Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 2634c Report Date: 09-May-96:17:16 Version: ********** Check-in Date: ********** 1.Proposal Title: B AND BE AS PROBES OF COSMIC RAY SPALLATION AND STELLAR STRUCTURE ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR ASTROPHYSICS GO Sub Category STELLAR ATMOSPHERES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. Douglas K. Duncan STSCI USA 301-338-4935 HRS INSTR. SCIENTIST ------------------------------------------------------------------------------------ 7. Abstract I. We propose to observe Boron and Beryllium in one intermediate metallicity halo stars ([Fe/H]~-1.5) which appears to have formed at the time when the galaxy was just beginning to syntheize those two light elements through the spallation reactions of cosmic rays on C,N,O nuclei in the interstellar medium. The B and Be abundances and their ratio yield knowledge of the energetic particle flux at this epoch and on the time of formation of the halo, in the same way that the current interstellar medium light element abundances are used to constrain theories of present cosmic rays. II. We propose to observe B in two stars in the "Li gap," the mysterious narrow temperature range in F stars in which Li is depleted by more than an order of magnitude compared to stars just a few 100 K hotter or cooler. Knowledge of whether B is depleted in the same star should help decide whether turbulent diffusion, gravitational settling, or some other as yet unknown mixing process is responsible for the gap. ------------------------------------------------------------------------------------ 8. Scientific Key Words: DWARF, POPULATION II, COSMIC RAYS, HALO, STELLAR STRUCTURE, OPEN CLUSTER ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 4.20 par: 0 10. Num targs pri: 5 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 2634c PI: Dr. Douglas K. Duncan Proposal Title: B AND BE AS PROBES OF COSMIC RAY SPALLATION AND STELLAR STRUCTURE ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Dr. David R. Soderblom STSCI USA P.I. Douglas K. Duncan STSCI USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. Observations will be standard ACCUM mode GHRS spectra, using G270, SSA and ECH- B, LSA settings. Resolution will be about .03-.1 angstrom, S/N 45, adequate for spectum synthesis work. To assure adequate S/N, FP/SPLIT will be used. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The B I line at 2498 ang. is not observable from the ground. The Be II line at 3130 ang. is only very marginally observable. A 5300 sec. exposure on a 4-m. telescope allowed an abundance measurement with error of 250 per cent. Since the present purpose is to derive the Be/B ratio as a test of cosmic ray models of the early galaxy, we need a much better measurement. That is why an HST spectrum is needed for the two halo stars. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. All long wavelength, low-res. IUE exposures ever taken of very metal poor and intermediate metal-poor stars were examined, as well as ones of a number of solar -metallicity stars. A grid was constructed of flux at 2500 ang. and 3130 ang. as a function of stellar temperature and metallicity, for stars with U mag. = 0. For each star, interpolation was made according to temp. and metal abundance, and fluxes scaled according to U magnitude. This computation, has now been updated mid-April, 1991 with the newest sensitivity curves and should be quite good. The S/N reached will only be 40-50, rather than 70, but should still be adequate. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. None. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Initial reduction will be done at STScI by Duncan and Soderblom, using STSDAS, of course. Dave Lambert, an Observatory Scientist and GTO, has invited us to combine our observations with simlar ones he is doing with his GTO time, and to do the analysis together. All three of us have experience with spectrum synthesis. This work could be done either at the Univ. of Texas or at STScI. The eventual interpretation of the abundances in terms of theoretical models (e.g. gravitational settling) is more involved. Two groups, Michaud et al in Canada, and Vauclair et al in France perform such calculations. The calculations for B and Be in this temperature range have not yet been done, though with current interest they may be expected. One of us (DD) has an invitation to work with the French group on this problem. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Normal access to STScI facilities. Only 7 spectra will be produced. Reduction will be under STSDAS. ------------------------------------------------------------------------------------ 11. Address Information Page 3 Name: DOUGLAS K. DUNCAN Category: PI Institution: SPACE TELESCOPE SCIENCE INSTITUTE Address: 3700 SAN MARTIN DRIVE City: BALTIMORE State: MD Zip Code: 21218 Country: USA Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 2634c [ 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 HD84937 STAR; SUBDWARF RA = 09H 46M 12.283S +/- J1950 1 V = 8.32 0.06S, 2 B-V = 0.37 +/- 0.02,U-B = -0.20 +/ DEC = +13D 59' 10.3" +/- 3 - 0.03 1.0" 4 F(3130) = 1.3 +/- 0.3 E-12 F(2500) = 0.86 +/- 0.1 E-12 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J 1959.23 0.0241 +/- 0.0010 -0.7690 +/- 0.0150 0.1000 +/- 0.0500 ------------------------------------------------------------------------------------------------------------------------------------ 2 VB13 STAR; OPEN CLUSTER RA = 4H 10M 42.22S +/- J2000 1 V = 6.62 0.06S, 2 B-V = 0.43 +/- 0.01,U-B = -0.01 +/ DEC = 18D 25' 24.2" +/- 1.0" 3 - 0.02 4 F(3130) = 4.8 +/- 0.8 E-12 F(2500) = 0.79 +/- 0.25 E-12 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J 1983.00 0.0079 +/- 0.0007 -0.0350 +/- 0.0080 0.1000 +/- 0.0500 ------------------------------------------------------------------------------------------------------------------------------------ 3 VB14 STAR; OPEN CLUSTER RA = 4H 11M 20.08S +/- J2000 1 V = 5.72 0.06S, 2 B-V = 0.36 +/- 0.01,U-B = 0.00 +/- DEC = 5D 31' 22.9" +/- 1.0" 3 0.02 4 F(3130) = 1.2 +/- 0.3 E-11 F(2500) = 2.2 +/- 0.6 E-12 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J 1982.90 0.0089 +/- 0.0007 0.0090 +/- 0.0100 0.1000 +/- 0.0500 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2634c [ 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 HD84937 HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=5 1 2.5S 3 1 ONBOARD ACQ FOR 2 FAINT=5000 4 CYCLE 1 / 1-10 ------------------------------------------------------------------------------------------------------------------------------------ 2 HD84937 HRS ACCUM 2.0 ECH-B 3130 FP-SPLIT=STD 2 2160S 40 3 1 STEP-PATT=7 4000S ------------------------------------------------------------------------------------------------------------------------------------ 3 HD84937 HRS ACQ/ 2.0 MIRROR-N2 1 9.2S 1 1 ONBOARD ACQ FOR 4 PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ 4 HD84937 HRS ACCUM 0.25 G270M 2498 FP-SPLIT=STD 2 2000S 60 4 1 STEP-PATT=5 4000S ------------------------------------------------------------------------------------------------------------------------------------ 5 VB13 HRS ACQ 2.0 MIRROR-A2 SEARCH-SIZE=3 1 9S 3 1 ONBOARD ACQ FOR 6 FAINT=500 4 ------------------------------------------------------------------------------------------------------------------------------------ 6 VB13 HRS ACQ/ 2.0 MIRROR-A2 1 46S 1 1 ONBOARD ACQ FOR 7 PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ 7 VB13 HRS ACCUM 0.25 G270M 2498 FP-SPLIT=STD 1 2300S 50 3 1 STEP-PATT=5 2300S 4 ------------------------------------------------------------------------------------------------------------------------------------ 8 VB14 HRS ACQ 2.0 MIRROR-A2 SEARCH-SIZE=3 1 3.6S 3 1 ONBOARD ACQ FOR 9 FAINT=500 4 ------------------------------------------------------------------------------------------------------------------------------------ 9 VB14 HRS ACQ/ 2.0 MIRROR-A2 1 18.4S 1 1 ONBOARD ACQ FOR 10 PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ 10 VB14 HRS ACCUM 0.25 G270M 2498 FP-SPLIT=STD 1 1080S 50 3 1 STEP-PATT=5 1080S 4 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 2634c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ACQ/PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE=5 FAINT=5000 FP-SPLIT=STD STEP-PATT=7 STEP-PATT=5 SEARCH-SIZE=3 FAINT=500 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 4.20 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR ASTROPHYSICS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category STELLAR ATMOSPHERES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2; CYCLE 1 / 1-10 ONBOARD ACQ FOR 4 ONBOARD ACQ FOR 6 ONBOARD ACQ FOR 7 ONBOARD ACQ FOR 9 ONBOARD ACQ FOR 10 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 ECH-B G270M MIRROR-A2 ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD84937 VB13 VB14 ------------------------------------------------------------------------------------------------------------------------------------