Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5581 Report Date: 18-Jul-95:17:41 Version: ********** Check-in Date: ********** 1.Proposal Title: TIME-RESOLVED SPECTROSCOPY OF THE PULSATING DA WHITE DWARF DN DRACONIS: CYCLE4 MEDIUM ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID HOT STARS GO/DD Sub Category WHITE DWARFS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone R. edward Nather UNIVERSITY OF TEXAS USA 512-471-3000 ------------------------------------------------------------------------------------ 7. Abstract The pulsation modes of white dwarfs are identified by indices (l,m,k). The mode indices have not been identified with certainty for any pulsation of any DA white dwarf. If the index l of their pulsations could be measured, the masses of their outer hydrogen layers could be determined. This is an important result because the thickness of the hydrogen layer directly tests models for the ejection of planetary nebulae and theories for the spectral evolution of white dwarfs. The amplitudes of the pulsations of DA white dwarfs depend strongly on l at wavelengths less than 3000 A. Time resolved spectroscopy of the pulsations at ultraviolet wavelengths will, therefore, allow a direct determination of l. DN Draconis (= G226-29) is a pulsating DA white dwarf. Three of its pulsation modes are simultaneously excited at periods near 109.3 s; they add together in the light curve to give a beat period of 17.2 hr. We will use the FOS with the blue Digicon and the G160L grating in RAPID readout mode to obtain ultraviolet spectrophotometry of G226-29 with a sampling interval of 10 seconds. We will observe G226-29 for 11 consecutive orbits covering one cycle of its 17.2 hour beat period, accumulating about 7.2 hours of on-target data. Power spectra of the flux variations will yield wavelength-dependent amplitudes for each pulsation and thus the value of l for each pulsation. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 7.60 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5581 PI: R. edward Nather Proposal Title: TIME-RESOLVED SPECTROSCOPY OF THE PULSATING DA WHITE DWARF DN DRACONIS: CYCLE4 MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ R. Edward Nather 3550 USA Edward L Robinson 3550 USA S. O Kepler 4460 BRAZIL ------------------------------------------------------------------------------------ 3. Description of proposed observations. The magnitude of DN Dra places it perilously close to the bright limit for ACQ/BINARY. To insure that we acquire DN Dra without going over the bright limit, we are using ACQ/PEAK instead of ACQ/BINARY. Because we will be doing spectrophotometry and will need good centering in the 1.0 aperture, we are using a three-stage peakup. DN Dra does not vary by enough to confuse the ACQ/PEAK centering. DN Dra pulsates in three pulsation modes simultaneously. All three have periods near 109 seconds. We are using the RAPID readout mode with a READ- TIME = 10 seconds in order to fully resolve the pulsations; the signal-to-noise ratio of the data is not relevant for the choice of READ-TIME. A READ-TIME shorter than 10 seconds is not necessary and would add to the data management difficulties. The three pulsations beat together to give a beat period of 17.2068 hours. To differentiate the three pulsations it is necessary to sample a substantial fraction of the beat period. The beat period is known accurately and the beat cycle repeats exactly, so it is not necessary to observe a beat cycle all at once. There is a great advantage to breaking the observation into parts because the individual parts will be much easier to schedule than one large observation would be (indeed, we have been told that it is impossible to schedule an unbroken observation lasting 17.2 hours). We have, therefore, broken the observation into 6 parts, each part sampling a different section of the beat cycle. The sequence consists of 1) Acquire DN Dra with the ACQ/PEAK mode, using a triple peakup. 2) Observe DN DRA with the FOS/BLUE in the RAPID mode with READ- TIME= 10 seconds and a total exposure of 2.854 hours. Page 3 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The only spacecraft that can obtain ultraviolet spectra with sampling intervals short enough to resolve the pulsations of DA white dwarfs is HST. The schemes that have been used to resolve the pulsations of white dwarfs with IUE by "nodding" the spacecraft in time with the brightness variations do not really work because the white dwarfs are pulsating in several modes simultaneously (they are multiperiodic). The resulting observations "scramble" the pulsation modes and cannot be used to determine l by our method. We need to measure the relative amplitudes of the pulsations to one percent or better to distinguish the value of l. We will do this by taking power spectra of the flux variations at each wavelength in the time-resolved FOS spectra. We will easily accumulate enough photons to achieve this level of accuracy. A more interesting question is whether spurious periodicities will be introduced into the data by, for example, HST jitter. Observations with the HST high speed photometer have demonstrated that any spurious periodicities near 109 seconds have amplitudes less than 0.1% (Taylor et al 1993, Ap. J., submitted). This level of precision cannot be obtained with IUE. Extensive high-speed photometry of G226-29 has been obtained from the ground and its light curve has been decomposed into its constituent pulsations (Kepler, Robinson, and Nather 1983, Ap.J., 271, 744). G226-29 was observed with the Whole Earth Telescope in 1992. G226-29 has been observed with IUE (e.g., Kepler and Nelen 1993, A.J., 105, 608). The IUE observations yielded an effective temperature for G226-29. We expect, however, that the HST observations will allow us to give an improved value for the effective temperature. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. It is NOT necessary to observe the 6 individual parts of this observation close together in time nor in any special sequence. They can be scheduled as 6 independent observations. They should, however, be scheduled within one year of each other. This project is extremely inefficient unless it is scheduled in the Continuous Viewing Zone, so we have been directed to use only CVZ time. We have been allocated 7.6 hours of CVZ spacecraft time. With the factor of 3 adjustment, this becomes 22.8 hours of spacecraft time reported by the RPSS resource estimator. It is acceptable to break the observations into more than 6 parts if necessary to schedule the observations. The only loss would be a small decrease in efficiency. Specifically, in going from 6 to 7 parts, the efficiency would drop from 75% to 71%. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. No special calibrations are required. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. None. ------------------------------------------------------------------------------------ 9. Description of previous HST work. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). The University of Texas will provide office space, computer facilities (SPARCstation 2 and 10 workstations), and library facilities in the Department of Astronomy. We will attempt to acquire contemporaneous observations of G226-29 at McDonald Observatory, which is owned and operated by the University of Texas. ------------------------------------------------------------------------------------ 11. Address Information Page 4 Name: R. EDWARD NATHER Category: PI Institution: 3550 Address: DEPARTMENT OF ASTRONOMY UNVERSITY OF TEXAS City: AUSTIN State: TX Zip Code: 78712 Country: USA Telephone: 512-471-3000 Telex (or e-mail): nather@astro.as.utexas.edu ------------------------------------------------------------------------------------ Name: EDWARD L ROBINSON Category: CON Institution: 3550 Address: DEPARTMENT OF ASTRONOMY UNIVERSITY OF TEXAS City: AUSTIN State: TX Zip Code: 78712 Country: USA Telephone: 512-471-3000 Telex (or e-mail): elr@astro.as.utexas.edu ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5581 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 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 DN-DRA G226- A,120,177 PLATE-ID = 00T2, J2000 1 V = 12.24 +/- 0.02 29 RA = 16H 48M 25.28S +/- 2 B-V = 0.16 +/- 0.02 WD1647+591 0.03S, 3 TYPE = DA4 DEC = +59D 03' 27.5" +/- 4 E(B-V) = 0.00 0.2" Comments: THIS IS A CVZ TARGET Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B 1983.61 0.0184 +/- 0.0002 -0.3030 +/- 0.0040 0.0800 +/- 0.0040 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5581 [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1.1 DN-DRA FOS/BL ACQ/ 4.3 G190H SCAN-STEP- 1 10.0S 1 1 CYCLE 4 / 1.1-6.4 PEAK Y=1.204 2 ONBOARD ACQ FOR SEARCH-SIZE-X=1 3 1.2 SEARCH-SIZE-Y=3 4 Comments: BRIGHT VARIABLE STAR. UV FLUCTUATIONS EXPECTED. THE OBSERVATIONS MUST BE MADE IN THE CVZ. ------------------------------------------------------------------------------------------------------------------------------------ 1.2 DN-DRA FOS/BL ACQ/ 1.0 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.602 2 1.3 SCAN-STEP- 3 Y=0.602 4 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 1.3 DN-DRA FOS/BL ACQ/ 0.5 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.30 2 1.4 SCAN-STEP- 3 Y=0.30 4 SEARCH-SIZE-X=3 SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 1.4 DN-DRA FOS/BL RAPID 1.0 G160L READ-TIME=10.0 1 171.5M 1 1 ZERO-PHASE 2 JD2449400.0 +/- 3 0.0D PERIOD 4 0.71695D +/- 0.00002D PHASE 0.00 +/- Comments: THE TOTAL INTEGRATION TIME IS 0.05 SET BY THE NEED TO COVER THE ENTIRE PULSATION BEAT PERIOD, SO S/N IS NOT RELEVANT. ------------------------------------------------------------------------------------------------------------------------------------ 2.1 DN-DRA FOS/BL ACQ/ 4.3 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK Y=1.204 2 2.2 SEARCH-SIZE-X=1 3 SEARCH-SIZE-Y=3 4 Comments: BRIGHT VARIABLE STAR. UV FLUCTUATIONS EXPECTED. THE OBSERVATIONS MUST BE MADE IN THE CVZ. ------------------------------------------------------------------------------------------------------------------------------------ 2.2 DN-DRA FOS/BL ACQ/ 1.0 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.602 2 2.3 SCAN-STEP- 3 Y=0.301 4 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5581 [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 2.3 DN-DRA FOS/BL ACQ/ 0.5 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.30 2 2.4 SCAN-STEP- 3 Y=0.30 4 SEARCH-SIZE-X=3 SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 2.4 DN-DRA FOS/BL RAPID 1.0 G160L READ-TIME=10.0 1 171.5M 1 1 PHASE 0.167 +/- 2 0.05 OF REF 1.4 3 4 Comments: THE TOTAL INTEGRATION TIME IS SET BY THE NEED TO COVER THE ENTIRE PULSATION BEAT PERIOD, SO S/N IS NOT RELEVANT. ------------------------------------------------------------------------------------------------------------------------------------ 3.1 DN-DRA FOS/BL ACQ/ 4.3 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK Y=1.204 2 3.2 SEARCH-SIZE-X=1 3 SEARCH-SIZE-Y=3 4 Comments: BRIGHT VARIABLE STAR. UV FLUCTUATIONS EXPECTED. THE OBSERVATIONS MUST BE MADE IN THE CVZ. ------------------------------------------------------------------------------------------------------------------------------------ 3.2 DN-DRA FOS/BL ACQ/ 1.0 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.602 2 3.3 SCAN-STEP- 3 Y=0.301 4 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 3.3 DN-DRA FOS/BL ACQ/ 0.5 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.30 2 3.4 SCAN-STEP- 3 Y=0.30 4 SEARCH-SIZE-X=3 SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 3.4 DN-DRA FOS/BL RAPID 1.0 G160L READ-TIME=10.0 1 171.5M 1 1 PHASE 0.333 +/- 2 0.05 OF REF 1.4 3 4 Comments: THE TOTAL INTEGRATION TIME IS SET BY THE NEED TO COVER THE ENTIRE PULSATION BEAT PERIOD, SO S/N IS NOT RELEVANT. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5581 [ 8] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 4.1 DN-DRA FOS/BL ACQ/ 4.3 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK Y=1.204 2 4.2 SEARCH-SIZE-X=1 3 SEARCH-SIZE-Y=3 4 Comments: BRIGHT VARIABLE STAR. UV FLUCTUATIONS EXPECTED. THE OBSERVATIONS MUST BE MADE IN THE CVZ. ------------------------------------------------------------------------------------------------------------------------------------ 4.2 DN-DRA FOS/BL ACQ/ 1.0 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.602 2 4.3 SCAN-STEP- 3 Y=0.301 4 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 4.3 DN-DRA FOS/BL ACQ/ 0.5 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.30 2 4.4 SCAN-STEP- 3 Y=0.30 4 SEARCH-SIZE-X=3 SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 4.4 DN-DRA FOS/BL RAPID 1.0 G160L READ-TIME=10.0 1 171.5M 1 1 PHASE 0.5 +/- 0.05 2 OF REF 1.4 3 4 Comments: THE TOTAL INTEGRATION TIME IS SET BY THE NEED TO COVER THE ENTIRE PULSATION BEAT PERIOD, SO S/N IS NOT RELEVANT. ------------------------------------------------------------------------------------------------------------------------------------ 5.1 DN-DRA FOS/BL ACQ/ 4.3 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK Y=1.204 2 5.2 SEARCH-SIZE-X=1 3 SEARCH-SIZE-Y=3 4 Comments: BRIGHT VARIABLE STAR. UV FLUCTUATIONS EXPECTED. THE OBSERVATIONS MUST BE MADE IN THE CVZ. ------------------------------------------------------------------------------------------------------------------------------------ 5.2 DN-DRA FOS/BL ACQ/ 1.0 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.602 2 5.3 SCAN-STEP- 3 Y=0.301 4 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5581 [ 9] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 5.3 DN-DRA FOS/BL ACQ/ 0.5 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.30 2 5.4 SCAN-STEP- 3 Y=0.30 4 SEARCH-SIZE-X=3 SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 5.4 DN-DRA FOS/BL RAPID 1.0 G160L READ-TIME=10.0 1 171.5M 1 1 PHASE 0.667 +/- 2 0.05 OF REF 1.4 3 4 Comments: THE TOTAL INTEGRATION TIME IS SET BY THE NEED TO COVER THE ENTIRE PULSATION BEAT PERIOD, SO S/N IS NOT RELEVANT. ------------------------------------------------------------------------------------------------------------------------------------ 6.1 DN-DRA FOS/BL ACQ/ 4.3 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK Y=1.204 2 6.2 SEARCH-SIZE-X=1 3 SEARCH-SIZE-Y=3 4 Comments: BRIGHT VARIABLE STAR. UV FLUCTUATIONS EXPECTED. THE OBSERVATIONS MUST BE MADE IN THE CVZ. ------------------------------------------------------------------------------------------------------------------------------------ 6.2 DN-DRA FOS/BL ACQ/ 1.0 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.602 2 6.3 SCAN-STEP- 3 Y=0.301 4 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 6.3 DN-DRA FOS/BL ACQ/ 0.5 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.30 2 6.35 SCAN-STEP- 3 Y=0.30 4 SEARCH-SIZE-X=3 SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 6.35 DN-DRA FOS/BL ACQ/ 0.3 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.172 2 6.37 SCAN-STEP- 3 Y=0.172 4 SEARCH-SIZE-X=3 SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 6.37 DN-DRA FOS/BL ACQ/ 0.3 G190H SCAN-STEP- 1 10.0S 1 1 ONBOARD ACQ FOR PEAK X=0.17 2 6.4 SCAN-STEP- 3 Y=0.17 4 SEARCH-SIZE-X=4 SEARCH-SIZE-Y=4 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5581 [ 10] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 6.4 DN-DRA FOS/BL RAPID 1.0- G160L READ-TIME=10.0 1 171.5M 1 1 PHASE 0.833 +/- PAIR-A STEP- 2 0.05 OF REF 1.4 PATT=SINGLE 3 4 Comments: THE TOTAL INTEGRATION TIME IS SET BY THE NEED TO COVER THE ENTIRE PULSATION BEAT PERIOD, SO S/N IS NOT RELEVANT. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5581 [ 11] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK RAPID ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SCAN-STEP-Y=1.204 SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP-X=0.602 SCAN-STEP-Y=0.602 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP-X=0.30 SCAN-STEP-Y=0.30 SEARCH-SIZE-X=3 READ-TIME= 10.0 SCAN-STEP-Y=0.301 SCAN-STEP-X=0.172 SCAN-STEP-Y=0.172 SCAN-STEP-X=0.17 SCAN-STEP-Y=0.17 SEARCH-SIZE-X=4 SEARCH-SIZE-Y=4 STEP-PATT=SINGLE ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO/DD ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 7.60 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category WHITE DWARFS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4 / 1.1-6.4; ONBOARD ACQ FOR 1.2 ONBOARD ACQ FOR 1.3 ONBOARD ACQ FOR 1.4 ZERO-PHASE JD2449400.0 +/- 0.0D; PERIOD 0.71695D +/- 0.00002D; PHASE 0.00 +/- 0.05 ONBOARD ACQ FOR 2.2 ONBOARD ACQ FOR 2.3 ONBOARD ACQ FOR 2.4 PHASE 0.167 +/- 0.05 OF REF 1.4 ONBOARD ACQ FOR 3.2 ONBOARD ACQ FOR 3.3 ONBOARD ACQ FOR 3.4 PHASE 0.333 +/- 0.05 OF REF 1.4 ONBOARD ACQ FOR 4.2 ONBOARD ACQ FOR 4.3 ONBOARD ACQ FOR 4.4 PHASE 0.5 +/- 0.05 OF REF 1.4 ONBOARD ACQ FOR 5.2 ONBOARD ACQ FOR 5.3 ONBOARD ACQ FOR 5.4 PHASE 0.667 +/- 0.05 OF REF 1.4 ONBOARD ACQ FOR 6.2 ONBOARD ACQ FOR 6.3 ONBOARD ACQ FOR 6.35 ONBOARD ACQ FOR 6.37 ONBOARD ACQ FOR 6.4 PHASE 0.833 +/- 0.05 OF REF 1.4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G190H G160L ------------------------------------------------------------------------------------------------------------------------------------ Target Names DN-DRA G226-29 WD1647+591 ------------------------------------------------------------------------------------------------------------------------------------