Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4307c Report Date: 09-May-96:19:31 Version: ********** Check-in Date: ********** 1.Proposal Title: RADIAL AND NONRADIAL PULSATIONS IN HOT WHITE DWARFS -- CYCLE 3 MEDIUM ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID HOT STARS GO Sub Category WHITE DWARFS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Steven D. Kawaler IOWA STATE UNIVERSITY USA ------------------------------------------------------------------------------------ 7. Abstract We propose to use the High Speed Photometer to search for the previously unobserved phenomenon of RADIAL pulsations in white dwarfs. Three classes of NONRADIALLY pulsating white dwarfs are known, with pulsation periods ranging from several minutes to half an hour. Theory predicts that stars slightly hotter than the nonradial instability strips for DA, DB, and PG 1159-type white dwarfs should be unstable to radial pulsations, with periods between 0.1 and 10 seconds. We have received Cycle 2 HSP time to search several DA and DB candidates for these predicted rapid pulsations. In Cycle 3 we propose to use HSP to search for the predicted radial pulsations in 3 members of the PG 1159 class. High-speed UV photometry is free from atmospheric scintillation, and takes advantage of the larger stellar fluxes and larger pulsation amplitudes for these extremely hot (above 125,000 K) stars. Our targets are three known nonradial pulsators (two are central stars in planetary nebulae), so that the observations will also provide information on the wavelength dependence of the nonradial pulsation amplitudes. The presence (or absence) of radial pulsations will provide significant new information for (or challenges to) our understanding of white-dwarf pulsations, structure, and evolution. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.69 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HSP ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4307c PI: Steven D. Kawaler Proposal Title: RADIAL AND NONRADIAL PULSATIONS IN HOT WHITE DWARFS -- CYCLE 3 MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Steven D. Kawaler IOWA STATE UNIVERSITY USA Howard E. Bond STSCI USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We will obtain high-speed photometry of hot DOZ white dwarfs at ultraviolet wavelengths with the HSP. We will use a time resolution of 0.02 sec. To maximize the count rates on these hot (140,000K) white dwarfs, we will use the F140LP filter configuration with one of the UV IDTs. We will observe through the 10" acquisition aperture to maximize the count rate. Run lengths will range from 30 to 135 minutes (uninterrupted). ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. One of our targets, K1-16, lies within the CVZ. We will observe this star for 135 continuous minutes to improve the signal-to-noise and therefore improve the amplitude sensitivity for radial pulsations. This longer exposure time will also allow us to study the nonradial pulsations in this object by giving data over several cycles of the 1700 second dominant pulsation mode. ------------------------------------------------------------------------------------ 11. Address Information Name: STEVEN D. KAWALER Category: PI Institution: Iowa State University Address: DEPARTMENT OF PHYSICS AND ASTRONOMY City: AMES State: IA Zip Code: 50011 Country: USA Telephone: 515-294-9728 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4307c [ 3] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 PG1159-035 A,175,176 RA=12H01M45.98S +/- 0.33", J2000 1 V=14.8,TYPE=PG1159 GW-VIRGINIS DEC=-03D45'40.7" +/- 0.33", PLATE-ID=03O9 ------------------------------------------------------------------------------------------------------------------------------------ 2 K1-16 A,184,175,176 RA=18H21M52.02S +/- 0.33", J2000 1 V=15.1,TYPE=PG1159 GSC4222-830 DEC=+64D21'53.9" +/- 0.33", 1 B-V=-0.4 PLATE-ID=00T0 ------------------------------------------------------------------------------------------------------------------------------------ 3 RXJ2117+3412 A,184,175,176 RA=21H17M08.29S +/- 0.33", J2000 1 V=13.2,TYPE=PG1159 DEC=+34D12'27.6" +/- 0.33", PLATE-ID=01W5 Comments: ROSAT SOURCE ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4307c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PG1159-035 HSP/ ACQ DATA- 1 2.0M 12 1 1 ONBOARD ACQ FOR 2 UV2 FORMAT=WORD PCS MODE F CYCLE 3 ------------------------------------------------------------------------------------------------------------------------------------ 2 PG1159-035 HSP/ SINGLE 10.0 F140LP SAMPLE- 1 30M 1 1 NON-INT UV2 TIME=0.02 PCS MODE F PRECISION=HIGH CYCLE 3 ------------------------------------------------------------------------------------------------------------------------------------ 2.5 DARK S/C DATA NONE FORMAT=FN 1 0S 1 PAR WITH 2 CRIT OBS CYCLE 3 Comments: THE FN FORMAT IS SPECIFIED IN ORDER TO ASSURE THAT THE ENGINEERING DATA ARE RECORDED AT 32 KBPS, FOR SUBSEQUENT ATTEMPTS TO REMOVE GUIDING JITTER FROM THE HSP PHOTOMETRY ------------------------------------------------------------------------------------------------------------------------------------ 3 K1-16 HSP/ ACQ DATA- 1 2.0M 12 1 1 ONBOARD ACQ FOR 4 UV2 FORMAT=WORD PCS MODE F CYCLE 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 K1-16 HSP/ SINGLE 10.0 F140LP SAMPLE- 1 135M 1 1 NON-INT UV2 TIME=0.05 PCS MODE F PRECISION=HIGH CYCLE 3 Comments: CONTINUOUS VIEWING ZONE (CVZ) TARGET ------------------------------------------------------------------------------------------------------------------------------------ 4.5 DARK S/C DATA NONE FORMAT=FN 1 0S 1 PAR WITH 4 CRIT OBS CYCLE 3 Comments: THE FN FORMAT IS SPECIFIED IN ORDER TO ASSURE THAT THE ENGINEERING DATA ARE RECORDED AT 32 KBPS, FOR SUBSEQUENT ATTEMPTS TO REMOVE GUIDING JITTER FROM THE HSP PHOTOMETRY ------------------------------------------------------------------------------------------------------------------------------------ 5 RXJ2117+341 HSP/ ACQ DATA- 1 1.0M 12 1 1 ONBOARD ACQ FOR 6- 2 UV2 FORMAT=WORD 6.2 PCS MODE F CYCLE 3 ------------------------------------------------------------------------------------------------------------------------------------ 6 RXJ2117+341 HSP/ SINGLE 10.0 F140LP SAMPLE- 1 34M 1 1 NON-INT 2 UV2 TIME=0.02 PCS MODE F PRECISION=HIGH CYCLE 3 ------------------------------------------------------------------------------------------------------------------------------------ 6.2 RXJ2117+341 HSP/ SINGLE 10.0 F140LP SAMPLE- 1 34M 1 1 NON-INT 2 UV2 TIME=0.02 PCS MODE F PRECISION=HIGH CYCLE 3 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4307c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 6.3 DARK S/C DATA NONE FORMAT=FN 1 0S 1 PAR WITH 6 CRIT OBS CYCLE 3 Comments: THE FN FORMAT IS SPECIFIED IN ORDER TO ASSURE THAT THE ENGINEERING DATA ARE RECORDED AT 32 KBPS, FOR SUBSEQUENT ATTEMPTS TO REMOVE GUIDING JITTER FROM THE HSP PHOTOMETRY ------------------------------------------------------------------------------------------------------------------------------------ 6.4 DARK S/C DATA NONE FORMAT=FN 1 0S 1 PAR WITH 6.2 CRIT OBS CYCLE 3 Comments: THE FN FORMAT IS SPECIFIED IN ORDER TO ASSURE THAT THE ENGINEERING DATA ARE RECORDED AT 32 KBPS, FOR SUBSEQUENT ATTEMPTS TO REMOVE GUIDING JITTER FROM THE HSP PHOTOMETRY ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4307c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HSP/UV2 S/C ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ SINGLE DATA ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters DATA-FORMAT=WORD SAMPLE-TIME=0.02 PRECISION=HIGH FORMAT=FN SAMPLE-TIME=0.05 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.69 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category WHITE DWARFS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2; PCS MODE F; CYCLE 3 NON-INT; PAR WITH 2; CRIT OBS; ONBOARD ACQ FOR 4; CYCLE 3; PAR WITH 4; ONBOARD ACQ FOR 6-6.2; PAR WITH 6; PAR WITH 6.2; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F140LP ------------------------------------------------------------------------------------------------------------------------------------ Target Names PG1159-035 GW-VIRGINIS K1-16 GSC4222-830 RXJ2117+3412 ------------------------------------------------------------------------------------------------------------------------------------