Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4344c Report Date: 09-May-96:19:33 Version: ********** Check-in Date: ********** 1.Proposal Title: THE MASS OF THE WHITE DWARF IN V471 TAURI -- CYCLE 3 HIGH ------------------------------------------------------------------------------------ 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 Howard E. Bond STSCI USA ------------------------------------------------------------------------------------ 7. Abstract V471 Tau is an eclipsing binary in the Hyades cluster whose components are a DA white dwarf and a detached K2 V main-sequence star. It presents a unique opportunity for direct determination of the mass of a white dwarf, except that it is impossible to obtain the velocity curve of the white dwarf from the ground because its light is swamped by that of the K dwarf. We propose to determine its velocity curve using the GHRS at Lyman-alpha, where the white dwarf has a strong absorption feature, and thus obtain only the fourth fundamentally determined mass of a white dwarf. As bonuses, our observations will also: (1) provide constraints on the presence of photospheric metals accreted at the white dwarf's magnetic poles from the K2 V star's wind; (2) allow us to search for modulation of metal lines at the 9.25-min rotation period of the white dwarf, which is expected if the metals are concentrated at the magnetic poles; (3) measure the gravitational redshift of the white dwarf; and (4) stringently constrain the magnetic field strength of the white dwarf by the presence or absence of Zeeman components of Lyman-alpha. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 2.05 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4344c PI: Howard E. Bond Proposal Title: THE MASS OF THE WHITE DWARF IN V471 TAURI -- CYCLE 3 HIGH ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Howard E. Bond STSCI USA Edward M. Sion VILLANOVA UNIVERSITY USA John R. Stauffer CENTER FOR ASTROPHYSICS USA ------------------------------------------------------------------------------------ 2. Scientific Justification. (See original proposal for Scientific Justification) ------------------------------------------------------------------------------------ 3. Description of proposed observations. V471 Tau is an eclipsing binary containing a white dwarf (WD) and K dwarf (dK), with an orbital period of 12.5 hours. The WD is also known to rotate with a period of 9.25 minutes. In order to determine the RV amplitude of the WD component of V471 Tau, we will obtain two GHRS spectra each at orbital phases 0.25 and 0.75, centered at Lyman-alpha. Each of the total of four observations will have a duration of four WD rotation periods, i.e. 37 minutes. Each of the 37 -min runs will be broken into 16 individual spectra, i.e., four spectra per WD rotation. Due to deadtime between GHRS exposures, each individual exposure will be 1.92 min. The observing sequence (for each of the 4 independent observations) is: (1) acquire target in LSA; (2) acquire/peakup in SSA; (3) wavelength calibration (with no further carousel motions during the sequence); (4) the 16 science observations covering 37 min; (5) a final wavelength calibration. Note that deadtime between exposures is assumed to be 20 sec. The exposure time for each of the 16 spectra is thus 8 times 14.4 sec, which is the step-time for our chosen step-patt and comb, or 115.2 seconds. DARK TIME is requested to reduce the intensity of geocoronal Lyman-alpha but is not absolutely necessary. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. (See original proposal) ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. We will obtain wavelength calibrations before and after each of the four GHRS observations. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. (see original proposal) ------------------------------------------------------------------------------------ 8. Additional comments or special requests. (see original proposal) ------------------------------------------------------------------------------------ 9. Description of previous HST work. (See original proposal) ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). (See original proposal) ------------------------------------------------------------------------------------ 11. Address Information Page 3 Name: HOWARD E. BOND Category: PI Institution: STScI Address: 3700 SAN MARTIN DR. City: BALTIMORE State: MD Zip Code: 21218 Country: USA Telephone: 410-338-4718 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4344c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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 V471-TAU A,120,139,161 PLATE-ID=00FH, J2000 1 V=10.7,TYPE=DA BD+16D516 RA = 03H 50M 24.85S +/- 1 B-V=0.92 GSC1252-212 0.7", DEC = +17D 14' 47.7" +/- 0.7" Comments: FOR R.A. PROPER MOTION WE GIVE MU_ALPHA (S/YR) TIMES COS(DEC), IN ACCORDANCE WITH THE CYCLE 3 PROP. INSTRUCTIONS. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1993.00 0.0004 +/- 0.0000 -0.0140 +/- 0.0000 0.0000 +/- 0.0000 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4344c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 V471-TAU HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=3 1 1.8S 1 1 ONBOARD ACQ FOR 2 BRIGHT=RETURN CYCLE 3 / 1-20 Comments: THIS IS THE FIRST OBSERVATION TAKEN NEAR ORBITAL PHASE 0.23. STEP-TIME OF 0.2 SEC WAS USED. ------------------------------------------------------------------------------------------------------------------------------------ 2 V471-TAU HRS ACQ/ 0.25 MIRROR-N2 1 40S 1 1 ONBOARD ACQ FOR 3- PEAKUP 5 Comments: STEP-TIME OF 1.6 SEC WAS USED. ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE HRS ACCUM SC2 G160M 1215 STEP-PATT=05 1 DEF 1 CALIB FOR 4 NO FP-SPLIT=NO SLEW COMB=TWO PERIOD 0.5211833D +/- 0.0000001D ZERO-PHASE JD2440612.6696 +/- Comments: THIS IS A WAVELENGTH 0.0001D CALIBRATION TAKEN JUST BEFORE PHASE 0.23 +/- THE SCIENCE OBSERVATION. THERE 0.06 SHOULD BE NO CAROUSEL MOTION SEQ 3-5 NON-INT DURING OR AFTER THIS OBSERVATION, NOR DURING REST OF THE SEQUENCE. NO INTERRUPTIONS FOR SPYBAL AT ANY TIME. ------------------------------------------------------------------------------------------------------------------------------------ 4 V471-TAU HRS ACCUM 0.25 G160M 1215 STEP-PATT=05 16 115.2S 1 1 FP-SPLIT=NO COMB=TWO CENSOR=YES DOPPLER=ON Comments: THE 16 OBSERVATIONS SHOULD BE TAKEN CONTIGUOUSLY. THE EXPOSURE TIME HAS BEEN CHOSEN SUCH THAT THE 16 EXPOSURES WILL COVER EXACTLY 4 ROTATIONS OF THE WHITE DWARF, I.E. 37 UNINTERRUPTED MINUTES. ------------------------------------------------------------------------------------------------------------------------------------ 5 WAVE HRS ACCUM SC2 G160M 1215 STEP-PATT=05 1 DEF 1 CALIB FOR 4 NO FP-SPLIT=NO SLEW COMB=TWO Comments: THIS IS A WAVELENGTH CALIBRATION TAKEN JUST AFTER THE SCIENCE OBSERVATION. THERE SHOULD BE NO CAROUSEL MOTION BEFORE OR DURING THIS OBSERVATION. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4344c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 6 V471-TAU HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=3 1 1.8S 1 1 ONBOARD ACQ FOR 7 BRIGHT=RETURN CYCLE 3 Comments: STEP-TIME OF 0.2 SEC WAS USED. THIS IS THE SECOND, INDEPENDENT OBSERVATION TAKEN NEAR ORBITAL PHASE 0.23. ------------------------------------------------------------------------------------------------------------------------------------ 7 V471-TAU HRS ACQ/ 0.25 MIRROR-N2 1 40S 1 1 ONBOARD ACQ FOR 8- PEAKUP 10 Comments: STEP-TIME OF 1.6 SEC WAS USED. ------------------------------------------------------------------------------------------------------------------------------------ 8 WAVE HRS ACCUM SC2 G160M 1215 STEP-PATT=05 1 DEF 1 CALIB FOR 9 NO FP-SPLIT=NO SLEW COMB=TWO PERIOD 0.5211833D +/- 0.0000001D ZERO-PHASE JD2440612.6696 +/- Comments: THIS IS A WAVELENGTH 0.0001D CALIBRATION TAKEN JUST BEFORE PHASE 0.23 +/- THE SCIENCE OBSERVATION. THERE 0.06 SHOULD BE NO CAROUSEL MOTION SEQ 8-10 NON-INT DURING OR AFTER THIS OBSERVATION, NOR DURING REST OF THE SEQUENCE. NO INTERRUPTIONS FOR SPYBAL AT ANY TIME. ------------------------------------------------------------------------------------------------------------------------------------ 9 V471-TAU HRS ACCUM 0.25 G160M 1215 STEP-PATT=05 16 115.2S 1 1 FP-SPLIT=NO COMB=TWO CENSOR=YES DOPPLER=ON Comments: THE 16 OBSERVATIONS SHOULD BE TAKEN CONTIGUOUSLY. THE EXPOSURE TIME HAS BEEN CHOSEN SUCH THAT THE 16 EXPOSURES WILL COVER EXACTLY 4 ROTATIONS OF THE WHITE DWARF, I.E. 37 UNINTERRUPTED MINUTES. ------------------------------------------------------------------------------------------------------------------------------------ 10 WAVE HRS ACCUM SC2 G160M 1215 STEP-PATT=05 1 DEF 1 CALIB FOR 9 NO FP-SPLIT=NO SLEW COMB=TWO Comments: THIS IS A WAVELENGTH CALIBRATION TAKEN JUST AFTER THE SCIENCE OBSERVATION. THERE SHOULD BE NO CAROUSEL MOTION BEFORE OR DURING THIS OBSERVATION. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4344c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 11 V471-TAU HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=3 1 1.8S 1 1 ONBOARD ACQ FOR 12 BRIGHT=RETURN CYCLE 3 Comments: STEP-TIME OF 0.2 SEC WAS USED. THIS IS THE FIRST OBNSERVATION TAKEN NEAR ORBITAL PHASE 0.73. ------------------------------------------------------------------------------------------------------------------------------------ 12 V471-TAU HRS ACQ/ 0.25 MIRROR-N2 1 40S 1 1 ONBOARD ACQ FOR 13 PEAKUP -15 Comments: STEP-TIME OF 1.6 SEC WAS USED. ------------------------------------------------------------------------------------------------------------------------------------ 13 WAVE HRS ACCUM SC2 G160M 1215 STEP-PATT=05 1 DEF 1 CALIB FOR 14 NO FP-SPLIT=NO SLEW COMB=TWO PERIOD 0.5211833D +/- 0.0000001D ZERO-PHASE JD2440612.6696 +/- Comments: THIS IS A WAVELENGTH 0.0001D CALIBRATION TAKEN JUST BEFORE PHASE 0.73 +/- THE SCIENCE OBSERVATION. THERE 0.06 SHOULD BE NO CAROUSEL MOTION SEQ 13-15 NON-INT DURING OR AFTER THIS OBSERVATION, NOR DURING REST OF THE SEQUENCE. NO INTERRUPTIONS FOR SPYBAL AT ANY TIME. ------------------------------------------------------------------------------------------------------------------------------------ 14 V471-TAU HRS ACCUM 0.25 G160M 1215 STEP-PATT=05 16 115.2S 1 1 FP-SPLIT=NO COMB=TWO CENSOR=YES DOPPLER=ON Comments: THE 16 OBSERVATIONS SHOULD BE TAKEN CONTIGUOUSLY. THE EXPOSURE TIME HAS BEEN CHOSEN SUCH THAT THE 16 EXPOSURES WILL COVER EXACTLY 4 ROTATIONS OF THE WHITE DWARF, I.E. 37 UNINTERRUPTED MINUTES. ------------------------------------------------------------------------------------------------------------------------------------ 15 WAVE HRS ACCUM SC2 G160M 1215 STEP-PATT=05 1 DEF 1 CALIB FOR 14 NO FP-SPLIT=NO SLEW COMB=TWO Comments: THIS IS A WAVELENGTH CALIBRATION TAKEN JUST AFTER THE SCIENCE OBSERVATION. THERE SHOULD BE NO CAROUSEL MOTION BEFORE OR DURING THIS OBSERVATION. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4344c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 16 V471-TAU HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=3 1 1.8S 1 1 ONBOARD ACQ FOR 17 BRIGHT=RETURN CYCLE 3 Comments: STEP-TIME OF 0.2 SEC WAS USED. OBSERVATION TAKEN NEAR ORBITAL PHASE 0.73. ------------------------------------------------------------------------------------------------------------------------------------ 17 V471-TAU HRS ACQ/ 0.25 MIRROR-N2 1 40S 1 1 ONBOARD ACQ FOR 18 PEAKUP -20 Comments: STEP-TIME OF 1.6 SEC WAS USED. ------------------------------------------------------------------------------------------------------------------------------------ 18 WAVE HRS ACCUM SC2 G160M 1215 STEP-PATT=05 1 DEF 1 CALIB FOR 19 NO FP-SPLIT=NO SLEW COMB=TWO PERIOD 0.5211833D +/- 0.0000001D ZERO-PHASE JD2440612.6696 +/- Comments: THIS IS A WAVELENGTH 0.0001D CALIBRATION TAKEN JUST BEFORE PHASE 0.73 +/- THE SCIENCE OBSERVATION. THERE 0.06 SHOULD BE NO CAROUSEL MOTION SEQ 18-20 NON-INT DURING OR AFTER THIS OBSERVATION, NOR DURING REST OF THE SEQUENCE. NO INTERRUPTIONS FOR SPYBAL AT ANY TIME. ------------------------------------------------------------------------------------------------------------------------------------ 19 V471-TAU HRS ACCUM 0.25 G160M 1215 STEP-PATT=05 16 115.2S 1 1 FP-SPLIT=NO COMB=TWO CENSOR=YES DOPPLER=ON Comments: THE 16 OBSERVATIONS SHOULD BE TAKEN CONTIGUOUSLY. THE EXPOSURE TIME HAS BEEN CHOSEN SUCH THAT THE 16 EXPOSURES WILL COVER EXACTLY 4 ROTATIONS OF THE WHITE DWARF, I.E. 37 UNINTERRUPTED MINUTES. ------------------------------------------------------------------------------------------------------------------------------------ 20 WAVE HRS ACCUM SC2 G160M 1215 STEP-PATT=05 1 DEF 1 CALIB FOR 19 NO FP-SPLIT=NO SLEW COMB=TWO Comments: THIS IS A WAVELENGTH CALIBRATION TAKEN JUST AFTER THE SCIENCE OBSERVATION. THERE SHOULD BE NO CAROUSEL MOTION BEFORE OR DURING THIS OBSERVATION. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4344c [ 9] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE=3 BRIGHT=RETURN STEP-PATT=05 FP-SPLIT=NO COMB=TWO CENSOR=YES DOPPLER=ON ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 2.05 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category WHITE DWARFS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2; CYCLE 3 / 1-20 ONBOARD ACQ FOR 3-5 CALIB FOR 4 NO SLEW; PERIOD 0.5211833D +/- 0.0000001D; ZERO-PHASE JD2440612.6696 +/- 0.0001D; PHASE 0.23 +/- 0.06; SEQ 3-5 NON-INT CALIB FOR 4 NO SLEW ONBOARD ACQ FOR 7; CYCLE 3 ONBOARD ACQ FOR 8-10 CALIB FOR 9 NO SLEW; SEQ 8-10 NON-INT CALIB FOR 9 NO SLEW ONBOARD ACQ FOR 12; ONBOARD ACQ FOR 13-15 CALIB FOR 14 NO SLEW; PHASE 0.73 +/- 0.06; SEQ 13-15 NON-INT CALIB FOR 14 NO SLEW ONBOARD ACQ FOR 17; ONBOARD ACQ FOR 18-20 CALIB FOR 19 NO SLEW; SEQ 18-20 NON-INT CALIB FOR 19 NO SLEW ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names V471-TAU BD+16D516 GSC1252-212 ------------------------------------------------------------------------------------------------------------------------------------