6615( 7) - 11/12/96 11:46 - [ 0] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6615 Version: 7 Check-in Date: 12-Nov-1996 11:32:09 1.Proposal Title: Fundamental Parameters of White Dwarfs in Close Binaries with Late-Type Stars ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle HOT STARS GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: STEPHANE VENNES UC BERKELEY CoI: Prof. John R. Thorstensen Dartmouth College, Department of Physics N and Astronomy CoI: Elisha Polomski University of Florida, Astronomy N Department ------------------------------------------------------------------------------------ 6. Abstract White dwarfs in close binaries, in a degenerate pair or with a main sequence companion, emerge from a common envelope phase, concomitant with the passage of the most evolved component through the asymptotic giant branch. The properties of the present-day binary are dictated by the efficiency of the momentum transfer leading to orbital shrinkage and mass ejection from the system (PN). Little is known of this process. Three new close binaries similar to the prototypical system Feige 24 (P=4.2d) consisting of a hot white dwarf star and a late-type companion (dM) have been identified in extreme ultraviolet all-sky surveys (EUVE J0720-317, EUVE J1016- 053, EUVE J2013+400); these objects may represent a dominant phase of white dwarf evolution. We have completed accurate radial velocity studies of the main sequence companion in the three new systems using echelle spectroscopy at Lick Observatory from which we derived accurate orbital ephemerides and mass functions. Extreme Ultraviolet Explorer spectroscopy of the system EUVE J1016-053 also revealed a peculiar abundance pattern in the white dwarf atmosphere, possibly the signature of intense accretion from the close mass-losing companion. We show that GHRS observations will solve the question of the peculiar surface abundance of the accreting white dwarf and also accurately solve the mass function of the system and constrain models of close binary evolution. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose to make spectroscopic observations at wavelengths of 1550 and 1640 Angstroms of 4 white dwarf stars in binary systems and to measure orbital velocities at 2 different orbital phases. Because the binary orbital periods are on the order of a few hours, the observations must be constrained to within one, or at the most two orbits to minimize the effects of blurring in velocity. This also limits the S/N to between 18 and 22 (in the following Table, 1st orbital phase refers to phi=0.75 and 2nd orbital phase to phi=0.25). Wavelength calibrations are needed to determine the wavelength zero point accurately and subsequently calculate velocities. A WAVECAL is performed for each new exposure. A WAVECAL allows wavelength zero points to be determined to within 0.2 diodes. In order to minimize blurring in velocity, as a Special Requirement each WAVECAL must precede the ACCUM exposure to which it applies and must not be split from its group of ACCUM exposures. For the G160M grating, this allows wavelengths to be determined to within .0144 angstrosm at worst. At 1550 angstroms this reduces the uncertainty in velocity from approximately 15 km/s (or a relative accuracy of 15% assuming a typical orbital velocity of 100 km/s) down to 3 km/s (3% accuracy). Object Name Wavelength Flux Exposure S/N Orbits (angstroms) (erg cm-2 s-1 angs-1) (min) Feige 24(1st phase) 1550 25e-13 10 25 1/2 Feige 24(1st phase) 1640 20e-13 11 23 1/2 Feige 24(2nd phase) 1550 25e-13 10 25 1/2 Feige 24(2nd phase) 1640 20e-13 11 23 1/2 0720-317(1st phase) 1550 4.3e-13 60 25 2 0720-317(1st phase) 1640 3.6e-13 74 25 2 0720-317(2nd phase) 1640 3.6e-13 67 24 2 1016-053(1st phase) 1550 8.1e-13 28 24 1 1016-053(1st phase) 1640 6.8e-13 39 25 1 1016-053(2nd phase) 1640 6.8e-13 28 21 1 2013+400(1st phase) 1550 8.1e-13 30 24 1 2013+400(1st phase) 1640 6.8e-13 41 25 1 2013+400(2nd phase) 1640 6.8e-13 30 22 1 An example of a typical exposure calculation follows: EUVE 1016-053 has a flux at 1550 angstroms(from IUE) of 8.1e-13 erg cm-2 s-1 angstroms-1. Neither scattered light nor dark count are important for our purposes. Keeping in mind that the maximum S/N attainable in our configuration is approximately 30, and the constraint of fitting the entire exposure within one orbit, we were able to obtain 20 minutes of exposure. Using the instrument sensitivity S(1550)=4.05e11 cts diode-1 s-1, exposure time in seconds, and assuming n(s)=1, one obtains the S/N from the following formula: (S/N)^2 = s*n(s)*t; t=1200 secs; s=F(1550)*S(1550); n(s)=1 S/N=19.8 In Figure 4 we show a synthetic He II(1640) line profile at two typical velocities, 0 km/s and +100 km/s relative to the rest frame, with Poisson-added noise. The effective temperature, surface gravity and helium abundance are typical of the systems EUVE J0720-317 and 1016-053. Real Time Justification ----------------------- To maximize the relative accuracy of the measurement of the primary orbital velocity amplitude, we suggest to conduct the observations near binary orbital quadratures. The ephemeris of each system is known to sufficient accuracy to provide accurate scheduling in the forecoming decade. However, it is sufficient to schedule each visit using the spacecraft orbit nearest to the desired binary phase. With orbital periods ranging from 17 hours to 4 days, scheduling opportunities arise regularly on corresponding intervals of time. Accurate ephemeris and orbital motion for the secondary have been determined prior to the proposed HST observations. Calibration Justification ------------------------- Wavelength calibrations are needed to determine the wavelength zero point accurately and subsequently calculate velocities. A WAVECAL is performed for each new exposure. A WAVECAL allows wavelength zero points to be determined to within 0.2 diodes. In order to minimize blurring in velocity, as a Special Requirement each WAVECAL must precede the ACCUM exposure to which it applies and must not be split from its group of ACCUM exposures. For the G160M grating, this allows wavelengths to be determined to within .0144 angstroms at worst. At 1550 angstroms this reduces the uncertainty in velocity from approximately 15 km/s (or a relative accuracy of 15% assuming a typical orbital velocity of 100 km/s) down to 3 km/s (3% accuracy). Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6615( 7) - 11/12/96 11:46 - [ 1] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 WD0232+035 STAR,DA RA=02H 35M 07.51S +/-0.02S, J2000 V = 12.42+/-0.01 DEC=+03D 43' 56.6" +/-0.3", B-V = -0.24+/-0.01 PLATE-ID=002M F(1550)=25.0+/-2.5e-13 F(1640)=20+/-2.0e-13 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1982.882 0.005 0.00 0.0 2 EUVE-J0720- STAR,DA RA=07H 20M 47.87S +/- 0.02S, J2000 V = 14.77+/-0.04 317 DEC=-31D 47' 03.4" +/- 0.3", B-V = -0.10+/-0.05 PLATE-ID=0164 F(1550)=4.3+/-0.43e-13 F(1640)=3.6+/-0.36e-13 Comments: Epoch1994 imaging shows no significant PM relative to DSS. 3 EUVE-J1016- STAR,DA RA=10H 16M 28.60S +/-.02S, DEC=- J2000 V = 14.15+/-0.03 053 05D 20' 35.6" +/- 0.3", PLATE- B-V = -0.18+/-0.04 ID=03W1 F(1550)=8.1+/-0.81e-13 F(1640)=6.8+/-0.68e-13 Comments: Crowded star is 3.2" NE. The GSC centroid for the pair (GSC_04910_01132) is 10 16 28.71 -05 20 34.1 and epoch1994 imaging places EUVE J1016-053 some 2" SW. 4 EUVE- STAR,DA RA=20H 13M 09.31S +/- 0.02S, J2000 V = 14.2+/-0.1 J2013+400 DEC=+40D 02' 24.12" +/- 0.3", B-V = -0.15+/-0.05 PLATE-ID=003S F(1550)=8.1+/-0.81e-13 F(1640)=6.8+/-0.68e-13 Comments: Epoch1994 imaging shows no significant PM relative to DSS. 6615( 7) - 11/12/96 11:46 - [ 2] Visit: 01 Visit Requirements: PERIOD 4.23160D AND ZERO-PHASE JD2448578.397 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 WD0232+035 HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 2-5 PHASE 0.15 TO 0.25 SEQ 1-5 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G160M 1550 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 3 WD0232+035 HRS ACCUM 2.0 G160M 1550 1 707.2 S ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 5 WD0232+035 HRS ACCUM 2.0 G160M 1640 1 707.2 S ------------------------------------------------------------------------------------------------------------------------------------ 6615( 7) - 11/12/96 11:46 - [ 3] Visit: 02 Visit Requirements: PERIOD 4.23160D AND ZERO-PHASE JD2448578.397 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 WD0232+035 HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 2-5 PHASE 0.65 TO 0.75 SEQ 1-5 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G160M 1550 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 3 WD0232+035 HRS ACCUM 2.0 G160M 1550 1 707.2 S ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 5 WD0232+035 HRS ACCUM 2.0 G160M 1640 1 707.2 S ------------------------------------------------------------------------------------------------------------------------------------ 6615( 7) - 11/12/96 11:46 - [ 4] Visit: 03 Visit Requirements: PERIOD 1.26245D AND ZERO-PHASE JD2449735.327 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EUVE-J0720- HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 2-12 317 PHASE 0.15 TO 0.25 SEQ 1-3 NON-INT Comments: With 0.2S Step Time Expect 338 counts ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G160M 1550 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 3 EUVE-J0720- HRS ACCUM 2.0 G160M 1550 3 571.2 S 317 ------------------------------------------------------------------------------------------------------------------------------------ 6 WAVE HRS ACCUM SC2 G160M 1550 1 54.4 S SEQ 6-7 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 7 EUVE-J0720- HRS ACCUM 2.0 G160M 1550 4 598.4 S 317 ------------------------------------------------------------------------------------------------------------------------------------ 9 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S SEQ 9-10 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 10 EUVE-J0720- HRS ACCUM 2.0 G160M 1640 4 598.4 S 317 ------------------------------------------------------------------------------------------------------------------------------------ 11 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S SEQ 11-12 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 12 EUVE-J0720- HRS ACCUM 2.0 G160M 1640 4 598.4 S 317 ------------------------------------------------------------------------------------------------------------------------------------ 6615( 7) - 11/12/96 11:46 - [ 5] Visit: 04 Visit Requirements: PERIOD 1.26245D AND ZERO-PHASE JD2449735.327 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EUVE-J0720- HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 2-6 PHASE 317 0.65 TO 0.75 SEQ 1-3 NON-INT Comments: With 0.2S Step-TIME expect 338 counts ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 3 EUVE-J0720- HRS ACCUM 2.0 G160M 1640 3 571.2 S 317 ------------------------------------------------------------------------------------------------------------------------------------ 5 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S SEQ 5-6 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 6 EUVE-J0720- HRS ACCUM 2.0 G160M 1640 4 598.4 S 317 ------------------------------------------------------------------------------------------------------------------------------------ 6615( 7) - 11/12/96 11:46 - [ 6] Visit: 05 Visit Requirements: PERIOD 0.78929D AND ZERO-PHASE JD2449771.3493 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EUVE-J1016- HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 2-7 PHASE 053 0.15 TO 0.25 SEQ 1-3 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G160M 1550 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 3 EUVE-J1016- HRS ACCUM 2.0 G160M 1550 3 544.0 S 053 ------------------------------------------------------------------------------------------------------------------------------------ 5 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S SEQ 5-7 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 6 EUVE-J1016- HRS ACCUM 2.0 G160M 1640 3 598.4 S 053 ------------------------------------------------------------------------------------------------------------------------------------ 7 EUVE-J1016- HRS ACCUM 2.0 G160M 1640 1 544.0 S 053 ------------------------------------------------------------------------------------------------------------------------------------ 6615( 7) - 11/12/96 11:46 - [ 7] Visit: 06 Visit Requirements: PERIOD 0.78929D AND ZERO-PHASE JD2449771.3493 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EUVE-J1016- HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 2-3 PHASE 053 0.65 TO 0.75 SEQ 1-3 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 3 EUVE-J1016- HRS ACCUM 2.0 G160M 1640 3 544.0 S 053 ------------------------------------------------------------------------------------------------------------------------------------ 6615( 7) - 11/12/96 11:46 - [ 8] Visit: 07 Visit Requirements: PERIOD 0.705516D AND ZERO-PHASE JD2449586.6612 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EUVE-J2013+ HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 2-7 PHASE 400 0.15 TO 0.25 SEQ 1-3 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G160M 1550 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 3 EUVE-J2013+ HRS ACCUM 2.0 G160M 1550 3 598.4 S 400 ------------------------------------------------------------------------------------------------------------------------------------ 5 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S SEQ 5-7 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 6 EUVE-J2013+ HRS ACCUM 2.0 G160M 1640 2 598.4 S 400 ------------------------------------------------------------------------------------------------------------------------------------ 7 EUVE-J2013+ HRS ACCUM 2.0 G160M 1640 2 625.6 S 400 ------------------------------------------------------------------------------------------------------------------------------------ 6615( 7) - 11/12/96 11:46 - [ 9] Visit: 08 Visit Requirements: PERIOD 0.705516D AND ZERO-PHASE JD2449586.6612 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EUVE-J2013+ HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 2-3 PHASE 400 0.65 TO 0.75 SEQ 1-3 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 3 EUVE-J2013+ HRS ACCUM 2.0 G160M 1640 3 598.4 S 400 ------------------------------------------------------------------------------------------------------------------------------------ 6615( 7) - 11/12/96 11:46 - [ 10] Visit: 57 Visit Requirements: PERIOD 0.705516D AND ZERO-PHASE JD2449586.6612 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EUVE-J2013+ HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 2-7 PHASE 400 0.15 TO 0.25 SEQ 1-3 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G160M 1550 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 3 EUVE-J2013+ HRS ACCUM 2.0 G160M 1550 3 598.4 S 400 ------------------------------------------------------------------------------------------------------------------------------------ 5 WAVE HRS ACCUM SC2 G160M 1640 1 54.4 S SEQ 5-7 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 6 EUVE-J2013+ HRS ACCUM 2.0 G160M 1640 2 598.4 S 400 ------------------------------------------------------------------------------------------------------------------------------------ 7 EUVE-J2013+ HRS ACCUM 2.0 G160M 1640 2 625.6 S 400 ------------------------------------------------------------------------------------------------------------------------------------ 6615( 7) - 11/12/96 11:46 - [ 11] Summary Form for Proposal 6615 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PERIOD 4.23160D AND ZERO-PHASE JD2448578.397 ONBOARD ACQ FOR 2-5 PHASE 0.15 TO 0.25 SEQ 1-5 NON-INT ONBOARD ACQ FOR 2-5 PHASE 0.65 TO 0.75 SEQ 1-5 NON-INT PERIOD 1.26245D AND ZERO-PHASE JD2449735.327 ONBOARD ACQ FOR 2-12 PHASE 0.15 TO 0.25 SEQ 1-3 NON-INT SEQ 6-7 NON-INT SEQ 9-10 NON-INT SEQ 11-12 NON-INT ONBOARD ACQ FOR 2-6 PHASE 0.65 TO 0.75 SEQ 1-3 NON-INT SEQ 5-6 NON-INT PERIOD 0.78929D AND ZERO-PHASE JD2449771.3493 ONBOARD ACQ FOR 2-7 PHASE 0.15 TO 0.25 SEQ 1-3 NON-INT SEQ 5-7 NON-INT ONBOARD ACQ FOR 2-3 PHASE 0.65 TO 0.75 SEQ 1-3 NON-INT PERIOD 0.705516D AND ZERO-PHASE JD2449586.6612 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names WD0232+035 WAVE EUVE-J0720-317 EUVE-J1016-053 EUVE-J2013+400 ------------------------------------------------------------------------------------------------------------------------------------