6661( 9) - 06/28/96 14:50 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6661 Version: 9 Check-in Date: 28-Jun-1996 14:44:23 1.Proposal Title: UV Spectroscopy of face-on accretion disks ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle BINARIES AND STAR FOR GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: RICHARD WADE PENNSYLVANIA STATE UNIVERSITY CoI: Marcos Diaz Laboratorio Nacional de Astrofisica, N Brazil CoI: Ivan Hubeny NASA/Goddard Space Flight Center N CoI: Knox Long Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract We will obtain GHRS spectra at ~1 Angstrom\ resolution of three novalike variables that have low orbital inclinations, BD-7D3007 (= RW Sex), HD174107 (= V603 Aql), and MV-LYR. The blending and broadening of absorption lines from the accretion disk will not be as severe in these objects as in more edge-on systems, and we expect to see individual lines or blends that are distinctively characteristic of the varying projected velocities at different temperatures ( i.e. radii) in the disk. These aspects of the UV disk spectrum have not previously been used as a tool to study accretion disk physics. Comparison of line strengths with our detailed models will indicate whether it is necessary to consider irradiated or NLTE disks, and test in a new way whether the disks are in steady state. The shapes of lines that would be formed in the inner disk will tell whether the inner disk is actually present, an important check on observational and theoretical suggestions that the inner disk is missing in some cataclysmic variables. The improved understanding and characterization of the photospheric spectrum will aid in the analysis of the wind- formed P Cygni lines that are seen in these objects. We will use grating G140L, covering much of the mid-UV spectrum with S/N up to 200. ------------------------------------------------------------------------------------ 6661( 9) - 06/28/96 14:50 - [ 2] Observations Description ------------------------ We will observe three low-inclination cataclysmic variables, BD-7D3007 (=RW Sex), HD174107 (=V603 Aql), and MV-LYR, to study in detail the line spectrum and kinematically-broadened line profiles of their accretion disks. These are the brightest systems with low inclination, for which the orbital periods are known. We will obtain HRS spectra of each target using G140L. Table 1 gives basic information about the orbital period, orbital inclination, visibility window, and the predicted HRS count rate per diode at 1300 Angstrom using G140L in the LSA. (This is near the peak continuum rate for these stars, based on IUE low-dispersion data and the published sensitivity tables for HRS. For G140L/LSA, one resolution element ~eq 1.4 diode.) ----------------------------- --------------------- begintable begincenter begintabularlrrrrrr multicolumn7c Basic Data on Proposed Targets , Name& V Mag& CV Type & Period & Inclination & Visibility & Count Rate , & & & (hours)& (degrees) & (minutes) & (s^-1 diode^- 1), , RW Sex & 10.6 &NL/UX& 5.88& 34& 52& 67, V603 Aql& 11.7&NA & 3.31& 17& 52& 19, MV Lyr& 13.3&NL/VY& 3.20& 12& 55& 2.3, endtabular endcenter caption Count rate is quoted for 1300 Angstrom using GHRS + G140L/LSA. CV types are: NL-- Novalike, UX--UX UMa subclass, VY--VY Scl subclass, NA--slow nova. endtable --- ------------------------------------------------ We require high S/N data throughout much of the mid-UV, to sample lines formed at a broad range of effective temperatures in the disks. This requires two wavelength settings using G140L, covering 1150--1437 Angstrom and 1375--1662 Angstrom. The overlap of 54 Angstrom will be used to monitor the small variations in continuum flux level that are expected from one exposure to the next. In addition to sampling the most important diagnostic lines we will have a long enough wavelength baseline to fit simultaneously the overall UV energy distribution. The strongest lines in the IUE spectra of these stars are the resonance lines of C IV, Si IV, etc., which are partially formed in a wind. They are not directly useful for studying the disk photosphere; indeed, the disk photospheric spectrum must be understood before the wind profiles can be isolated. (The data collected on wind lines through this proposal will be studied by Co-I Long's postdoc, C. Knigge.) Our goal is to study the host of much weaker lines and blends, which make a pseudocontinuum with bumps and wiggles characteristic of a particular combination of white dwarf mass, mass accretion rate, and inclination, which will be different for each target. (See figures for examples of calculated line depths, often <5%.) For this reason we seek a S/N of 200 per diode near 1300 Angstrom and 1520 Angstrom (the latter region includes C I and Si II lines). In other parts of the spectrum the S/N will be below this by as much as a factor of 3. Our criterion will allow the confident detection of narrow structures with ~1-2% depth. The S/N goal is basically achievable for our two brighter targets, using 2 orbits for BD-7D3007 (RW Sex) and 4 orbits for HD174107 (V603 Aql). For our third target, MV-LYR, we must settle for S/N ~ 100 (short wavelengths) and 65 (long) in these regions, obtainable in 5 orbits, which should still allow a good basic analysis. Although we have listed our targets in priority order, it is important to study more than one of the targets, especially since HD174107 and MV-LYR are more nearly face-on. After target acquisition, we will fill each visibility period on each target with observations in both wavelength regions, so as to have interleaved observations to guard against undetected variability. Each observing period on a given wavelength setting will be divided into 108.8 intervals, to further explore the variability issue. There is an overlap region between our "red" and "blue" settings. The estimated total exposure time in the short and long regions is 600 s + 2220 s for BD-7D3007, 1800 s + 4860 s for HD174107, and 4700s + 4800 s for MV-LYR. We will use FP-SPLIT=STD to help achieve the high S/N desired. Because our original third target, MV-LYR, has gone into an extended faint state, we are substituting in its place the similar system BZ-CAM. The overall UV flux is similar but redder, and the exposure sequence has been modified slightly to compensate. Similar S/N is expected to result. Real Time Justification ----------------------- None. We will seek contemporaneous visual photometry and spectroscopy to confirm that our targets are in their normal, bright states. (Only MV-LYR has ever shown brightness levels significantly below its normal state, in the visible band, but these occurrences are quite rare.) These visible observations are not essential to the successful use of HST observations, but would possibly enhance interpretations of the HRS data. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6661( 9) - 06/28/96 14:50 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6661( 9) - 06/28/96 14:50 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 BD-7D3007 STAR,NOVA- RA=10H 19M 56.61S +/- 1",DEC=- J2000 V = 10.4+/-0.3 LIKE,ACCRETION 08D 41' 56.0" +/- 1.0",PLATE- F(1300)=3+/-0.5e-12 DISK,INTERACTING ID=0185 F(1520)=2.4+/-0.6e-12 BINARY, Comments: Coordinates from GSC, retrieved by R. Downes. 2 HD174107 STAR,CLASSICAL RA=18H 48M 54.61S +/- 1",DEC=00D J2000. V = 11.7+/-0.2 NOVA,ACCRETION 35' 03.0" +/- 1.0",PLATE-ID=050T F(1300)=1.15+/-0.1e-12 DISK,INTERACTING F(1520)=7.5+/-1.0e-13 BINARY, Comments: Coordinates from GSC, retrieved by R. Downes. 3 BZ-CAM STAR,NOVA- RA=06H 29M 33.95S +/- 1",DEC=71D J2000 V = 13.0+/-0.5 LIKE,ACCRETION 04' 37.1" +/- 1.0",PLATE-ID=00M8 F(1300)=1.5+/-0.5e-13 DISK,INTERACTING F(1520)=1.5+/-0.5e-13 BINARY, Comments: Coordinates are measured by R. Downes. UV flux varies somewhat, approx 1-sigma range indicated with error bars. 6661( 9) - 06/28/96 14:50 - [ 5] Visit: 01 Visit Requirements: BETWEEN 01-May-1996 AND 31-May-1996 On Hold Comments: Additional Comments: The between requirement is to allow for coordination with some ground observations in April. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 BD-7D3007 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,SEARCH-SIZE=3 1 9 S ONBOARD ACQ FOR 30-71 Comments: STEP-TIME=1S,expected acq count rate is 2000 per second. ------------------------------------------------------------------------------------------------------------------------------------ 30 BD-7D3007 HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 5 108.8 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 31 BD-7D3007 HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 5 108.8 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 50 BD-7D3007 HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 5 108.8 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 51 BD-7D3007 HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 5 108.8 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 70 BD-7D3007 HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 5 108.8 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 71 BD-7D3007 HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 4 108.8 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 6661( 9) - 06/28/96 14:50 - [ 6] Visit: 02 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 HD174107 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,SEARCH-SIZE=3 1 36 S ONBOARD ACQ FOR 20-90 Comments: STEP-TIME=4S, expected acq count rate is 800 per second ------------------------------------------------------------------------------------------------------------------------------------ 20 HD174107 HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 5 217.6 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 30 HD174107 HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 5 108.8 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 40 HD174107 HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 6 217.6 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 50 HD174107 HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 6 108.8 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 60 HD174107 HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 6 217.6 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 70 HD174107 HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 6 108.8 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 80 HD174107 HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 7 217.6 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 90 HD174107 HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 6 108.8 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 6661( 9) - 06/28/96 14:50 - [ 7] Visit: 03 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 BZ-CAM HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,SEARCH-SIZE=3, 1 56.25 S ONBOARD ACQ FOR 20-150 LOCATE=DEF Comments: STEP-TIME=6.25S, expected acq count rate is 100 per second ------------------------------------------------------------------------------------------------------------------------------------ 20 BZ-CAM HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 1 979.2 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 30 BZ-CAM HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 2 326.4 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 40 BZ-CAM HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 1 979.2 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 50 BZ-CAM HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 2 326.4 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 60 BZ-CAM HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 1 979.2 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 70 BZ-CAM HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 2 326.4 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 80 BZ-CAM HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 1 979.2 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 90 BZ-CAM HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 2 326.4 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 100 BZ-CAM HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 1 979.2 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 110 BZ-CAM HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 2 326.4 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 120 BZ-CAM HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 1 979.2 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 130 BZ-CAM HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 2 326.4 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 140 BZ-CAM HRS ACCUM 2.0 G140L 1375-16 FP-SPLIT=STD 1 979.2 S 62 ------------------------------------------------------------------------------------------------------------------------------------ 150 BZ-CAM HRS ACCUM 2.0 G140L 1150-14 FP-SPLIT=STD 2 326.4 S 37 ------------------------------------------------------------------------------------------------------------------------------------ 6661( 9) - 06/28/96 14:50 - [ 8] Summary Form for Proposal 6661 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=3 FP-SPLIT=STD LOCATE=DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category BINARIES AND STAR FORMATION ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 01-May-1996 AND 31-May-1996 ONBOARD ACQ FOR 30-71 ONBOARD ACQ FOR 20-90 ONBOARD ACQ FOR 20-150 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N1 G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names BD-7D3007 HD174107 BZ-CAM ------------------------------------------------------------------------------------------------------------------------------------