8308( 5) - 05/26/99 10:49 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8308 Version: 5 Check-in Date: 26-May-1999 10:48:24 1.Proposal Title: The FUV Spectrum of SS 433 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Douglas Gies Georgia State University CoI: Dr. William Bagnuolo Jr. Georgia State University N ------------------------------------------------------------------------------------ 5. Abstract We propose to make the first ever investigation of the FUV spectrum of the unusual X -ray binary, SS 433, using STIS and its sensitive MAMA detector. The unexplored FUV region should offer significant clues about the nature of the mass- losing star and mass loss by winds. Our plan is to obtain spectra at key phases in the disk precessional cycle in order to document the spectral variations associated with this ``clock''. We will use a tomography algorithm to separate the FUV spectral features associated with the moving jets and the "stationary" disk and star components, and we will compare the optical and FUV light curves to establish the flux contributions from the various parts of this system. We will search for the UV P Cygni profiles associated with winds to test if colliding winds are a source of the X-ray flux. The huge redshifts associated with the jets will translate jet flux from the Lyman limit into the region near Ly-alpha, and these variations will help elucidat e the radiative processes that dri ve the jets. The proposed observations offer an exceptional opportunity to study the mass loss processes at this singular stage in binary star evolution. ------------------------------------------------------------------------------------ 8308( 5) - 05/26/99 10:49 - [ 2] Observations Description ------------------------ We propose to make spectra of SS 433 with the G140L first order grating which records the FUV spectrum over the range 1150 to 1730 Angstrom with an average dispersion of 0.6 Angstrom per pixel (R=1000). The resolution will be degraded somewhat through the use of the 52X2 slit which will provide the maximum throughput and spectrophotometric accuracy (needed for FUV light curves of the system). There are two sources of information on the FUV flux of SS 433. The single IUE, low dispersion, SWP spectrum available (SWP05398) shows a weak spectrum (continuum or groups of emission lines) with a mean flux of 1.9*10^-16 erg cm^-2 s^-1 Angstrom^-1 around 1600 Angstroms. Dolan et al. (1997, A&A, 327, 648) observed SS 433 with the High Speed Photometer aboard HST, and they report a mean flux of 7.8 micro-Jy or 1.1*10^-16 erg cm^-2 s^-1 Angstrom^-1 in 1400 - 3000 Angstrom range. We used these two limits with the WWW STIS Exposure Calculator to determine the expected counts and sign al to noise ratios for the propose d spectra. We assumed that the FUV spectrum looks similar to an O5 star (Kurucz model fluxes) reddened by E(B-V)=2.6 which we normalized to the two flux limits given above. We then used the WWW STIS Exposure Calculator to find the S/N per resolution element for a cumulative exposure time of 120 minutes (the total available in 3 orbits after subtraction of 7 minutes for guide star acquisition, 6 minutes for reacquisition in the second orbit, 6 minutes for target acquisition, 8 minutes for MAMA overhead, and 1 minute for repeated spectra). We also assumed average levels for zodiacal light and earthshine. This calculation indicates a final S/N per resolution element of 6 to 9 for the flux limits given above, i.e., comparable to that of slightly under-exposed IUE spectra. We expect that this S/N noise ratio will be acceptable for our science goals since most of the spectral features of interest are predicted to be broad and strong. If the spectrum does contain strong emiss ion lines, then the S/N recor ded in these features will be better than given above. The STIS calculator predicts that best exposed part of the spectrum will be in the range 1300 to 1700 Angstroms which is ideal for recording the C IV 1550 wind feature. Based on our knowledge of the optical spectral variations, we expect that the FUV spectral features will vary with the 162.15 day precessional period and the 13.087 day orbital period. Because the target is faint in the FUV, we will restrict the observations to out-of-eclipse orbital phases, and we will concentrate on variations that occur through the precessional cycle. Our plan is to obtain five spectra of SS 433 at approximately one month intervals to follow the radial velocity and flux variations through one precessional cycle in order to determine the differential changes in the spectrum caused by the changing orientation of the disk and jets. While the orbital ephemeris is stable, the precessional ephemeris is not, and we will obtain contempora neous optical spectra to document the jet radial velocity curves at the times of the HST observations. The tomography algorithm will use these velocity curves to reconstruct three spectral components: the red and blue jet systems and the "stationary" spectrum. We will need a minimum of 5 visits (of 3 orbits each) at differing points in the radial velocity curves to reconstruct faithfully these three spectral components. Real Time Justification ----------------------- (a) The system fades by about 1 magnitude in the visual (and probably more in the UV) during eclipse, and since the target is faint to begin with, we need to avoid the eclipse phases. This is the reason for the PHASE restriction. (b) The precessional (jet) cycle (162.15 d) is not strictly predictable, and therefore we are planning to obtain near simultaneous ground-based spectroscopy to determine the radial velocity curve independently. (We need to know the velocity behavior to properly analyze the STIS spectra.) Thus we need to observe the target when it is also visible from the ground (April - October). Since this range of months falls more fully in 1999 than 2000 during Cycle 8, we are requesting observations in 1999 using the BETWEEN special requirement. (c) The 5 visits need to be spread over about 0.8 of the precessional cycle in order to guarantee coverage of the full range of radial velocity variations (the key element of the science analysis), and so we have block ed the visits into five, non-overl apping, 21 day windows covering 0.8 of a single precessional cycle. (d) The dates for the first visit are centered on the time of an already scheduled run at the KPNO Coude Feed Telescope (25 JUN 1999 - 9 JUL 1999). This offers a good chance to obtain near simultaneous ground-based spectroscopy. We will be applying for other runs at KPNO and McDonald Observatory to overlap with the other HST visits. The BETWEEN dates are calculated starting with KPNO run and the subsequent visits are each separated by approximately 0.2 of the precessional cycle (about one month). The greatest radial velocity separation of the jet components is predicted to occur during Visit 04. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8308( 5) - 05/26/99 10:49 - [ 3] Data Distribution Paper Products: YES Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8308( 5) - 05/26/99 10:49 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V1343-AQL STAR, Interacting RA=19H 11M 49.60S +/- 0.05S, J2000 Z = 0.04 V = 14.3+/-0.9 Binary, Emission Line DEC=04D 58' 57.9" +/- 0.2", B-V = 2.1+/-0.2 Star PLATE-ID=00ZZ E(B-V) = 2.6+/-0.2 F-CONT(1600)=1.9+/-0.8e-16 Comments: Coordinates are from GSC Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1982.565 0.0 0.0 0.0 8308( 5) - 05/26/99 10:49 - [ 5] Visit: 01 Visit Priority: Visit Requirements: PERIOD 13.08211 D AND ZERO-PHASE JD2450023.620000 BETWEEN 21-Jun-1999 AND 12-Jul-1999 SCHED 80% 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 V1343-AQL STIS/C ACQ F28X50L MIRROR 1 0.5 S ONBOARD ACQ FOR 2-3 PHASE CD P 0.15 TO 0.85 ------------------------------------------------------------------------------------------------------------------------------------ 2 V1343-AQL STIS/F ACCUM 52X2 G140L 1425 1 27 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 V1343-AQL STIS/F ACCUM 52X2 G140L 1425 2 42 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8308( 5) - 05/26/99 10:49 - [ 6] Visit: 02 Visit Priority: Visit Requirements: PERIOD 13.08211 D AND ZERO-PHASE JD2450023.620000 BETWEEN 25-Jul-1999 AND 14-Aug-1999 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 V1343-AQL STIS/C ACQ F28X50L MIRROR 1 0.5 S ONBOARD ACQ FOR 2-3 PHASE CD P 0.15 TO 0.85 ------------------------------------------------------------------------------------------------------------------------------------ 2 V1343-AQL STIS/F ACCUM 52X2 G140L 1425 1 27 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 V1343-AQL STIS/F ACCUM 52X2 G140L 1425 2 42 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8308( 5) - 05/26/99 10:49 - [ 7] Visit: 03 Visit Priority: Visit Requirements: PERIOD 13.08211 D AND ZERO-PHASE JD2450023.620000 BETWEEN 26-Aug-1999 AND 15-Sep-1999 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 V1343-AQL STIS/C ACQ F28X50L MIRROR 1 0.5 S ONBOARD ACQ FOR 2-3 PHASE CD P 0.15 TO 0.85 ------------------------------------------------------------------------------------------------------------------------------------ 2 V1343-AQL STIS/F ACCUM 52X2 G140L 1425 1 27 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 V1343-AQL STIS/F ACCUM 52X2 G140L 1425 2 42 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8308( 5) - 05/26/99 10:49 - [ 8] Visit: 04 Visit Priority: Visit Requirements: PERIOD 13.08211 D AND ZERO-PHASE JD2450023.620000 BETWEEN 28-Sep-1999 AND 18-Oct-1999 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 V1343-AQL STIS/C ACQ F28X50L MIRROR 1 0.5 S ONBOARD ACQ FOR 2-3 PHASE CD P 0.15 TO 0.85 ------------------------------------------------------------------------------------------------------------------------------------ 2 V1343-AQL STIS/F ACCUM 52X2 G140L 1425 1 27 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 V1343-AQL STIS/F ACCUM 52X2 G140L 1425 2 42 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8308( 5) - 05/26/99 10:49 - [ 9] Visit: 05 Visit Priority: Visit Requirements: PERIOD 13.08211 D AND ZERO-PHASE JD2450023.620000 BETWEEN 30-Oct-1999 AND 19-Nov-1999 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 V1343-AQL STIS/C ACQ F28X50L MIRROR 1 0.5 S ONBOARD ACQ FOR 2-3 PHASE CD P 0.15 TO 0.85 ------------------------------------------------------------------------------------------------------------------------------------ 2 V1343-AQL STIS/F ACCUM 52X2 G140L 1425 1 27 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 V1343-AQL STIS/F ACCUM 52X2 G140L 1425 2 42 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8308( 5) - 05/26/99 10:49 - [ 10] Summary Form for Proposal 8308 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PERIOD 13.08211 D AND ZERO-PHASE JD2450023.620000 BETWEEN 21-Jun-1999 AND 12-Jul-1999 SCHED 80% ONBOARD ACQ FOR 2-3 PHASE 0.15 TO 0.85 PERIOD 13.08211 D AND ZERO-PHASE JD2450023.620000 BETWEEN 25-Jul-1999 AND 14-Aug-1999 PERIOD 13.08211 D AND ZERO-PHASE JD2450023.620000 BETWEEN 26-Aug-1999 AND 15-Sep-1999 PERIOD 13.08211 D AND ZERO-PHASE JD2450023.620000 BETWEEN 28-Sep-1999 AND 18-Oct-1999 PERIOD 13.08211 D AND ZERO-PHASE JD2450023.620000 BETWEEN 30-Oct-1999 AND 19-Nov-1999 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names V1343-AQL ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 ------------------------------------------------------------------------------------------------------------------------------------