5872( 11) - 11/20/95 19:38 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5872 Version: 11 Check-in Date: ********** 1.Proposal Title: A Search for Light Elements in Quiescent X-Ray Nova ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Hot Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Chris Shrader NASA Goddard Space Flight Center CoI: Demosthenes Kazanas NASA Goddard Space Flight Center N ------------------------------------------------------------------------------------ 6. Abstract We propose near-UV spectroscopic observations using the GHRS in medium res. mode to search for the presence of light elements (Be, B) in a quiescent X-ray nova. The target selected is known, from ground-based high- res. spectroscopic studies, to contain anomalous abundances of Li. The motivation for this search is to test the hypothesis that nuclear spallation reactions, driven by hadronic flux from the compact objects, presumably occurring in an accretion torus about the compact object or in the atmosphere of the secondary, are responsible for the enhanced lithium abundance. Additionally, we will attempt to characterize the charged particle environments ambient to compact objects in these systems. This information could impact a number of astrophysical problems involving charged- particle induced non- thermal emission in the vicinity of compact objects. The relative abundances of Li, Be and B , since the Li can be produced by Alpha-Alpha process while the latter require CNO nuclei as spallation targets, can provide information characterizing the production environment. The confirmation of light element production in X-ray binaries could have broader implications regarding cosmic elemental abundances and primordial nucleosynthesis. HST is the only facility with the capability to carry out this research, as the strongest line features of Be and B are in the UV, and the spectral resolution and S/N requirements are well beyond the capabilities of any other current facility. ------------------------------------------------------------------------------------ 5872( 11) - 11/20/95 19:38 - [ 2] Observations Description ------------------------ We wish to observe the source with the GHRS G270M medium resolution first order grating. We have examined laboratory tables of the vacuum UV atomic line spectra in the regions adjacent to the lined of interest. It is our assessment that due to the presence of potentially contaminating weak line, mainly of Fe ions, that the resolution of the FOS would be inadequate for these measurements. The regions of interest include the BeI transitions at Lambda 2348Angstrom and Lambda 2495Angstrom, Lambda 2650Angstrom as well as BII and BI at Lambda 2395Angstrom, Lambda 3031Angstrom and Lambda 2497Angstrom, and LiI at Lambda 2741Angstrom. The UV continuum flux at Lambda 2400Angstrom is estimated to be approximately 0.30e-15 ergs/cm**2/sec/A, by scaling (factor of 100) from the measured (i.e. no reddening correction applied) outburst fluxes of Nova Muscae 1991 (Shrader and Gonzalez-Riestra 1993). That source had a color excess of E(B -V)=0.3, which intermediate to CenX-4; E(B-V)=0.2) and A0620 -00; E(B-V)=0.4. Using the sensitivity function tabulated in Table 8-2 of the GHRS Handbook, we have estimated the exposures required to achieve S/N 6-20 per diode are 9000 seconds for CenX-4. Real Time Justification ----------------------- None. None. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address: Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5872( 11) - 11/20/95 19:38 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 CenX-4 STAR, X-ray Novae RA = 14H 58M 21.90S +/- 0.08S, J2000 V = 0.0 V=18.0 DEC = -31D 40' 5.6" +/- 1.0", B-V=0.05 PLATE-ID = 02J0 Comments: Coordinates are from a cursor placement GASP measurement by Karla Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1979.314 0.0 0.0 0.0 5872( 11) - 11/20/95 19:38 - [ 4] Visit: 01 Visit Requirements: 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 CenX-4 FOS/BL ACQ/PEA 4.3 MIRROR SCAN-STEP- 1 15S ONBOARD ACQ FOR 2 K Y=1.23, SEARCH- SIZE-Y=3, SEARCH-SIZE-X=1 ------------------------------------------------------------------------------------------------------------------------------------ 2 CenX-4 FOS/BL ACQ/PEA 1.0 MIRROR SCAN-STEP- 1 15S ONBOARD ACQ FOR 3 K Y=0.61, SCAN- STEP-X=0.61, SEARCH-SIZE- Y=2, SEARCH- Comments: SIZE-X=6 ------------------------------------------------------------------------------------------------------------------------------------ 3 CenX-4 FOS/BL ACQ/PEA 0.5 MIRROR SCAN-STEP- 1 30S ONBOARD ACQ FOR 4-7 K Y=0.29, SCAN- STEP-X=0.29, SEARCH-SIZE- Y=3, SEARCH- Comments: SIZE-X=3 ------------------------------------------------------------------------------------------------------------------------------------ 4 CenX-4 HRS ACCUM 2.0 G270M 2348 STEP- 6 1196.8S TIME=0.2,STEP- PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5 CenX-4 HRS ACCUM 2.0 G270M 2348 STEP- 6 1196.8S TIME=0.2,STEP- PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 6 CenX-4 HRS ACCUM 2.0 G270M 2348 STEP- 6 1196.8S TIME=0.2,STEP- PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 7 CenX-4 HRS ACCUM 2.0 G270M 3130 STEP- 7 1224S PATT=DEF,STEP- TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 5872( 11) - 11/20/95 19:38 - [ 5] Summary Form for Proposal 5872 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SCAN-STEP-Y=1.23 SEARCH-SIZE-Y=3 SEARCH-SIZE-X=1 SEARCH-SIZE-X=6 SEARCH-SIZE-X=3 STEP-PATT=DEF STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Hot Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 4-7 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G270M ------------------------------------------------------------------------------------------------------------------------------------ Target Names CenX-4 ------------------------------------------------------------------------------------------------------------------------------------