Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5610 Report Date: 18-Jul-95:17:44 Version: ********** Check-in Date: ********** 1.Proposal Title: SYMBIOTIC SYSTEMS IN THE MAGELLANIC CLOUDS CYCLE 4 HIGH ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID HOT STARS GO/DD Sub Category ERUPTIVE BINARIES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Manfred Vogel ETH ZURICH SWITZERLAN ------------------------------------------------------------------------------------ 7. Abstract We propose FOS observations of symbiotic systems in the Magellanic Clouds. The goal of this proposal is twofold : (1) The main goal is an accurate determination of the luminosity and radiation temperature of the hot component in symbiotic systems. That knowledge is of prime importance when trying to situate symbiotics in an evolutionary scenario. Since distances to galactic symbiotics are very badly known, observations in the Magellanic Clouds can be the basis for a breakthrough. (2) From the nebular spectrum we can fairly easily determine relative CNO abundances of symbiotic nebulae. As the nebula has its origin in the red giant, this provides a straightforward method for determining relative C/N/O abundances of the Magellanic red giants without the uncertainties of a stellar atmosphere analysis. Up to now almost all information about the chemistry of the Clouds has been derived from H II regions and planetary nebulae. The proposed observations present therefore also a new possibility for studying abundances in the Magellanic Clouds. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 4.20 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5610 PI: Manfred Vogel Proposal Title: SYMBIOTIC SYSTEMS IN THE MAGELLANIC CLOUDS CYCLE 4 HIGH ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Manfred Vogel ETH ZURICH SWITZERLAND X Harry Nussbaumer ETH ZURICH SWITZERLAND X Steven N. Shore COMPUTER SCIENCES CORPORATION USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. For determining the radiation temperature and luminosity of the hot component we need to observe the He II 1640 line and the continuum to wavelengths as short as possible. As these observations do not require high resolution, we plan for each target one exposure with the G130H grating, observed in the 4.3 arcsec aperture. As a side benefit we obtain at the shortest HST wavelengths some of the most interesting nebular emission lines like N V 1240, the dielectronic recombination line O V 1371 and the multiplet Si IV 1401. They give additional information on the ionization state of these objects. For abundance determinations we need absolute fluxes of the CNO lines in the UV: C III] 1908, C IV 1550, N III] 1750, N IV] 1486, and O III] 1664. In addition to the G130H observation for the temperature and luminosity determination, one complementary exposure with the G190H grating will provide the C III] 1908 line. Thus, two exposures for every target would then cover the range from 1150 to 2300 A, and contain all the crucial emission lines as well as a sufficiently broad fraction of the stellar and nebular continuum to determine the shape of the continuous energy distribution. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. By their very nature symbiotics demand observations in the far UV. The hot components have radiation temperatures of at least 50000 K, but mostly of 100000 K and higher. Contrary to other classes of double star systems, the hot components are only directly observable at the shortest wavelengths accessible with HST. On the other hand, the luminous M giant which dominates the visual and the infrared, makes essentially no contribution in the far UV. IUE provided a tremendous boost to research of galactic symbiotics. However, the limited sensitivity and the low dynamic range of IUE prevented anything beyond an exploratory study of symbiotic systems in the Magellanic Clouds in the UV. The FOS on HST is very well suited for an extension of research to extragalactic symbiotics. There is at present no substitute for the dynamic range required by our proposal and provided by HST. In addition, since the hot components in symbiotic systems are only directly observable at wavelengths shorter than 1600 A, the FOS is the most suited instrument for the proposed scientific goal, and there is obviously no ground-based substitute. Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. S 63-LMC is reasonably well observed with IUE to estimate absolute fluxes in the UV. We use this star as a reference and scale the exposure times for the targets with unknown UV fluxes according to their blue or visual magnitudes. The visual magnitude of S 63 is V = 15.6, and the ultraviolet flux is approximately 1E-14 erg/cm/cm/sec/Ang at 1500 A. The strength of the three emission lines C III] 1908, N III] 1750, and O III] 1664 which are in the G190H range is between 3E-14 and 4E-14 erg/cm/cm/sec, and the line width we estimate to be approximately 2 A. The exposure times for S 63 are calculated as follows : the calibration curve of the FOS/BL (Gilliland and Hartig 1991) yield for G130H at 1500 A about 1E+13 cts/diode/sec per erg/cm/cm/sec/A, and the sensitivity of G190H is about 2E+13 cts/diode/sec per erg/cm/cm/sec/A at 1640 A, and higher for longer wavelengths. For a S/N = 10 in the continuum this requires an integration time of 1000 sec using the G130H grating in order to obtain the energy distribution of the hot object. For the He II 1640 equivalent width and the emission lines of C III] 1908, N III] 1750, and O III] 1664 an integration time of 300 sec will provide a S/N of about 10 in the emission lines and in the He II 1640 equivalent width. All exposures will be taken through the 4.3 arcsec aperture. The total exposure time for S 63 would therefore be approx. 22 min. The exposure times for Ln 358 are calculated assuming that it has about the same spectral distribution as S 63, and that the exposure times will simply scale with the V magnitude. The indivudual exposure times are chosen to tune the the total spacecraft to the allocated 4.2 hours. The total number of targets is 2, the total number of visits is also 2, and the total number of exposures is 4. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. None ------------------------------------------------------------------------------------ 8. Additional comments or special requests. None. ------------------------------------------------------------------------------------ 9. Description of previous HST work. Nr. 2342 - The symbiotic phenomenon. (Michalitsianos, Fahey, Kafatos, Nussbaumer, Paresce) The observations have not yet been done. The goal of that project, which will concentrate on the symbiotic star R Aqr (which is not a symbiotic nova), is not related to the purpose of this proposal. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). At ETH (Swiss Federal Institute of Technology) we have excellent computer facilities which we can access directly from our institute, e.g. Cray YMP, VAX 9000. Allocation of requested computer access and time has never been a problem. In addition we have several computer work stations as part of the infrastructure of our institute. From ETH and the Swiss Science Foundation we have always received grants for two to three Ph.D. students to work on these projects, in addition two post-doctoral positions have been granted to work on HST related projects. Travel money needed is included in the budget of our institute. Cray YMP time will also be available at GSFC. SPAN links between institutions will permit rapid exchange of, and analysis of, the HST data. ------------------------------------------------------------------------------------ 11. Address Information Name: MANFRED VOGEL Category: PI Institution: ETH Zurich Address: ETH ZENTRUM City: 8092 ZURICH State: Zip Code: Country: SWITZERLAND Telephone: 41-1-632 3806 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5610 [ 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 S63 A,155 RA = 05H 48M 43.2S +/- 2000 1 V = 14.7 0.1S, DEC = -67D 36' 09.1" +/- 1" ------------------------------------------------------------------------------------------------------------------------------------ 5 LN358 A,155 RA = 00H 59M 12.4S +/- 2000 1 V = 15.0 0.1S, DEC = -75D 05' 17.2" +/- 1" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5610 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 3 S63 FOS/BL ACQ/ 4.3 MIRROR SEARCH-SIZE-X=1 1 10S 1 3 ONBOARD ACQ FOR 4 PEAK SEARCH-SIZE-Y=3 CYCLE 4 / 3-18 SCAN-STEP- Y=1.204 Comments: COARSE PEAK-UP IN 4.3 ------------------------------------------------------------------------------------------------------------------------------------ 4 S63 FOS/BL ACQ/ 1.0 MIRROR SEARCH-SIZE-X=6 1 10S 1 3 ONBOARD ACQ FOR 5- PEAK SEARCH-SIZE-Y=2 6 SCAN-STEP- X=.602 SCAN-STEP- Y=.602 Comments: FINE PEAK-UP IN 1.0 ------------------------------------------------------------------------------------------------------------------------------------ 5 S63 FOS/BL ACCUM 4.3 G130H 1 25M 10 1 3 ------------------------------------------------------------------------------------------------------------------------------------ 6 S63 FOS/BL ACCUM 4.3 G190H 1 15M 10 1 3 ------------------------------------------------------------------------------------------------------------------------------------ 15 LN358 FOS/BL ACQ/ 4.3 MIRROR SEARCH-SIZE-X=1 1 10S 1 1 ONBOARD ACQ FOR 16 PEAK SEARCH-SIZE-Y=3 SCAN-STEP- Y=1.204 Comments: COARSE PEAK-UP IN 4.3 ------------------------------------------------------------------------------------------------------------------------------------ 16 LN358 FOS/BL ACQ/ 1.0 MIRROR SEARCH-SIZE-X=6 1 10S 1 1 ONBOARD ACQ FOR 17 PEAK SEARCH-SIZE-Y=2 -18 SCAN-STEP- X=.602 SCAN-STEP- Y=.602 Comments: FINE PEAK-UP IN 1.0 ------------------------------------------------------------------------------------------------------------------------------------ 17 LN358 FOS/BL ACCUM 4.3 G130H 1 30M 10 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 18 LN358 FOS/BL ACCUM 4.3 G190H 1 20M 10 1 1 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5610 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP-Y=1.204 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP-X=.602 SCAN-STEP-Y=.602 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO/DD ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 4.20 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ERUPTIVE BINARIES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 4; CYCLE 4 / 3-18 ONBOARD ACQ FOR 5-6 ONBOARD ACQ FOR 16 ONBOARD ACQ FOR 17-18 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G130H G190H ------------------------------------------------------------------------------------------------------------------------------------ Target Names S63 LN358 ------------------------------------------------------------------------------------------------------------------------------------