! $Id: 6661,v 9.1 1996/06/28 18:44:19 pepsa Exp $ Proposal_Information Title: UV Spectroscopy of face-on accretion disks Proposal_Category: GO Scientific_Category: BINARIES AND STAR FORMATION Cycle: 6 Investigators PI_Name: Richard Wade PI_Institution: The Pennsylvania State University CoI_Name: Marcos Diaz CoI_Institution: Laboratorio Nacional de Astrofisica, Brazil Contact: CoI_Name: Ivan Hubeny CoI_Institution: NASA/Goddard Space Flight Center Contact: CoI_Name: Knox Long CoI_Institution: Space Telescope Science Institute Contact: 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. Questions Observing_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: Fixed_Targets Target_Number: 1 Target_Name: BD-7D3007 Alternate_Names: GSC5490-556,RW-SEX Description: STAR,NOVA-LIKE,ACCRETION DISK,INTERACTING BINARY, Position: RA=10H 19M 56.61S +/- 1",DEC=-08D 41' 56.0" +/- 1.0",PLATE-ID=0185 Equinox: J2000 RV_or_Z: RA_PM: Dec_PM: Epoch: Annual_Parallax: Flux: V = 10.4+/-0.3 F(1300)=3+/-0.5e-12 F(1520)=2.4+/-0.6e-12 Comments: Coordinates from GSC, retrieved by R. Downes. Target_Number: 2 Target_Name: HD174107 Alternate_Names: GSC0448-423,V603-AQL Description: STAR,CLASSICAL NOVA,ACCRETION DISK,INTERACTING BINARY, Position: RA=18H 48M 54.61S +/- 1",DEC=00D 35' 03.0" +/- 1.0",PLATE-ID=050T Equinox: J2000. RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 11.7+/-0.2 F(1300)=1.15+/-0.1e-12 F(1520)=7.5+/-1.0e-13 Comments: Coordinates from GSC, retrieved by R. Downes. Target_Number: 3 Target_Name: BZ-CAM Alternate_Names: Description: STAR,NOVA-LIKE,ACCRETION DISK,INTERACTING BINARY, Position: RA=06H 29M 33.95S +/- 1",DEC=71D 04' 37.1" +/- 1.0",PLATE-ID=00M8 Equinox: J2000 RV_or_Z: RA_PM: Dec_PM: Epoch: Annual_Parallax: Flux: V = 13.0+/-0.5 F(1300)=1.5+/-0.5e-13 F(1520)=1.5+/-0.5e-13 Comments: Coordinates are measured by R. Downes. UV flux varies somewhat, approx 1-sigma range indicated with error bars. Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: BETWEEN 01-May-1996 AND 31-May-1996 On_Hold_Comments: Visit_Comments: The between requirement is to allow for coordination with some ground observations in April. Exposure_Number: 10 Target_Name: BD-7D3007 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: BRIGHT=RETURN,SEARCH-SIZE=3 Number_of_Iterations: 1 Time_Per_Exposure: 9S Special_Requirements: ONBOARD ACQ FOR 30-71 Comments: STEP-TIME=1S,expected acq count rate is 2000 per second. Exposure_Number: 30 Target_Name: BD-7D3007 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 5 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 31 Target_Name: BD-7D3007 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 5 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 50 Target_Name: BD-7D3007 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 5 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 51 Target_Name: BD-7D3007 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 5 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 70 Target_Name: BD-7D3007 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 5 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 71 Target_Name: BD-7D3007 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 4 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Visit_Number: 02 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: HD174107 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: BRIGHT=RETURN,SEARCH-SIZE=3 Number_of_Iterations: 1 Time_Per_Exposure: 36S Special_Requirements: ONBOARD ACQ FOR 20-90 Comments: STEP-TIME=4S, expected acq count rate is 800 per second Exposure_Number: 20 Target_Name: HD174107 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 5 Time_Per_Exposure: 217.6S Special_Requirements: Comments: Exposure_Number: 30 Target_Name: HD174107 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 5 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 40 Target_Name: HD174107 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 6 Time_Per_Exposure: 217.6S Special_Requirements: Comments: Exposure_Number: 50 Target_Name: HD174107 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 6 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 60 Target_Name: HD174107 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 6 Time_Per_Exposure: 217.6S Special_Requirements: Comments: Exposure_Number: 70 Target_Name: HD174107 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 6 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 80 Target_Name: HD174107 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 7 Time_Per_Exposure: 217.6S Special_Requirements: Comments: Exposure_Number: 90 Target_Name: HD174107 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 6 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Visit_Number: 03 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: BZ-CAM Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: BRIGHT=RETURN,SEARCH-SIZE=3,LOCATE=DEF Number_of_Iterations: 1 Time_Per_Exposure: 56.25S Special_Requirements: ONBOARD ACQ FOR 20-150 Comments: STEP-TIME=6.25S, expected acq count rate is 100 per second Exposure_Number: 20 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 979.2S Special_Requirements: Comments: Exposure_Number: 30 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 2 Time_Per_Exposure: 326.4S Special_Requirements: Comments: Exposure_Number: 40 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 979.2S Special_Requirements: Comments: Exposure_Number: 50 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 2 Time_Per_Exposure: 326.4S Special_Requirements: Comments: Exposure_Number: 60 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 979.2S Special_Requirements: Comments: Exposure_Number: 70 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 2 Time_Per_Exposure: 326.4S Special_Requirements: Comments: Exposure_Number: 80 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 979.2S Special_Requirements: Comments: Exposure_Number: 90 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 2 Time_Per_Exposure: 326.4S Special_Requirements: Comments: Exposure_Number: 100 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 979.2S Special_Requirements: Comments: Exposure_Number: 110 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 2 Time_Per_Exposure: 326.4S Special_Requirements: Comments: Exposure_Number: 120 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 979.2S Special_Requirements: Comments: Exposure_Number: 130 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 2 Time_Per_Exposure: 326.4S Special_Requirements: Comments: Exposure_Number: 140 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1662 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 1 Time_Per_Exposure: 979.2S Special_Requirements: Comments: Exposure_Number: 150 Target_Name: BZ-CAM Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1437 Optional_Parameters: FP-SPLIT=STD Number_of_Iterations: 2 Time_Per_Exposure: 326.4S Special_Requirements: Comments: Data_Distribution ! 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