Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5405 Report Date: 18-Jul-95:17:19 Version: ********** Check-in Date: ********** 1.Proposal Title: THE HIGH MASS WHITE DWARF IN HR 8210 CYCLE 4 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 Wayne B Landsman HUGHES STX USA (301)-286-3625 ------------------------------------------------------------------------------------ 7. Abstract We have recently identified the strong EUV source HR 8210 as a Sirius-like binary consisting of an A-type star and a massive (M=1.15 (+0.05,-0.15) Msun) white dwarf. We propose to observe the white dwarf Lyman-ALPHA profile at radial velocity conjunction and at both quadratures during the 22 day orbit to measure the gravitational redshift and the orbital velocity amplitude. These measurements will provide estimates of the white dwarf mass independent of a mass-radius relation, and thus provide a fundamental test of the Hamada-Salpeter relation at high white dwarf masses. Our observations will also yield an accurate Lyman-ALPHA profile for a gravity determination, an estimate of the interstellar HI column density, and a search for C III 1175 and Si III 1206 metal lines in the white dwarf. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 6.17 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 5405 PI: Wayne B Landsman Proposal Title: THE HIGH MASS WHITE DWARF IN HR 8210 CYCLE 4 MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Wayne B Landsman 3480 USA Theodore Simon 2190 USA Pierre Bergeron 4648 CANADA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We will obtain 60 minute Lyman-ALPHA observations of HR 8210 with the G160M grating at the both radial velocity quadratures and at the conjunction with the white dwarf in front. These three observations correspond to phases 0.0, 0.5 and 0.25 in the spectroscopic orbit given by Latham et al. (1994). During the conjunction, we will also obtain a spectrum centered at 1175 A to search for C III absorption, and to better define the blue wing of the Lyman-ALPHA profile, which was poorly observed with IUE. We will use the large aperture to maximize the signal to noise of the Lyman-ALPHA profile. Contamination from the gecoronal emission will be limited to one or two diodes in the core of the profile. We will check the wavelength calibration in two ways. First, we will obtain a wavelength calibration at Lyman-ALPHA prior to each of the three Lyman-ALPHA observations. In addition, we will obtain a 3 minute G160M observation of the stellar Al III lines near 1850 A star to verify that the GHRS wavelength scale matches the known radial velocity orbit of the Am primary. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The white dwarf in HR 8210 is separated from the much brighter Am primary by only 0.005 arc sec, and thus is not detectable at wavelengths longer than 1500 A. The white dwarf was first discovered from our low-dispersion IUE observations (Landsman et al PASP, 105, 841). High-resolution and high signal to noise ultraviolet observations are required to measure the orbital and gravitational redshift velocities. These observations are not possible with high-dispersion IUE observations because the optimal exposure times are too long (43 hours), the signal to noise is limited (< 20) by fixed pattern noise, and the expected overexposure at 1900 A due to the Am primary would exceed the current safe limits for IUE. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. We are requesting observations during radial velocity conjunction (with the white dwarf in front) and the two quadratures during 21.7 day period orbit of HR 8210. There is no need for these three observations to be in the same orbit, and the observations can be within +-1 day of the specified phase. These timed observations are important to measure the orbital velocity amplitude of the white dwarf, and to distinguish between stellar and interstellar features. However, the observations at these phases is not absolutely essential for our primary goal of measuring the gravitational redshift. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. We request that an wavelength calibration be taken prior to each of the three observations of the Lyman alpha line of HR 8210. An accurate wavelength calibration is essential for our velocity measurement ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Compute facilities for the processing, analysis, and theoretical modeling of HST data Page 3 ------------------------------------------------------------------------------------ 11. Address Information Name: WAYNE B LANDSMAN Category: PI Institution: 3480 Address: HUGHES STX CODE 681 NASA/GSFC City: GREENBELT State: MD Zip Code: 20771 Country: USA Telephone: (301)-286-3625 Telex (or e-mail): LANDSMAN@STARS.GSFC.NASA.GOV ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5405 [ 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 HD204188 A, 120, 124, 128 RA = 21H 26M 26.67S +/- 2000 V = -12 1 V=6.07, TYPE = A8V, B-V = 0.24 HR8210 IK- 0.01S, 2 E(B-V) = 0.0 PEG DEC = 19D 22' 32.24" +/- 3 F(1855) = 5.0 +/- 0.1 E-12 0.1", 4 F(1210) = 2.0 +/- 0.2 E-13 5 F(1175) = 9.0 +/- 0.1 E-13 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J 2000.00 0.0058 +/- 0.0000 0.0180 +/- 0.0000 0.0000 +/- 0.0000 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5405 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 HD204188 HRS ACQ 2.0 MIRROR-A2 BRIGHT=RETURN 1 9S 1 1 CYCLE 4 PEAKUP=YES SEQ 10.0-14.0 NO GAP PERIOD 21.714896D +/- 0.0042D ZERO-PHASE Comments: STEP-TIME=1.0S EXPECT 1200 CTS JD2449070.08 +/- IN STEP-TIME RADIAL VELOCITY 0.003D PHASE 0.25 CONJUNCTION +/- 0.07 ONBOARD ACQ FOR 11 -14 ------------------------------------------------------------------------------------------------------------------------------------ 11 WAVE HRS ACCUM SC2 G160M 1210 1 60S 1 1 CYCLE 4 CALIB FOR 12.0 Comments: STANDARD SPECTRAL CAL LAMP SPECTRUM ------------------------------------------------------------------------------------------------------------------------------------ 12 HD204188 HRS ACCUM 2.0 G160M 1210 FP-SPLIT=STD 1 56M 16 4 1 CYCLE 4 56M Comments: BROAD LYMAN ALPHA ABSORPTION PROFILE ------------------------------------------------------------------------------------------------------------------------------------ 13 HD204188 HRS ACCUM 2.0 G160M 1175 FP-SPLIT=STD 1 25M 16 5 1 CYCLE 4 25M Comments: CENTER ON CIII 1175 ------------------------------------------------------------------------------------------------------------------------------------ 14 HD204188 HRS ACCUM 2.0 G160M 1855 FP-SPLIT=STD 1 3M 22 3 1 CYCLE 4 3M Comments: AL III 1855 ANGSTROMS ------------------------------------------------------------------------------------------------------------------------------------ 20 HD204188 HRS ACQ 2.0 MIRROR-A2 BRIGHT=RETURN 1 9S 1 1 CYCLE 4 PEAKUP=YES PHASE 0.00 +/- 0.1 OF REF 10.0 ONBOARD ACQ FOR 21 -23 SEQ 20.0-23.0 NO Comments: STEP_TME=1.0S EXPECT 1200 CTS GAP IN STEP-TIME ------------------------------------------------------------------------------------------------------------------------------------ 21 WAVE HRS ACCUM SC2 G160M 1210 1 60S 1 1 CYCLE 4 CALIB FOR 22.0 Comments: STANDARD SPECTRAL CAL LAMP SPECTRUM ------------------------------------------------------------------------------------------------------------------------------------ 22 HD204188 HRS ACCUM 2.0 G160M 1210 FP-SPLIT=STD 1 56M 16 4 1 CYCLE 4 56M Comments: BROAD LYMAN ALPHA ABSORPTION PROFILE ------------------------------------------------------------------------------------------------------------------------------------ 23 HD204188 HRS ACCUM 2.0 G160M 1855 FP-SPLIT=STD 1 3M 22 3 1 CYCLE 4 3M Comments: AL III 1855 ANGSTROMS ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5405 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 30 HD204188 HRS ACQ 2.0 MIRROR-A2 BRIGHT=RETURN 1 9S 1 1 CYCLE 4 PEAKUP=YES PHASE 0.50 +/- 0.1 OF REF 10.0 ONBOARD ACQ FOR 31 -33 SEQ 30.0-33.0 NO Comments: STEP_TME=1.0S EXPECT 1200 CTS GAP IN STEP-TIME ------------------------------------------------------------------------------------------------------------------------------------ 31 WAVE HRS ACCUM SC2 G160M 1210 1 60S 1 1 CYCLE 4 CALIB FOR 32.0 Comments: STANDARD SPECTRAL CAL LAMP SPECTRUM ------------------------------------------------------------------------------------------------------------------------------------ 32 HD204188 HRS ACCUM 2.0 G160M 1210 FP-SPLIT=STD 1 56M 16 4 1 CYCLE 4 56M Comments: BROAD LYMAN ALPHA ABSORPTION PROFILE ------------------------------------------------------------------------------------------------------------------------------------ 33 HD204188 HRS ACCUM 2.0 G160M 1855 FP-SPLIT=STD 1 3M 22 3 1 CYCLE 4 3M Comments: AL III 1855 ANGSTROMS ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5405 [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN PEAKUP=YES FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 6.17 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category WHITE DWARFS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4; SEQ 10.0-14.0 NO GAP; PERIOD 21.714896D +/- 0.0042D; ZERO-PHASE JD2449070.08 +/- 0.003D; PHASE 0.25 +/- 0.07; ONBOARD ACQ FOR 11-14; CALIB FOR 12.0; PHASE 0.00 +/- 0.1 OF REF 10.0; ONBOARD ACQ FOR 21-23; SEQ 20.0-23.0 NO GAP; CALIB FOR 22.0; PHASE 0.50 +/- 0.1 OF REF 10.0; ONBOARD ACQ FOR 31-33; SEQ 30.0-33.0 NO GAP; CALIB FOR 32.0; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-A2 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD204188 HR8210 IK-PEG ------------------------------------------------------------------------------------------------------------------------------------