DEC=+06D 21' 56.1" +/- 0.2", ! RA=0H 0M 0.00S +/- 0S, PLATE-ID=02V8 ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: J2000 Epoch: Comments: Coordinates from GSC Flux: V=14.4 +/-0.1, ! Include at least V and B-V F(1600) = 2.15 +/- 0.2 e-13 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Visits ! Section 6 Visit_Number: 1 Visit_Requirements: ! Section 7.1 On_Hold_Comments: Visit_Comments: Exposure_Number: 1 ! Section 6.5 Target_Name: NGC5139-132729-472247 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 1.8S Special_Requirements: ONBOARD ACQ FOR 2 ! Section 7.2 Comments: STEP-TIME=0.2S, EXPECT 2500 CNTS Exposure_Number: 2 ! Section 6.5 Target_Name: NGC5139-132729-472247 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G200M Wavelength: 1865-1905 Optional_Parameters: Number_of_Iterations: 8 Time_Per_Exposure: 598.4S Special_Requirements: ! Section 7.2 Comments: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Visit_Number: 2 Visit_Requirements: ! Section 7.1 On_Hold_Comments: Visit_Comments: Exposure_Number: 1 ! Section 6.5 Target_Name: NGC6205-164133+362852 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 1.8S Special_Requirements: ONBOARD ACQ FOR 2 ! Section 7.2 Comments: STEP-TIME=0.2S, EXPECT 3500 CNTS Exposure_Number: 2 ! Section 6.5 Target_Name: NGC6205-164133+362852 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G200M Wavelength: 1865-1905 Optional_Parameters: Number_of_Iterations: 8 Time_Per_Exposure: 584.8S Special_Requirements: ! Section 7.2 Comments: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Visit_Number: 3 Visit_Requirements: ! Section 7.1 On_Hold_Comments: Visit_Comments: Exposure_Number: 1 ! Section 6.5 Target_Name: NGC5272-133740+282601 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 3.6S Special_Requirements: ONBOARD ACQ FOR 2 ! Section 7.2 Comments: STEP-TIME=0.4S, EXPECT 2500 CNTS Exposure_Number: 2 ! Section 6.5 Target_Name: NGC5272-133740+282601 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1600-1635 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 4 Time_Per_Exposure: 1088.0S Special_Requirements: ! Section 7.2 Comments: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Visit_Number: 4 Visit_Requirements: ! Section 7.1 On_Hold_Comments: Visit_Comments: Exposure_Number: 1 ! Section 6.5 Target_Name: NGC6397-174038-533832 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 1.8S Special_Requirements: ONBOARD ACQ FOR 2 ! Section 7.2 Comments: STEP-TIME=0.2S, EXPECT 3500 CNTS Exposure_Number: 2 ! Section 6.5 Target_Name: NGC6397-174038-533832 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1255-1290 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 2 Time_Per_Exposure: 870.4S Special_Requirements: ! Section 7.2 Comments: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Visit_Number: 5 Visit_Requirements: ! Section 7.1 On_Hold_Comments: Visit_Comments: Exposure_Number: 1 ! Section 6.5 Target_Name: STAR-212003+060903 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 2.7S Special_Requirements: ONBOARD ACQ FOR 2 ! Section 7.2 Comments: STEP-TIME=0.3S, EXPECT 2000 CNTS Exposure_Number: 2 ! Section 6.5 Target_Name: STAR-212003+060903 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1600-1635 Optional_Parameters: Number_of_Iterations: 8 Time_Per_Exposure: 571.2S Special_Requirements: ! Section 7.2 Comments: Data_Distribution Medium: 8MM Blocking_Factor: 10 Ship_To: PI_Address Ship_Via: UPS Recipient_Email: