6089( 3) - 01/17/96 10:58 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6089 Version: 3 Check-in Date: 17-Jan-1996 10:48:49 1.Proposal Title: 14 Aur C - New Insight into Late Stages of Close Binary Evolution ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Hot Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Ronald F. Webbink University of Illinois CoI: Edward F. Guinan Villanova University Y CoI: Paul B. Etzel San Diego State University N ------------------------------------------------------------------------------------ 6. Abstract 14 Aur C is a short-period spectroscopic binary consisting of an F3V primary and a hot DA white dwarf companion which is visible only in the ultraviolet. It is the only example known of a close binary main sequence-white dwarf pair in which the main sequence star spectral classification is earlier than G. Two widely-accepted evolutionary scenarios lead to objects of this type: Common envelope evolution in a channel paralleling cataclysmic variable (CV) formation, or quasi-conservative (Algol-type) evolution. Available observational constraints lead to serious inconsistencies with each of these scenarios if the white dwarf component is assumed to lie upon predicted cooling curves appropriate to its mass. Evidently, either (1) the white dwarf is not actually the close companion to the F3V primary, but a chance superposition or a third component in an unresolved triple; (2) one of the evolutionary scenarios contains a fundamental flaw not heretofore recognized; or (3) the white dwarf has a much more extended photosphere than cooling curves predict. A dynamical mass determination for the white dwarf is essential to sorting out this discrepancy, and possible only with HST ultraviolet Lyman-alpha spectroscopy. Confirmation is also needed for incipient Fe V absorption lines suggested in IUE spectra; if present, they may arise in the white dwarf photosphere, providing a superior mass estimate and photospheric abundance determination. ------------------------------------------------------------------------------------ 6089( 3) - 01/17/96 10:58 - [ 2] Observations Description ------------------------ Medium-resolution spectra centered at 1216A (Lyman-alpha) and 1370A (Fe V complex) are to be obtained at each of six orbital phases of 14 Aur C. Lyman- alpha spectra are to be used to determine the radial velocities (orbital semi- amplitude and gravitational redshift) of the hot DA white dwarf in this binary. Wavelength calibration of these spectra is required to ensure reliable velocity measures near Lyman-alpha (Section 4.5 of the GHRS Instrument Handbook). Spectra centered at 1370A are to be used to search for Fe V lines suggested in IUE spectra. If these lines are present, they may also be used to extract radial velocities; standard pipeline reductions should be adequate in this spectral window. Real Time Justification ----------------------- Visits have been scheduled into phase windows in the 3-day orbit of 14Aur-C to ensure adequate phase distribution of the observations for an orbital determination of this star. Each of these phase windows span several HST orbits, except for Visit 5, which is timed to superior conjuction of the white dwarf component of this binary (the UV source under observation). In this one case, an eclipse of the UV source is possible, if it lies at the lower extreme of its allowed mass range. In that event, HST target acquisition will probably fail, but detection of such an eclipse would be of pivotal importance to modeling this binary. Calibration Justification ------------------------- Wavelength calibration of the Lyman-alpha spectra is required to ensure reliable velocities from this feature. Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: Edward F. Guinan*Astronomy Department*Villanova University*Villanova, PA 19085 Ship Via: UPS Email: guinan@ucis.vill.edu , ------------------------------------------------------------------------------------ 6089( 3) - 01/17/96 10:58 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 14AUR-C STAR, COMPOSITE RA=05H 15M 23.51S +/- 0.024S, 2000 V=-6.73 V = 7.896+/-0.023 SPECTRAL TYPE, F3-F9, DEC=+32D 41' 04.7" +/- 0.30" TYPE=F3V+DA DA B-V = +0.41+/-0.015 F-CONT(1206)=1.12+/-0.05e-12 F-CONT(1213)=0.60+/-0.08e-12 F-CONT(1215)=0.28+/-0.09e-12 F-CONT(1217)=0.32+/-0.06e-12 F-CONT(1219)=0.65+/-0.06e-12 F-CONT(1226)=1.10+/-0.03e-12 Comments: GSC position, quoted, is adopted from the Hipparcos F-CONT(1370)=1.07+/-0.01e-12 Input Catalogue, which is calculated for Epoch J2000. Lyman-alpha absorption line spans the entire spectral window centered at 1216 A. F-CONT values in 1206-1226 A range represent the mean profile observed with IUE. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 -0.0032 0.008 0.011 6089( 3) - 01/17/96 10:58 - [ 4] Visit: 01 Visit Requirements: PERIOD 2.9932564D AND ZERO-PHASE JD2448883.8478 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 14AUR-C HRS ACQ 2.0 MIRROR-N1 1 22.5S ONBOARD ACQ FOR 3 Comments: STEP-TIME=2.5S; EXPECT 3125 COUNTS in STEP- TIME ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G140M 1216 1 DEF Comments: WAVE/CAL FOR LY-ALPHA SPECTROSCOPY ------------------------------------------------------------------------------------------------------------------------------------ 3 14AUR-C HRS ACCUM 2.0 G140M 1216 FP-SPLIT=STD 1 326.4S PHASE 0.7 TO 0.9 Comments: LY-ALPHA CORE ------------------------------------------------------------------------------------------------------------------------------------ 4 14AUR-C HRS ACCUM 2.0 G140M 1370 FP-SPLIT=STD 1 435.2S Comments: FE V COMPLEX ------------------------------------------------------------------------------------------------------------------------------------ 6089( 3) - 01/17/96 10:58 - [ 5] Visit: 02 Visit Requirements: PERIOD 2.9932564D AND ZERO-PHASE JD2448883.8478 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 14AUR-C HRS ACQ 2.0 MIRROR-N1 1 22.5S ONBOARD ACQ FOR 3 Comments: STEP-TIME=2.5S; EXPECT 3125 COUNTS in STEP- TIME ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G140M 1216 1 DEF Comments: WAVE/CAL FOR LY-ALPHA SPECTROSCOPY ------------------------------------------------------------------------------------------------------------------------------------ 3 14AUR-C HRS ACCUM 2.0 G140M 1216 FP-SPLIT=STD 1 326.4S PHASE 0.2 TO 0.4 Comments: LY-ALPHA CORE ------------------------------------------------------------------------------------------------------------------------------------ 4 14AUR-C HRS ACCUM 2.0 G140M 1370 FP-SPLIT=STD 1 435.2S Comments: FE V COMPLEX ------------------------------------------------------------------------------------------------------------------------------------ 6089( 3) - 01/17/96 10:58 - [ 6] Visit: 03 Visit Requirements: PERIOD 2.9932564D AND ZERO-PHASE JD2448883.8478 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 14AUR-C HRS ACQ 2.0 MIRROR-N1 1 22.5S ONBOARD ACQ FOR 3 Comments: STEP-TIME=2.5S; EXPECT 3125 COUNTS in STEP- TIME ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G140M 1216 1 DEF Comments: WAVE/CAL FOR LY-ALPHA SPECTROSCOPY ------------------------------------------------------------------------------------------------------------------------------------ 3 14AUR-C HRS ACCUM 2.0 G140M 1216 FP-SPLIT=STD 1 326.4S PHASE 0.65 TO 0.95 Comments: LY-ALPHA CORE ------------------------------------------------------------------------------------------------------------------------------------ 4 14AUR-C HRS ACCUM 2.0 G140M 1370 FP-SPLIT=STD 1 435.2S Comments: FE V COMPLEX ------------------------------------------------------------------------------------------------------------------------------------ 6089( 3) - 01/17/96 10:58 - [ 7] Visit: 04 Visit Requirements: PERIOD 2.9932564D AND ZERO-PHASE JD2448883.8478 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 14AUR-C HRS ACQ 2.0 MIRROR-N1 1 22.5S ONBOARD ACQ FOR 3 Comments: STEP-TIME=2.5S; EXPECT 3125 COUNTS in STEP- TIME ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G140M 1216 1 DEF Comments: WAVE/CAL FOR LY-ALPHA SPECTROSCOPY ------------------------------------------------------------------------------------------------------------------------------------ 3 14AUR-C HRS ACCUM 2.0 G140M 1216 FP-SPLIT=STD 1 326.4S PHASE 0.15 TO 0.45 ------------------------------------------------------------------------------------------------------------------------------------ 4 14AUR-C HRS ACCUM 2.0 G140M 1370 FP-SPLIT=STD 1 435.2S Comments: FE V COMPLEX ------------------------------------------------------------------------------------------------------------------------------------ 6089( 3) - 01/17/96 10:58 - [ 8] Visit: 05 Visit Requirements: PERIOD 2.9932564D AND ZERO-PHASE JD2448883.8478 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 14AUR-C HRS ACQ 2.0 MIRROR-N1 1 22.5S ONBOARD ACQ FOR 3 Comments: STEP-TIME=2.5S; SMALL, BUT NONZERO POSSIBILITY THAT TARGET WILL BE IN ECLIPSE AT THIS PHASE, IN WHICH CASE ACQUISITION WILL FAIL; OTHERWISE, EXPECT 3125 COUNTS IN STEP- TIME ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G140M 1216 1 DEF Comments: WAVE/CAL FOR LY-ALPHA SPECTROSCOPY ------------------------------------------------------------------------------------------------------------------------------------ 3 14AUR-C HRS ACCUM 2.0 G140M 1216 FP-SPLIT=STD 1 326.4S PHASE 0.040 TO 0.055 ------------------------------------------------------------------------------------------------------------------------------------ 4 14AUR-C HRS ACCUM 2.0 G140M 1370 FP-SPLIT=STD 1 435.2S Comments: FE V COMPLEX ------------------------------------------------------------------------------------------------------------------------------------ 6089( 3) - 01/17/96 10:58 - [ 9] Visit: 06 Visit Requirements: PERIOD 2.9932564D AND ZERO-PHASE JD2448883.8478 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 14AUR-C HRS ACQ 2.0 MIRROR-N1 1 22.5S ONBOARD ACQ FOR 3 Comments: STEP-TIME=2.5S; EXPECT 3125 COUNTS in STEP- TIME ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G140M 1216 1 DEF Comments: WAVE/CAL FOR LY-ALPHA SPECTROSCOPY ------------------------------------------------------------------------------------------------------------------------------------ 3 14AUR-C HRS ACCUM 2.0 G140M 1216 FP-SPLIT=STD 1 326.4S PHASE 0.45 TO 0.65 ------------------------------------------------------------------------------------------------------------------------------------ 4 14AUR-C HRS ACCUM 2.0 G140M 1370 FP-SPLIT=STD 1 435.2S ------------------------------------------------------------------------------------------------------------------------------------ 6089( 3) - 01/17/96 10:58 - [ 10] Summary Form for Proposal 6089 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Hot Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PERIOD 2.9932564D AND ZERO-PHASE JD2448883.8478 ONBOARD ACQ FOR 3 PHASE 0.7 TO 0.9 PHASE 0.2 TO 0.4 PHASE 0.65 TO 0.95 PHASE 0.15 TO 0.45 PHASE 0.040 TO 0.055 PHASE 0.45 TO 0.65 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N1 G140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names 14AUR-C WAVE ------------------------------------------------------------------------------------------------------------------------------------