! $Id: 6544,v 8.1 1996/07/12 16:01:31 pepsa Exp $ ! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /pisces/data1/long/proposals/hst6/sscyg/6544.prop ! Generated by PREPROCESSOR, version 6.0e ! Date: Fri Feb 9 16:57:03 EST 1996 Proposal_Information Title: Dwarf Novae in Quiescence Proposal_Category: GO Scientific_Category: BINARIES AND STAR FORMATION Cycle: 6 Investigators PI_Name: Knox S. Long PI_Institution: Space Telescope Science Institute CoI_Name: Timothy R. Kallman CoI_Institution: Goddard Space Flight Center Contact: CoI_Name: Yuan-Kuen Ko CoI_Institution: University of Michigan Contact: CoI_Name: Christian Knigge CoI_Institution: Space Telescope Science Institute Contact: CoI_Name: Christopher Mauche CoI_Institution: Lawrence Livermore National Laboratory Contact: Abstract: We propose to use the GHRS to obtain moderate (Lambda / Delta Lambda ~ 2000 ) resolution, high S/N 1160-1660 A spectra of the dwarf novae SS Cyg and WX Hyi in quiescence. We will carry out a detailed study of the resonance lines -- N V, CII, Si IV, C IV, and He II -- in these spectra to determine the surface flux of the resonance lines as a function of radius in the disk. The derived surface fluxes will allow us to determine whether X-ray photoionization of the disk explains the UV lines and the underlying continuum of these two dwarf novae (and by extension other cataclysmic variables) whose UV spectrum appears not to be dominated by the white dwarf in quiescence. We will also use the GHRS spectra to conduct a sensitive search for the narrow metal absorption lines that should reveal the hidden WD in these two dwarf novae. Finally, we will use the spectra in an attempt to constrain suggestions that absence of material in the inner accretion disk of a quiescent dwarf nova causes the delay in UV rise to outburst that is observed in dwarf nova outbursts. Questions Observing_Description: We propose to obtain 3 observations of SS Cyg and of WX Hyi with the GHRS and the G140L grating in order to produce spectra with a resolution of 1750 at Lyman alpha to 2400 at C IV. Each observation will consist of two wavelength settings so that we may obtain a composite spectrum from 1160-1660 Angstrom and each observation will require two orbits to obtain a S/N of at least 70 per resolution element. This wavelength coverage is necessary so that we can study the 1s- 2p transition of N V, whose emission in the photoionization models is concentrated close to the WD, and the same transition in C IV, which should be much more extended. Another important transition Si IV will be sampled at both grating settings. In addition, the wavelength range 1160-1660 Angstrom contains a number of important absorption lines, including C III 1176, Si III 1295-1303, and Si IV 1394,1403 which would be expected if the WD temperatures are between 20,000 K and 60,000 K and N V1239,1243 and O V 1371 if the temperature is higher. The lower temperature lines were all seen in our FOS spectra of the WD in U Gem with 0.1 < EW < 2 A. We could have elected to use the FOS for these observations, but the resolution is lower, its efficiency at the shorter wavelengths is much lower, and the acquisitions, particularly for SS Cyg (because of its variability) would take longer with the FOS. We propose to space the observations out over a 9 week period for SS Cyg and over a 8 day period for WX Hyi. This will ensure that at least two of the observations are obtained when the system is in quiescence and avoid the necessity of requesting hard to schedule TOO observations. Given the duty cycle for outbursts (~20%) at least two of the three observations will be in quiescence and if the third observation occurs during outburst it will produce truly spectacular spectra of the wind-created lines (whose structure we would be pleased to analyze as well). For SS Cyg, in two orbits, each grating setting will be about 2400 s long, and will result in about 1200 counts per quarter stepped diode given the continuum flux from SS Cyg, which is about 1.2 * 10^-13 ergs/cm**2/s/A at 1300 Angstrom. Thus the S/N in the continuum in quiescence will be about 100 per two diode wide resolution element. We would observe in ACCUM mode with relatively short 2 minute increments in order to allow us to search for short-term variability in the disk, the WD, or the boundary layer. WX Hyi is a CVZ target and so the available exposure times in two orbits will be about 4200 s per grating in the first 2 orbit observation and potentially as large as 5600 s for the remaining observations. The continuum flux from WX Hyi toward the end of quiescence is 3.2*10^-14 ergs/cm**2/s/A at 1300 Angstrom. For the shorter exposures, we will obtain 575 counts per quarter-stepped diode, resulting in a S/N of 70 per resolution element. Real_Time_Justification: The observations of SS Cyg should be scheduled at intervals of 3 weeks. This will ensure that two of the three observations occur in quiescence. The observations of WX Hyi should be scheduled at intervals of separated by 4 days( although this may not be possible given the limited duration of CVZ opportunities). This will ensure that two of the observations occur in quiescence. There are NO orbital phase requirements. Since we have not asked that these observations be TOO observations, there is a possiblitity that the objects will be in outburst for one of the observations. Outbursts typically last a day for WX Hyi and 7-14 days for SS Cyg. Therefore it is important that the observations not be scheduled too close together since in that case an outburst could wipe out the primary science in several visits. We have adopted therefore included special requirements to prevent subsequent observations of the same target from coming too close together. Individual 2-orbit observations of WX Hyi are long enough that they will cover an entire orbital period. SS Cyg and WX Hyi are monitored by the AAVSO. We will work closely with Janet Mattei, with whom we have an established and excellent relationship, in order to assure that we have comprehensive optical coverage of these DN both before and during the observations. Calibration_Justification: Additional_Comments: Fixed_Targets Target_Number: 1 Target_Name: SS-CYG Alternate_Names: Description: STAR,DWARF NOVA,ACCRETION DISK, Position: RA=21H 42M 42.56S +/- 1", DEC=43D 35' 9.8" +/- 1", PLATE-ID=01KD Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: F(1300)=1.6+/-0.4e-13 Comments: Flux listed above is in quiescence. In outburst, the flux peaks near 1e-11 at 1300 A. Position is revised position from Downes and Shara catalogue Target_Number: 2 Target_Name: WX-HYI Alternate_Names: Description: STAR,DWARF NOVA,ACCRETION DISK,INTERACTING BINARY, Position: RA=2H 09M 50.66S +/- 1", DEC=-63D 18' 39.9" +/- 1", PLATE-ID=04CA Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: F(1300)=2.0+/-0.4e-14 Comments: Flux is for low state as measured with HUT on Astro-2. High state flux is about 1.4e-12 Position is revised position from Downes and Shara catalogue Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: SS-CYG Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 18S Special_Requirements: ONBOARD ACQ FOR 20-30 Comments: STEP-TIME=2 (200 counts/sec) Exposure_Number: 20 Target_Name: SS-CYG Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1436 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 30 Target_Name: SS-CYG Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1661 Optional_Parameters: FP-SPLIT=NO,STEP-PATT=DEF Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Visit_Number: 02 Visit_Requirements: AFTER 01 BY 16D On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: SS-CYG Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 18S Special_Requirements: ONBOARD ACQ FOR 20-30 Comments: STEP-TIME=2 (200 counts/sec) Exposure_Number: 20 Target_Name: SS-CYG Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1436 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 30 Target_Name: SS-CYG Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1661 Optional_Parameters: FP-SPLIT=NO,STEP-PATT=DEF Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Visit_Number: 03 Visit_Requirements: AFTER 02 BY 16D On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: SS-CYG Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 18S Special_Requirements: ONBOARD ACQ FOR 20-30 Comments: STEP-TIME=2 (200 counts/sec) Exposure_Number: 20 Target_Name: SS-CYG Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1436 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 30 Target_Name: SS-CYG Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1661 Optional_Parameters: FP-SPLIT=NO,STEP-PATT=DEF Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Visit_Number: 04 Visit_Requirements: CVZ On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: WX-HYI Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 54S Special_Requirements: ONBOARD ACQ FOR 20-50 Comments: STEP-TIME=6 (35 counts/sec) Exposure_Number: 20 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1436 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 30 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1661 Optional_Parameters: FP-SPLIT=NO,STEP-PATT=DEF Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 40 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1436 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 50 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1661 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Visit_Number: 05 Visit_Requirements: CVZ AFTER 04 BY 3D On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: WX-HYI Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 54S Special_Requirements: SEQ 10-50 NON-INT ONBOARD ACQ FOR 20-50 Comments: STEP-TIME=6 (35 counts/sec) Exposure_Number: 20 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1436 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 30 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1661 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 40 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1436 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 50 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1661 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Visit_Number: 06 Visit_Requirements: CVZ AFTER 05 BY 3D On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: WX-HYI Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 54S Special_Requirements: SEQ 10-50 NON-INT ONBOARD ACQ FOR 20-50 Comments: STEP-TIME=6 (35 counts/sec) Exposure_Number: 20 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1436 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 30 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1661 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 40 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1436 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Exposure_Number: 50 Target_Name: WX-HYI Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1375-1661 Optional_Parameters: STEP-PATT=DEF,FP-SPLIT=NO Number_of_Iterations: 20 Time_Per_Exposure: 108.8S Special_Requirements: Comments: Data_Distribution ! Defaults indicated; change if desired Medium: 8MM Blocking_Factor: 10 Ship_To: STSCI Ship_Via: Recipient_Email: long@stsci.edu ! Let us know what you think of this template and software! ! Please send a list of your likes and dislikes to your Program Coordinator