5808( 0) - 07/18/95 18:03 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5808 Version: ********** Check-in Date: ********** 1.Proposal Title: Symbiotic Binaries: Nature of the Hot Components ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Hot Stars AR 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Mirek Plavec University of California, Los Angeles CoI: Charles Keyes Space Telescope Science Institute N CoI: Ivan Hubeny USRA, NASA Goddard Space Flight Center, N Greenbelt ------------------------------------------------------------------------------------ 6. Abstract We propose to rediscuss the existing HST observations of two symbiotic binaries, namely AG Pegasi and CI Cygni. These spectra were obviously taken for the purpose of studying the emission lines, typical for such systems; also, many spectra of AG Pegasi were obtained for calibration purposes. We propose to use this material primarily for an investigation of the continuous and absorption-line spectra, which should enable us to decide upon the nature of the hot components in these two binaries. This project parallels our own observing proposal, originally submitted for Cycle 3 and accepted by the TAC as supplemental (but not realized), and re- submitted now for Cycle 5 under the title ``Nature of the Hot Components of Symbiotic Binaries''. The spectra of AG Pegasi, taken for wavelength calibration, are of very good quality, and are usable for the study of the continuum and probably also of the absorption lines. We will attempt to extract as much information from all the existing spectra as we can for our modeling of the hot components. These can be either accreting white degenerate dwarfs, subdwarfs akin to the nuclei of planetary nebulae, or accretion disks surrounding non- degenerate low-mass stars. In the past, only indirect or insufficient clues have been used to resolve this question. We also plan to study the emission line profiles in order to understand their origin. We possess state-of-the-art modeling techniques for stellar atmospheres, accretion disks, and emission lines. ------------------------------------------------------------------------------------ Observations Description ------------------------ Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5808( 0) - 07/18/95 18:03 - [ 2] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5808( 0) - 07/18/95 18:03 - [ 3] Summary Form for Proposal 5808 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category AR ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Hot Stars ------------------------------------------------------------------------------------------------------------------------------------