8227( 5) - 04/12/99 06:32 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8227 Version: 5 Check-in Date: 12-Apr-1999 06:31:45 1.Proposal Title: The Shock Cones and Underlying Stars in Interacting Wolf-Rayet Binaries ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Michael Shara Space Telescope Science Institute CoI: Ms. Debra Wallace Space Telescope Science Institute Y CoI: Dr. Rex Saffer Villanova University N CoI: Dr. Anthony Moffat Universite de Montreal N CoI: Dr. Virpi Niemelae La Plata Observatory N CoI: Mr. David Zurek Space Telescope Science Institute N ------------------------------------------------------------------------------------ 5. Abstract We are proposing STIS longslit spectroscopy of 3 HST-resolved Wolf-Rayet binary stars. Our HST/WFPC2 Cycle 6 and 7 SNAP proposals clearly resolve these 3 Wolf-Rayet (WR) stars with previously suspected or debated companions. From ground-based radio data, two of these WR stars are also known to be strong emitters of non-thermal radiation. Our 1998 Astronomical Journal paper conclusively linked these two traits, demonstrating the coincidence of location of the non-thermal emission with the wind interaction region (bow shock head) between each pair. STIS spectra will provide clear determinations of the natures of each of the components of these 3 close WR binaries, and possibly, their wind collision regions. ------------------------------------------------------------------------------------ 8227( 5) - 04/12/99 06:32 - [ 2] Observations Description ------------------------ Binary Wolf-Rayet stars, which are themselves the descendents of massive O stars, are also likely to have O star companions. Our first goal, to spectrographically classify the companions, will be accomplished using the ratio of the strengths of the He II lambda4542 and He I lambda4471 absorption features. A resolution element with 2Angstrom\ FWHM and a signal to noise ratio (S/N) of 50--60 per resolution element are required. Thus, we require observations in medium resolution gratings G430M and G750M to achieve the desired spectrographic coverage and resolution. We provide further details below in our exposure time calculations. Our second goal, to probe the interaction between the winds of the WR stars and their companions, is best achieved by searching for velocity structure in H Alpha\ . The H Alpha\ observations will sample the hydrogen-rich material in the O star winds. We propose to obtain additional spectra at these settings in the G750M gratings at a resolution betw een 25--50 kms, in winds with term inal velocities of thousands of kms. The G430M and G750M gratings provide resolution elements (2DeltaLambda) of 0.55 and 1.1 Angstrom\ FWHM, respectively. Thus, if we aim to achieve original S/N ratios of 30 and 40, we can resample and degrade the resolutions by factors of 4 and 2 to achieve the desired resolution, at the same time increasing the S/N ratios by factors of 2 and sqrt2, respectively, to approximately 60 per resolution element for both configurations. Our targets are well-isolated from neighbors. Since we have well-known positions from our HST SNAP (which will not change as the binaries have periods of many centuries or longer), we will specify a roll angle so as to place both components on the 52*0.5 long slit. This slit provides higher throughput than the narrower slits and, when combined with our precise positions, makes it unnecessary to perform a peakup after target acquisition. We have used the Cycle 8 STIS exposure time calculator in the STIS Web page to calculate the exposure times. An O 5 model input spectrum and average background levels for the bright earth and zodiacal light were selected. The input data and resulting exposure time estimates in seconds are given below. The S/N ratios are specified for the resampled resolution elements. Accounting for overheads such as guide star acquisitions, target acquisitions, grating changes, and CCD read times, to obtain the medium resolution spectra requires 1 orbit for WR 86, three orbits for WR 146, and two orbits for WR 147, for a total of 6 spacecraft orbits. Real Time Justification ----------------------- None. Calibration Justification ------------------------- Additional Comments ------------------- WR86 17:18:23.05 -34:24:30.5 -28.0 10.18 10.20 0.53 WR146 20:35:47.1 41:22:44.7 64.0 13.62 13.88 2.77 WR147 20:36:43.39 40:21:07.6 45.0 13.86 16.02 4.32 ------------------------------------------------------------------------------------ 8227( 5) - 04/12/99 06:32 - [ 3] Data Distribution Paper Products: YES Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8227( 5) - 04/12/99 06:32 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 WR86 STAR, Wolf Rayet - WC, RA=17H 18M 23.05S +/- 0.3S, DEC= J2000 E(B-V) = 0.83+/-0.3 Interacting Binary -34D 24' 30.5" +/- 0.3", PLATE- V = 10.18 ID=06Q3 B-V = 0.50 Comments: Other guy: V=10.2, B-V=.53 2 WR146 STAR, Wolf Rayet - WC, RA=20H 35M 47.10S +/- 0.3S, J2000 V = 13.88 Interacting Binary DEC=41D 22' 44.69" +/- 0.3", B-V = 2.44 PLATE-ID=00VV E(B-V) = 2.77 Comments: Brighter guy: V=13.64; B-V=2.7 3 WR147 STAR, Wolf Rayet - WN, RA=20H 36M 43.39S +/- 0.3S, J2000 E(B-V) = 4.32+/-0.3 Interacting Binary DEC=40D 21' 7.57" +/- 0.3" V = 16.02 B-V = 4.09 Comments: Brighter guy: V=13.86, B-V=4.06 8227( 5) - 04/12/99 06:32 - [ 5] Visit: 01 Visit Priority: Visit Requirements: ORIENT 331.5D TO 332.5D ORIENT 151.5D TO 152.5D 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 WR86 STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 .7 S ONBOARD ACQ FOR 20 CD CCDGAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ 20 WR86 STIS/C ACCUM 52X0.5 G430M 4451 CR-SPLIT=2 1 22 S EXPAND MAX DUR 125% CD Comments: S/N = 55 as RPS2'd S/N=62 ------------------------------------------------------------------------------------------------------------------------------------ 30 WR86 STIS/C ACCUM 52X0.5 G750M 5734 CR-SPLIT=2 1 9.2 S EXPAND MAX DUR 125% CD Comments: S/N = 55 as RPS2'd S/N=62 ------------------------------------------------------------------------------------------------------------------------------------ 40 WR86 STIS/C ACCUM 52X0.5 G750M 6581 CR-SPLIT=2 1 11 S EXPAND MAX DUR 125% CD Comments: S/N = 55 as RPS2'd S/N=63 ------------------------------------------------------------------------------------------------------------------------------------ 50 WR86 STIS/C ACCUM 52X0.5 G750M 6581 CR-SPLIT=2 1 150 S EXPAND POS TARG 0.5, 0 CD Comments: dave and I did this this assumes x perp to slit length as per part B prop instr. ------------------------------------------------------------------------------------------------------------------------------------ 8227( 5) - 04/12/99 06:32 - [ 6] Visit: 02 Visit Priority: Visit Requirements: ORIENT 63.5D TO 64.5D ORIENT 243.5D TO 244.5D 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 ------------------------------------------------------------------------------------------------------------------------------------ 100 WR146 STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 3.8 S ONBOARD ACQ FOR 110 CD ------------------------------------------------------------------------------------------------------------------------------------ 110 WR146 STIS/C ACCUM 52X0.5 G750M 6581 CR-SPLIT=2 1 86 S EXPAND MAX DUR 125% CD Comments: S/N=55 no rps2 change ------------------------------------------------------------------------------------------------------------------------------------ 120 WR146 STIS/C ACCUM 52X0.5 G750M 5734 CR-SPLIT=2 1 224 S EXPAND MAX DUR 125% CD Comments: S/N=55 no rps2 change ------------------------------------------------------------------------------------------------------------------------------------ 130 WR146 STIS/C ACCUM 52X0.5 G430M 4451 CR-SPLIT=2 1 1300 S EXPAND CD Comments: S/N=32 ------------------------------------------------------------------------------------------------------------------------------------ 8227( 5) - 04/12/99 06:32 - [ 7] Visit: 03 Visit Priority: Visit Requirements: ORIENT 44.5D TO 45.5D ORIENT 224.5D TO 225.5D 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 ------------------------------------------------------------------------------------------------------------------------------------ 200 WR147 STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 5 S ONBOARD ACQ FOR 210 CD Comments: S/N=55 ------------------------------------------------------------------------------------------------------------------------------------ 210 WR147 STIS/C ACCUM 52X0.5 G750M 6581 CR-SPLIT=2 1 310 S CD Comments: S/N=55 no rps2 change ------------------------------------------------------------------------------------------------------------------------------------ 220 WR147 STIS/C ACCUM 52X0.5 G750M 5734 CR-SPLIT=2 1 325 S CD Comments: S/N=20 rps2 S/N=20 ------------------------------------------------------------------------------------------------------------------------------------ 230 WR147 STIS/C ACCUM 52X0.5 G430M 4451 1 500 S EXPAND CD Comments: S/N=6.5 rps2 S/N=7.5 no target saturation ------------------------------------------------------------------------------------------------------------------------------------ 240 WR147 STIS/C ACCUM 52X0.5 G430M 4451 CR-SPLIT=3 1 6500 S EXPAND CD Comments: S/N=6.5 rps2 S/N=7.5 no target saturation ------------------------------------------------------------------------------------------------------------------------------------ 8227( 5) - 04/12/99 06:32 - [ 8] Summary Form for Proposal 8227 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F25ND3 52X0.5 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT CR-SPLIT=2 CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 331.5D TO 332.5D ORIENT 151.5D TO 152.5D ONBOARD ACQ FOR 20 CCDGAIN=4 EXPAND MAX DUR 125% EXPAND POS TARG 0.5, 0 ORIENT 63.5D TO 64.5D ORIENT 243.5D TO 244.5D ONBOARD ACQ FOR 110 EXPAND ORIENT 44.5D TO 45.5D ORIENT 224.5D TO 225.5D ONBOARD ACQ FOR 210 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G430M G750M ------------------------------------------------------------------------------------------------------------------------------------ Target Names WR86 WR146 WR147 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 4451 5734 6581 ------------------------------------------------------------------------------------------------------------------------------------