! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 5866,v 5.1 1995/06/12 14:39:46 pepsa Exp $ ! ! Subject: pg1159 stars proposal #5866 Vers March 10 17:00 CET ! ! For help call your Program Coordinator: Karla Peterson ! Phone: 410 338-4774, E-mail: peterson@stsci.edu ! !! This partially completed template was generated from your Phase I proposal. ! ! This is the Phase II version now Proposal_Information ! Section 4 Title: NLTE spectral analysis of PG1159 stars: Finding the limits of the GW Vir instability strip Proposal_Category: GO Scientific_Category: Hot Stars Cycle: 5 Investigators PI_name: Ulrich Heber PI_Institution: Astronomisches Institut der Universitaet Erlangen-Nuernberg CoI_Name: Stefan Dreizler CoI_Institution: Astronomisches Institut der Universitaet Erlangen-Nuernberg Contact: N ! Y or N (designate at most one contact) CoI_Name: Klaus Werner CoI_Institution: Institut fuer Theoretische Physik u. Sternwarte der Universitaet Kiel Contact: N ! Y or N (designate at most one contact) CoI_Name: Thomas Rauch CoI_Institution: Institut fuer Theoretische Physik u. Sternwarte der Universitaet Kiel Contact: N ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) The PG1159 stars form a new class of hydrogen deficient pre white dwarfs (PWD) representing the hottest stage of PWD evolution. Quan\-titative spectral analyses of all known PG1159 stars have been carried out by the proposers from optical, UV (IUE + HST-FOS) and EUV (EUVE) observations. It has been shown that these stars have atmospheres dominated by C and He. In the hottest stars also a significant amount of O is present. About every other member of the PG1159 stars is a non-radial, multi-periodic g-mode pulsator driven by cyclic ionization of C and O. Modelling of the pulsations allows the stellar mass to be determined very accurately and the stellar interior to be probed (asteroseismology). A prerequisite for such modelling is a precise determination of the photospheric parameters. We propose to obtain UV observations of 8 PG1159 stars (4 pulsators and 4 non-pulsators) in order to trace differences in photospheric parameters and composition (especially O). The spectra will be analysed with new highly sophisticated NLTE line blanketed model atmospheres, which allow the synthetic spectrum to be calculated and line blending of iron group elements to be included self\- consistently. The results will allow us to determine the position of the new instability strip (defined by the pulsating PG1159 stars) in the HRD. This is an updated version of cycle3 proposal 4263 which was awarded 9.48 hours FOS observing time (medium priority) but no observations were carried out. Questions ! Free format text (please update) Observing_Description: Therefore we propose the following observations: , i) The ionOV 1371Angstrom\ line together with UV-ionOIV lines (1340Angstrom) are the only means to determine the O abundance and will reduce the uncertainties in T(eff) considerably. Fig.15 in WHH predicts an extreme temperature sensitivity of the ionOV line. It follows that the determination of T(eff) with a precision of 1\ can be measured to an accuracy of about 10\ ii) The ionNV, 1240Angstrom\ resonance line is the only means to determine the nitrogen abundance (no other N lines are detectable). Many other lines of CIV and OVI can be identified in the UV (see WHH) and will allow to determine abundances with unprecedented precision. Because of the high gravity, all spectral features are relatively broad and shallow. Hence a spectral resolution of about 1Angstrom\ is sufficient, which can be reached with the low dispersion GHRS grating (G140L) and the large science aperture. A high S/N ratio is necessary, however, in order to perform detailed line profile fits (S/N=60 to 90 is aimed at). IUE low resolution spectra exist of all targets, but they are too noisy and of too low resolution for a quantitative analysis. The resulting atmospheric parameters and abundances will constrain the position of the GW Vir instability strip in the HRD, probably as a function of the stellar surface abundances, especially of the O abundance. Exposure times and S/N have been calculated from available IUE fluxes, visibility periods, overhead times and the sensitivities given in the handbook. One visit is necessary for each star and we propose to observe each target for one orbit. An example: PG1707+427 is visible for 54 min. during one orbit; subtracting the overhead time for guide star and target acquisition as well as the instrument overhead (12 + 11 + 4 = 27 min.) 27 minutes of exposure time remain. PG1707+427 has a measured flux at 1350Angstrom\ of 1.5* 10^-13 erg/cm/cm/s/Angstrom. With a sensitivity of the G140L grating of S=166times10^11 S/N=64 is calculated from the equation on page 29 of the handbook. One target (HS0704+6153) lies in the continuous viewing zone and, hence, can be observed for 96 min. several times in the year. Since it is also the faintest of our programme stars, the S/N will benefit from the longer exposure time for HS0704. Two other targets (PG1424+535 and HS1517+7403) lie marginally in the CVZ. However the possibility to observe them during the entire orbit occurs only once or twice per year. Moreover, the stars are relatively bright, so that S/N~100 is reached within ~ 30 min. and the CVZ opportunity is not essential for these two stars. Fixed_Targets Target_Number: 1 Target_Name: STAR-1520+525 Alternate_Names: PG1520+525 Description: STAR,PG1159 STAR Position: RA=15H 21M 46.542S +/- 0.013S, DEC=+52D 22' 3.85" +/- 0.2", PLATE-ID=01RT Equinox: J2000 Epoch: Flux: V = 15.5 +/- 0.2, B-V=-0.3 +/-0.1 Comments: Coordinates have been measured by GASP in cycle 3 Target_Number: 2 Target_Name: STAR-1424+535 Alternate_Names: PG1424+535 Description: STAR,PG1159 STAR Position: RA=14H 25M 55.412S +/- 0.013S, DEC=+53D 15' 24.76" +/- 0.2", PLATE-ID=01AL Equinox: J2000 Epoch: Flux: V = 16.2 +/- 0.2, B-V=-0.3 +/-0.1 Comments: Coordinates have been measured by GASP in cycle 3 Target_Number: 3 Target_Name: STAR-1707+427 Alternate_Names: PG1707+427 Description: STAR,PG1159 STAR,PULSATING VARIABLE Position: RA=17H 8M 47.697S +/- 0.013S, DEC=+42D 40' 59.95" +/- 0.2", PLATE-ID=009J Equinox: J2000 Epoch: Flux: V = 16.4 +/- 0.2, B-V=-0.3 +/-0.1 Comments: Coordinates have been measured by GASP in cycle 3 Target_Number: 4 Target_Name: STAR-0122+200 Alternate_Names: PG0122+200 Description: STAR,PG1159 STAR,PULSATING VARIABLE Position: RA = 1H 25M 22.49S +/- 0.04S, DEC = 20D 17' 56.9" +/- 0.5", PLATE-ID = 021K Equinox: J2000 Epoch: 1982.890 Flux: V = 16.7 +/- 0.2, B-V=-0.3 +/-0.1 Comments: Coordinates are from an inventory GASP measurement by Karla Target_Number: 5 Target_Name: STAR-0130-1937 Alternate_Names: GSC5854-00201, PHL1025 Description: STAR,PG1159 STAR Position: RA = 1H 32M 39.32S +/- 0.02S, DEC = -19D 21' 40.6" +/- 0.32", PLATE-ID = 02J7 Equinox: J2000 Epoch: 1980.787 Flux: V = 16.2 +/- 0.2, B-V=-0.3 +/-0.1 Comments: Coordinates are from GSC Target_Number: 6 Target_Name: STAR-070459+615309 Alternate_Names: HS0704+6153 Description: STAR,PG1159 STAR Position: RA = 7H 9M 32.24S +/- 0.07S, DEC = 61D 48' 19.4" +/- 0.5", PLATE-ID = 034U Equinox: J2000 Epoch: 1983.850 Flux: V = 17.2 +/- 0.2, B-V=-0.3 +/-0.1 Comments: Coordinates are from an inventory GASP measurement by Karla Target_Number: 7 Target_Name: STAR-151709+740300 Alternate_Names: HS1517+7403 Description: STAR,PG1159 STAR Position: RA = 15H 16M 46.36S +/- 0.11S, DEC = 73D 52' 5.9" +/- 0.5", PLATE-ID = 01L5 Equinox: J2000 Epoch: 1983.294 Flux: V = 16.7 +/- 0.2, B-V=-0.3 +/-0.1 Comments: Coordinates are from an inventory GASP measurement by Karla Target_Number: 8 Target_Name: STAR-2131+066 Alternate_Names: PG2131+066 Description: STAR,PG1159 STAR,PULSATING VARIABLE Position: RA = 21H 34M 8.22S +/- 0.03S, DEC = 6D 50' 57.4" +/- 0.5", PLATE-ID = 02V9 Equinox: J2000 Epoch: 1983.849 Flux: V = 16.7 +/- 0.2, B-V=-0.3 +/-0.1 Comments: Coordinates are from an inventory GASP measurement by Karla Visits Visit_Number: 1 Visit_Requirements: Visit_Comments: Exposure_Number: 1 Target_Name: STAR-1520+525 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 9.0S Special_Requirements: ONBOARD ACQ FOR 2 Comments: STEP-TIME=1.0s, EXPECT 500 CNTS Exposure_Number: 2 Target_Name: STAR-1520+525 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1170-1456 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 25.175M Special_Requirements: Comments: Visit_Number: 2 Visit_Requirements: Visit_Comments: Exposure_Number: 1 Target_Name: STAR-1424+535 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 14.4S Special_Requirements: ONBOARD ACQ FOR 2 Comments: STEP-TIME=1.6S, EXPECT 500 CNTS Exposure_Number: 2 Target_Name: STAR-1424+535 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1170-1456 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 24.05M Special_Requirements: Comments: Visit_Number: 3 Visit_Requirements: Visit_Comments: Exposure_Number: 1 Target_Name: STAR-1707+427 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 20.7S Special_Requirements: ONBOARD ACQ FOR 2 Comments: STEP-TIME=2.3S, EXPECT 500 CNTS Exposure_Number: 2 Target_Name: STAR-1707+427 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1170-1456 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 21.25M Special_Requirements: Comments: Visit_Number: 4 Visit_Requirements: Visit_Comments: Exposure_Number: 1 Target_Name: STAR-0122+200 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 20.7S Special_Requirements: ONBOARD ACQ FOR 2 Comments: STEP-TIME=2.3S, EXPECT 500 CNTS Exposure_Number: 2 Target_Name: STAR-0122+200 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1170-1456 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 19.3M Special_Requirements: Comments: Visit_Number: 5 Visit_Requirements: Visit_Comments: Exposure_Number: 1 Target_Name: STAR-0130-1937 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 13.5S Comments: STEP-TIME=1.5S, EXPECT 500 CNTS Special_Requirements: ONBOARD ACQ FOR 2 Exposure_Number: 2 Target_Name: STAR-0130-1937 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1170-1456 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 20.66M Special_Requirements: Comments: Visit_Number: 6 Visit_Requirements: CVZ Visit_Comments: Without CVZ requirement the available exposure time for this faint target is too short for the desired SNR Exposure_Number: 1 Target_Name: STAR-070459+615309 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 32.4S Special_Requirements: ONBOARD ACQ FOR 2-3 Comments: STEP-TIME=3.6S, EXPECT 500 CNTS Exposure_Number: 2 Target_Name: STAR-070459+615309 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1170-1456 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 27.65M Special_Requirements: Comments: Exposure_Number: 3 Target_Name: STAR-070459+615309 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1170-1456 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 27.65M Special_Requirements: Comments: Visit_Number: 7 Visit_Requirements: Visit_Comments: Exposure_Number: 1 Target_Name: STAR-151709+740300 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 20.7S Special_Requirements: ONBOARD ACQ FOR 2 Comments: STEP-TIME=2.3S, EXPECT 500 CNTS Exposure_Number: 2 Target_Name: STAR-151709+740300 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1170-1456 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 24.79M Special_Requirements: Comments: Visit_Number: 8 Visit_Requirements: Visit_Comments: Exposure_Number: 1 Target_Name: STAR-2131+066 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 20.7S Special_Requirements: ONBOARD ACQ FOR 2 Comments: STEP-TIME=2.3S, EXPECT 500 CNTS Exposure_Number: 2 Target_Name: STAR-2131+066 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1170-1456 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 19.18M Special_Requirements: Comments: Data_Distribution Medium: 8MM ! 8MM or 6250BPI or 1600BPI Blocking_Factor: 10 ! 10 or 1 Ship_To: PI_Address ! STSCI or PI_Address or ! PI Address from Phase I is: ! !Sternwartstr. 7 !D-96049 Bamberg ,Germany !Recipient_Email: ! Needed if Ship_To: is not PI_Address ! ! ! End of 5866