Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4297c Report Date: 09-May-96:19:31 Version: ********** Check-in Date: ********** 1.Proposal Title: STABILITY OF THE WINDS FROM CATACLYSMIC VARIABLES: CYCLE3 MEDIUM ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID HOT STARS GO Sub Category ERUPTIVE BINARIES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Melvin G Hoare UNIVERSITY OF OXFORD UK 0865 273292 ------------------------------------------------------------------------------------ 7. Abstract We propose to use the FOS to obtain time-resolved, high-resolution UV spectra of the bright novalike variable V3885 Sgr in order to determine the stability of the winds from cataclysmic variables (CVs). Changes in the P Cygni line profiles on the flow timescale of the wind itself will provide vital clues for the ultimate goal of discovering the driving mechanism for these accretion disk winds. In particular we will look for transient features already seen in radiatively driven winds from hot single stars. With the high S/N accumalated spectra we will also be able to determine the extent to which many of the subordinate lines in the spectrum have wind-formed components. This will substantially increase our understanding of the ionization state of the wind which has implications for the total mass loss rate and illuminating radiation field. The latter is sensitive to the character of the boundary layer which will tell us whether the white dwarf has been spun up to near breakup speed. Finally, the accumulated spectra can be used to constrain new NLTE accretion disk model atmospheres. The proposed observations will greatly further our understanding of the driving force behind the winds in CVs with subsequent implications for winds from other accretion disk systems such as protostars and AGN. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 0.33 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4297c PI: Melvin G Hoare Proposal Title: STABILITY OF THE WINDS FROM CATACLYSMIC VARIABLES: CYCLE3 MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Melvin G Hoare UNIVERSITY OF OXFORD UNITED KING X Janet E Drew UNIVERSITY OF OXFORD UNITED KING X Thomas R Marsh UNIVERSITY OF OXFORD UNITED KING X ------------------------------------------------------------------------------------ 3. Description of proposed observations. We propose to obtain two uninterrupted 10 minute exposures of V3885 Sgr: obtained as close as possible in time:one with the G130H grating and one with the G190H, both using the blue digicon. The latter grating is needed to determine the extent of the wind components in the important He II 1640 A and N IV 1718 A lines. We want the highest spectral resolution possible so we will use the 0.25x2.0 aperture. We will use the RAPID READOUT mode with 10 second exposures and 1 MHz data rate in order to look for variations in the line profiles on the flow timescale of the wind. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The only alternative UV satellite is the IUE and it does not have sufficient sensitivity to carry out our proposed observations. Any transient narrow components in the P Cygni line profiles are likely to be less than 10% of the wind terminal velocity in width i.e. <500 km/s. This would need the high resolution mode on IUE which requires exposures lasting many hours in order to obtain a moderate S/N spectrum of our target. We require time resolution of 10 seconds to achieve the major aim of determining the stability of the wind. The high S/N spectrum required to determine the extent of the wind-formed components in the subordinate lines can never be achieved with the IUE due to its limitation on S/N of little more than 10 sigma in each exposure. V3885 Sgr (CD -42 14462) is the second brightest (visual mag.=9.6-10.3) non-eclipsing, non-magnetic, novalike variable. Low inclination systems are required to provide a strong source of background continuum against which to see the absorption lines formed in the wind. The optically brightest novalike, IX Vel, appears to be at a moderately high inclination since the blueshifted absorption is not nearly so well developed. In the UV, V3885 Sgr is of comparable brightness to IX Vel. The average 1550 A continuum flux for V3885 Sgr is 3E-12 ergs/cm**2/s/A (see Fig. 5). With the G130H grating and 0.25 x 2.0 aperture this gives a count rate of 17 counts/s/diode. Hence in 10 seconds of exposure a S/N of 13 sigma is achieved which is sufficient to look for transient features in the line profile and to assess overall equivalent width changes. The full 10 minute integration accumulated will result in a S/N of about 100 sigma over most of the wavelength range as required for the detailed studies of the line profiles of the resonance and the weaker subordinate wind lines. Even at C III 1176 A the S/N will be about 35 sigma despite the dropping efficiency of the grating. V3885 Sgr is also reasonably close to the continuous viewing zone being only 19.5 degrees from the pole of HST's orbit which should help in scheduling 2 close uninterrupted 10 minute integrations. Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. We require 10 minute uninterrupted exposures in order to track any features observed in the line profiles over several flow timescales (approx. 1 minute). The discrete absorption components in OB star winds are observed to accelerate blueward over a few flow timescales. Note that the flow timescales in OB star winds are about 100 times slower than for CV winds. We also require the G130H and G190H exposures within the same acquisition so that we can construct a complete spectrum of the system at that particular state. There is probably some variablity of the wind profile on the 5.2 hour orbital period of V3885 Sgr as well as overall brightness changes on timescales of days. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Data reduction will be carried out using standard software made available through the UK STARLINK network. Periodicities in any variability in the line profiles will be searched for using standard techniques. The high S/N profiles of the wind-formed resonance and subordinate lines will be analysed using the Monte Carlo and Sobolev codes that we have developed (e.g. Drew 1987, Woods, Ph. D. Thesis 1991, Hoare & Drew 1992). The former will have the capability to deal with complex velocity fields such as those in which rotational motion and non-radial outflow are combined. We will compare the derived concentrations of the various ionic species with those predicted by our photo-ionization models to further constrain the boundary layer temperature and luminosity as well as the total wind mass loss rate. To analyse the disk lines we will collaborate with whoever has the most well developed NLTE disk atmosphere code at the time. ------------------------------------------------------------------------------------ 9. Description of previous HST work. Cycle 1 GO-2380 "Instabilities in Accretion Disks and the Outbursts of Dwarf Novae" Horne & Marsh Cycle 2 GO-3578 "Line Eclipse Mapping of an Accretion Disk Wind" Mason, Drew, Marsh, Horne, Cordova, Mauche, Raymond None of these are closely related. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). The STARLINK node at the University of Oxford will provide the data reduction and analysis packages required. ------------------------------------------------------------------------------------ 11. Address Information Name: MELVIN G HOARE Category: PI Institution: University of Oxford Address: DEPARTMENT OF PHYSICS ASTROPHYSICS KEBLE ROAD City: OXFORD State: Zip Code: OX1 3RH Country: UNITED KINGDOM Telephone: 0865 273292 Telex (or e-mail): 83295 NUCLOX G ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4297c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 CD-42D14462 A,151,905,906 PLATE-ID=04FS, 2000 1 V=10.0+/-0.4,B-V=0.00+/-0.02 V3885-SGR RA = 19H 47M 40.51S +/- 2 U-B=-0.75+/-0.08,E(B-V)=0.05 GSC7941- 0.03S, 3 F-CONT(1550)=3.0+/-1.5 E-12 00694 DEC = -42D 0' 25.9" +/- 0.3" 4 F-LINE(1550)=1.2+/-0.5 E-11 5 W-LINE(1550)=15+/-4 6 F-CONT(1718)=2.0+/-1.0 E-12 7 F-LINE(1718)=2.6+/-1.5 E-13 8 W-LINE(1718)=10+/-4 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4297c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 CD-42D14462 FOS/BL ACQ/ 4.3 G190H TYPE=UP 1 0.2S 1 1 CYCLE 3 / 1-6 PEAK ONBOARD ACQ FOR 2 SPATIAL SCAN ------------------------------------------------------------------------------------------------------------------------------------ 2 CD-42D14462 FOS/BL ACQ/ 1.0 G190H TYPE=UP 1 0.3S 1 1 CYCLE 3 / 1-6 PEAK ONBOARD ACQ FOR 3 SPATIAL SCAN ------------------------------------------------------------------------------------------------------------------------------------ 3 CD-42D14462 FOS/BL ACQ/ 0.5 G190H TYPE=UP 1 0.6S 1 1 CYCLE 3 / 1-6 PEAK ONBOARD ACQ FOR 4 SPATIAL SCAN ------------------------------------------------------------------------------------------------------------------------------------ 4 CD-42D14462 FOS/BL ACQ/ 0.25X2. G190H TYPE=UP 1 1.5S 1 1 CYCLE 3 / 1-6 PEAK 0 ONBOARD ACQ FOR 5- 6 SPATIAL SCAN ------------------------------------------------------------------------------------------------------------------------------------ 5 CD-42D14462 FOS/BL RAPID 0.25X2. G130H 1380 READ-TIME=10 1 10M 13 3 1 NON-INT / 5-6 0 STEP- 10S GROUP 5-6 NO GAP PATT=SINGLE SUB-STEP=4 COMB=YES ------------------------------------------------------------------------------------------------------------------------------------ 6 CD-42D14462 FOS/BL RAPID 0.25X2. G190H 1950 READ-TIME=10 1 10M 17 6 2 0 STEP- 10S PATT=SINGLE SUB-STEP=4 COMB=YES ------------------------------------------------------------------------------------------------------------------------------------ Scan Paramters Form Proposal ID: 4297c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 1 Exposure Logsheet lines: 1 FGS Scan: DWELL Dwell Only: dwell points/line: 3 Seconds per dwell: 1.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 2.8000 Angle between sides (degrees) 90.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 0.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): 1.4000 Width Offset (arc-sec): 0 ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 2 Exposure Logsheet lines: 2 FGS Scan: DWELL Dwell Only: dwell points/line: 6 Seconds per dwell: 1.00 Scan width (arc-secs): 0.7000 Scan length (arc-secs): 3.5000 Angle between sides (degrees) 90.00 Number of lines: 2 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 90.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): 1.7500 Width Offset (arc-sec): 0.3500 ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 3 Exposure Logsheet lines: 3 FGS Scan: DWELL Dwell Only: dwell points/line: 3 Seconds per dwell: 1.00 Scan width (arc-secs): 0.5000 Scan length (arc-secs): 0.5000 Angle between sides (degrees) 90.00 Number of lines: 3 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 90.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): 0.2500 Width Offset (arc-sec): 0.2500 ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 4 Exposure Logsheet lines: 4 FGS Scan: DWELL Dwell Only: dwell points/line: 7 Seconds per dwell: 1.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 0.4000 Angle between sides (degrees) 90.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 90.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): 0.2000 Width Offset (arc-sec): 0.0 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4297c [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK RAPID ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters TYPE=UP READ-TIME=10 STEP-PATT=SINGLE SUB-STEP=4 COMB=YES ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 0.33 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ERUPTIVE BINARIES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 3 / 1-6; ONBOARD ACQ FOR 2; SPATIAL SCAN ONBOARD ACQ FOR 3; ONBOARD ACQ FOR 4; ONBOARD ACQ FOR 5-6; NON-INT / 5-6; GROUP 5-6 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G190H G130H ------------------------------------------------------------------------------------------------------------------------------------ Target Names CD-42D14462 V3885-SGR GSC7941-00694 ------------------------------------------------------------------------------------------------------------------------------------