5861( 4) - 07/27/95 13:44 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5861 Version: 4 Check-in Date: ********** 1.Proposal Title: The boron abundance of tidally locked binaries in the Hyades cluster ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Cool Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Fabio Favata European Space Agency, Astrophysics Division CoI: Giuseppina Micela Osservatorio Astronomico di Palermo ``G.S. N Vaiana'' CoI: Salvatore Sciortino Osservatorio Astronomico di Palermo ``G.S. N Vaiana'' ------------------------------------------------------------------------------------ 6. Abstract We propose to measure the boron abundance in two short period, tidally locked binaries in the Hyades clusters, which all exhibit higher lithium abundance than Hyades stars of comparable mass and effective temperature. This observed higher lithium abundance is in agreement with the predictions of rotating stellar models combined with tidal synchronization theory. The same rotating stellar models are however at loss explaining the spread of lithium abundance in younger open clusters. We will observe the short period binaries together with two single stars also from the Hyades, as close as possible in effective temperature to the targets. This will provide an immediate comparison sample to check whether locked binaries are also enriched in boron. ------------------------------------------------------------------------------------ 5861( 4) - 07/27/95 13:44 - [ 2] Observations Description ------------------------ The spectral region around the boron I doublet at 2497 Angstrom will be observer using the G270M grating, thus obtaining a resolution of about 24000, at a signal to noise ratio of at least 80 per pixel. The obtained spectra will be analyzed by comparing them with synthetic spectra obtained using appropriate model atmospheres and assuming a range of boron abundances. Although the resolution attainable with the Echelle B would be desirable, the efficiency is much lower, and exposure times would thus become too long. The feasibility of measuring B abundances by using the G270M grating has already been demonstrated, for example by Duncan et al. (1992, ApJ, 401, 584). To compute the required observing time we have used Kurucz model atmospheres of the appropriate effective temperature and of solar metallicity (appropriate for the young stars which constitute our sample), scaling them to the visual magnitude appropriate for each object in the sample. The resulting incident source spectrum has been convolved through the total HST response obtaining the expected count rate per pixel. The count rate was then used to estimate the time required to obtain a signal to noise ratio of at least 80. Name B-V V N(Li) orbits SNR comments HD30738 0.504 7.29 3.13 2 >= 80 Tidally locked binary, HD28394 0.502 7.05 2.35 2 >= 80 comparison for HD30738 HD28033 0.537 7.38 3.36 3 >= 80 Tidally locked binary HD28205 0.535 7.42 3.17 3 >= 80 comparison for HD28033 Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5861( 4) - 07/27/95 13:44 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD30738 STAR, F3-F9 RA=4H 50M 48.54S +/- 0.01S, J2000 V = +40 V = 7.29 DEC=16D 12' 37.4" +/- 0.1" B-V = 0.50 TYPE = F8V F(2500) = 4.5E-13 Comments: Coordinates are from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 0.0059 -0.024 0.040 2 HD28394 STAR, F3-F9 RA=4H 29M 20.54S +/- 0.01S, J2000 V = +35 V = 7.04 B-V = 0.50 TYPE = F7V F(2500) = DEC=17D 32' 41.5" +/- 0.1" 5.7E-13 Comments: Coordinates are from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 0.0069 -0.027 0.040 3 HD28033 STAR, G V-IV RA=4H 26M 18.49S +/- 0.01S, J2000 V = +42 V = 7.38 B-V = 0.54 TYPE = F8V F(2500) = DEC=21D 28' 13.5" +/- 0.1" 3.7E-13 Comments: Coordinates are from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 0.0065 -0.034 0.040 4 HD28205 STAR, G V-IV RA=4H 27M 35.9S +/- 0.01S, J2000 V = +39 V = 7.42 B-V = 0.54 TYPE = G0V F(2500) = DEC=15D 35' 20.9" +/- 0.1" 3.6E-13 Comments: Coordinates are from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 0.0071 -0.027 0.040 5861( 4) - 07/27/95 13:44 - [ 4] Visit: 01 Visit Requirements: PCS MODE F 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 HD30738 HRS ACQ 2.0 MIRROR-N2 BRIGHT = RETURN 1 1.8S ONBOARD ACQ FOR 2 Comments: STEP-TIME = 0.2S (yielding approx 17000 cts/step), SEARCH-SIZE = 3 (default) ------------------------------------------------------------------------------------------------------------------------------------ 2 HD30738 HRS ACCUM 2.0 G270M 2497 FP-SPLIT = STD 3 1414.4S DOPPLER = DEF STEP-PATT = DEF Comments: Long (4.3 ks, i.e. 2 orbits) exposure broken up into several 5 min exposures. FP-SPLIT=4 means that 1200S exp actually is 4 300S exp. S/N should be about 90 ------------------------------------------------------------------------------------------------------------------------------------ 5861( 4) - 07/27/95 13:44 - [ 5] Visit: 02 Visit Requirements: PCS MODE F 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 HD28394 HRS ACQ 2.0 MIRROR-N2 BRIGHT = RETURN 1 1.8S ONBOARD ACQ FOR 2 Comments: STEP-TIME = 0.2 (yielding approx 20000 cts/step), SEARCH-SIZE = 3 (default) ------------------------------------------------------------------------------------------------------------------------------------ 2 HD28394 HRS ACCUM 2.0 G270M 2497 FP-SPLIT = STD 3 1414.4S DOPPLER = DEF STEP-PATT = DEF Comments: Long (4.3 ks, i.e. 2 orbits) exposure broken up into several 5 min exposures. FP-SPLIT=4 means that 1200S exp actually is 4 300S exp. S/N should be about 90 ------------------------------------------------------------------------------------------------------------------------------------ 5861( 4) - 07/27/95 13:44 - [ 6] Visit: 03 Visit Requirements: PCS MODE F 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 HD28033 HRS ACQ 2.0 MIRROR-N2 BRIGHT = RETURN 1 1.8S ONBOARD ACQ FOR 2 Comments: STEP-TIME = 0.2 (yielding approx 16000 cts/step), SEARCH-SIZE = 3 (default) ------------------------------------------------------------------------------------------------------------------------------------ 2 HD28033 HRS ACCUM 2.0 G270M 2497 FP-SPLIT = STD 5 1414.4S DOPPLER = DEF STEP-PATT = DEF Comments: Long (7.1 ks, i.e. 3 orbits) exposure broken up into several 5 min exposures. S/N should be about 100 ------------------------------------------------------------------------------------------------------------------------------------ 5861( 4) - 07/27/95 13:44 - [ 7] Visit: 04 Visit Requirements: PCS MODE F 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 HD28205 HRS ACQ 2.0 MIRROR-N2 BRIGHT = RETURN 1 1.8S ONBOARD ACQ FOR 2 Comments: STEP-TIME = 0.2 (yielding approx 15000 cts/step), SEARCH-SIZE = 3 (default) ------------------------------------------------------------------------------------------------------------------------------------ 2 HD28205 HRS ACCUM 2.0 G270M 2497 FP-SPLIT = STD 5 1414.4S DOPPLER = DEF STEP-PATT = DEF Comments: Long (7.1 ks, i.e. 3 orbits) exposure broken up into several 5 min exposures. S/N should be about 90 ------------------------------------------------------------------------------------------------------------------------------------ 5861( 4) - 07/27/95 13:44 - [ 8] Summary Form for Proposal 5861 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT = RETURN FP-SPLIT = STD DOPPLER = DEF STEP-PATT = DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE F ONBOARD ACQ FOR 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G270M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD30738 HD28394 HD28033 HD28205 ------------------------------------------------------------------------------------------------------------------------------------