6494( 7) - 11/21/96 09:25 - [ 0] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6494 Version: 7 Check-in Date: 21-Nov-1996 09:18:42 1.Proposal Title: Changing perspectives on accretion disk winds ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle BINARIES AND STAR FOR GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: KEITH MASON MULLARD SPACE SCIENCE LABORATORY CoI: Dr. J. E. Drew Imperial College of Science, Technology & N Medicine CoI: C. Knigge Space Telescope Science Institute N CoI: Dr. J. Stone University of Maryland N CoI: D. Proga Imperial College of Science, Technology & N Medicine ------------------------------------------------------------------------------------ 6. Abstract We seek to extend our highly successful study of wind-formed lines in disk-accreting CV by observing systems at higher orbital inclination than previously, thus probing the wind to greater heights above the disk. Our previous HST data, on the system UX UMa, point to a number of hitherto unexpected phenomena in the wind, including a thick layer at its base where very little acceleration apparently takes place. We have developed a model to explain these data, but there is a pressing need to test whether it is more generally applicable. The model predicts that there should be noticable differences in the appearance of the lines as the inclination is changed between about 70 and 80 degrees. The proposed target is RW Tri. We intend to perform time resolved UV spectroscopy through eclipse to probe the wind structure, and also to sample the light curve through the orbital cycle to test for asymmetries in the disk or the wind which would affect the interpretation of the eclipse light curves. Our goal is to build a full and self-consistent model for the wind in CV and to determine where and how the wind originates. We will then be in a position to investigate what drives the wind and the effect it has on the underlying accretion disk structure. ------------------------------------------------------------------------------------ Observations Description ------------------------ Our scientific objectives call for time sequences of spectra which (i) follow the target through eclipse by the companion star and (ii) sample the rest of the orbital cycle to characterise orbital-phase-linked variations in the line profiles. Following our cycle 5 observations of UX UMa, we plan to observe RW Tri using the G140L grating on side~1 of the GHRS which gives the optimum balance between spectral resolution and wavelength coverage for this application. The sequences of observations are chosen to optimise coverage of the target orbital cycle with the sampling implied by the HST orbit. We propose to perform each sequence in two grating settings centered at 1293A and 1523A so as to cover a range of lines of different excitation (e.g. HeII 1640A, CIV 1550A, SiIV 1397A, and NV 1240A). The orbital period of RW~Tri is 5.57 hours. Each HST orbit will cover just over 0.1 orbital cycles in RW Tri, and the eclipse itself covers 0.12 cycles, or 40 minutes. The whole eclipse cannot be accomodated comfortably in one unocculted HST orbit and still allow the pre- and post-eclipse spectrum to be properly sampled. It is important to stress the need for good coverage immediately before and after eclipse to provide a solid reference with which to compare the changes in the spectrum during eclipse. Thus the observations are designed to cover eclipse ingress and eclipse egress on separate visits. The elipse-ingress and eclipse-egress visits are planned to consist of 4 and 2 contiguous HST orbits respectively, repeated in the two grating settings (4 visits in total). The four HST-orbit sequence will start just before phase 0.4 in the RW Tri orbit and sample phase regions near 0.4, 0.7, 0.0 (eclipse) and 0.25. This sequence will be timed to emphasise the eclipse ingress and the pre-eclipse region in the third of the four HST orbits. The two HST-orbit sequence will begin at about phase 0.8 and will monitor the eclipse during the second of the two HST orbits, emphasising eclipse egress and the post-eclipse region. The first orbit of a sequence is assumed to contain the target acquisition, so that the amount of science data in this orbit is curtailed. The phase in the RW~Tri binary cycle at which this first science data segment should start is specified using the PHASE command. Provided this observation starts on time as predicted by RPS2, subsequent orbits should occur at the intended RW~Tri binary phases, in particular the eclipse coverage should be satisfactory. However, if the time required to acquire the target differs from that predicted by RPS2, then the PHASE of the first science data will also need to be modified to reflect this. The binary phase of subsequent orbits will not change, however, so as a check we include as a comment the required starting phase of the second orbit of science data in each visit. The total number of HST orbits required for this programme is 12. As described above, this is determined by the orbital phase coverage needed and not by signal-to- noise requirements. RW~Tri is bright enough to yield phase and spectrally resolved spectra suitable for our needs. The continuum near 1500A should yield a flux of 6 x 10-14 erg cm-2 s-1 A-1 (based on the IUE ULDA), which will yield a S/N of 10 per diode in about 3 minutes (0.008 in phase). The peak flux of the CIV emission line (the brightest of the wind-formed resonance lines) is at least twice that of the continuum. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6494( 7) - 11/21/96 09:25 - [ 1] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 RWTRI STAR,Nova- RA=02H 25M 36.14S +/- 0.2", J2000 V = 13.2+/-0.1 like,Interacting Binary DEC=+28D 05' 51.3" +/- 0.2", B-V = 0.0 PLATE-ID=01H7 F-LINE(1549)=2.0+/-0.5e-13 W-LINE(1549)=20+/-5 F-CONT(1500)=6.0+/-1e-14 F-LINE(1240)=1.4+/-0.5e-13 W-LINE(1240)=8.0+/-3 F-CONT(1200)=6.0+/-1e-14 A(V) = 0.6+/-0.2 Comments: Eclipsing star - mid-eclipse V=15.6 6494( 7) - 11/21/96 09:25 - [ 2] Visit: 01 Visit Requirements: GROUP 1-4 WITHIN 7D GROUP 1-2 WITHIN 1D PERIOD 0.231883297D AND ZERO-PHASE JD2441129.36487 On Hold Comments: Additional Comments: Exact timings adjustable in consultation with PI to accommodate actual HST orbit schedule most efficiently Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 RWTRI HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,LOCATE=DEF 1 90.0 S ONBOARD ACQuisition FOR 2-5 ------------------------------------------------------------------------------------------------------------------------------------ 2 RWTRI HRS RAPID 2.0 G140L 1293 SAMPLE-TIME=5 1 11 M NO SPLIT PHASE 0.37 TO 0.41 Comments: Starting exposure in the PHASE range indicated will ensure coverage of eclipse ingress in exposure 4 assuming nominal acquisition time ------------------------------------------------------------------------------------------------------------------------------------ 3 RWTRI HRS RAPID 2.0 G140L 1293 SAMPLE-TIME=5 1 43 M Comments: This exposure should start between phase 0.57 and 0.61 ------------------------------------------------------------------------------------------------------------------------------------ 4 RWTRI HRS RAPID 2.0 G140L 1293 SAMPLE-TIME=5 1 43 M Comments: Eclipse ingress ------------------------------------------------------------------------------------------------------------------------------------ 5 RWTRI HRS RAPID 2.0 G140L 1293 SAMPLE-TIME=5 1 43 M ------------------------------------------------------------------------------------------------------------------------------------ 6494( 7) - 11/21/96 09:25 - [ 3] Visit: 02 Visit Requirements: PERIOD 0.231883297D AND ZERO-PHASE JD2441129.36487 On Hold Comments: Additional Comments: Exact timings adjustable in consultation with PI to accommodate actual HST orbit schedule most efficiently Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 6 RWTRI HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,LOCATE=DEF 1 90.0 S ONBOARD ACQuisition FOR 7-8 ------------------------------------------------------------------------------------------------------------------------------------ 7 RWTRI HRS RAPID 2.0 G140L 1293 SAMPLE-TIME=5 1 11 M NO SPLIT PHASE 0.76 TO 0.80 Comments: Starting exposure in the PHASE range indicated will ensure coverage of eclipse egress in exposure 8 assuming nominal acquisition time ------------------------------------------------------------------------------------------------------------------------------------ 8 RWTRI HRS RAPID 2.0 G140L 1293 SAMPLE-TIME=5 1 43 M Comments: Eclipse egress. This exposure should start between phase 0.96 and 0.00 ------------------------------------------------------------------------------------------------------------------------------------ 6494( 7) - 11/21/96 09:25 - [ 4] Visit: 03 Visit Requirements: GROUP 3-4 WITHIN 1D PERIOD 0.231883297D AND ZERO-PHASE JD2441129.36487 On Hold Comments: Additional Comments: Exact timings adjustable in consultation with PI to accommodate actual HST orbit schedule most efficiently Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 9 RWTRI HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,LOCATE=DEF 1 90.0 S ONBOARD ACQuisition FOR 10-13 ------------------------------------------------------------------------------------------------------------------------------------ 10 RWTRI HRS RAPID 2.0 G140L 1523 SAMPLE-TIME=5 1 11 M NO SPLIT PHASE 0.37 TO 0.41 Comments: Starting exposure in the PHASE range indicated will ensure coverage of eclipse ingress in exposure 12 assuming nominal acquisition time ------------------------------------------------------------------------------------------------------------------------------------ 11 RWTRI HRS RAPID 2.0 G140L 1523 SAMPLE-TIME=5 1 43 M Comments: This exposure should start between phase 0.57 and 0.61 ------------------------------------------------------------------------------------------------------------------------------------ 12 RWTRI HRS RAPID 2.0 G140L 1523 SAMPLE-TIME=5 1 43 M Comments: Eclipse ingress ------------------------------------------------------------------------------------------------------------------------------------ 13 RWTRI HRS RAPID 2.0 G140L 1523 SAMPLE-TIME=5 1 43 M ------------------------------------------------------------------------------------------------------------------------------------ 6494( 7) - 11/21/96 09:25 - [ 5] Visit: 04 Visit Requirements: PERIOD 0.231883297D AND ZERO-PHASE JD2441129.36487 On Hold Comments: Additional Comments: Exact timings adjustable in consultation with PI to accommodate actual HST orbit schedule most efficiently Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 14 RWTRI HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,LOCATE=DEF 1 90.0 S ONBOARD ACQuisition FOR 15-16 ------------------------------------------------------------------------------------------------------------------------------------ 15 RWTRI HRS RAPID 2.0 G140L 1523 SAMPLE-TIME=5 1 11 M NO SPLIT PHASE 0.76 TO 0.80 Comments: Starting exposure in the PHASE range indicated will ensure coverage of eclipse egress in exposure 16 assuming nominal acquisition time ------------------------------------------------------------------------------------------------------------------------------------ 16 RWTRI HRS RAPID 2.0 G140L 1523 SAMPLE-TIME=5 1 43 M Comments: Eclipse egress. This exposure should start between phase 0.96 and 0.00 ------------------------------------------------------------------------------------------------------------------------------------ 6494( 7) - 11/21/96 09:25 - [ 6] Summary Form for Proposal 6494 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ RAPID ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN LOCATE=DEF SAMPLE-TIME=5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category BINARIES AND STAR FORMATION ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GROUP 1-4 WITHIN 7D GROUP 1-2 WITHIN 1D PERIOD 0.231883297D AND ZERO-PHASE JD2441129.36487 ONBOARD ACQuisition FOR 2-5 NO SPLIT PHASE 0.37 TO 0.41 ONBOARD ACQuisition FOR 7-8 NO SPLIT PHASE 0.76 TO 0.80 GROUP 3-4 WITHIN 1D PERIOD 0.231883297D AND ZERO-PHASE JD2441129.36487 ONBOARD ACQuisition FOR 10-13 ONBOARD ACQuisition FOR 15-16 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N1 G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names RWTRI ------------------------------------------------------------------------------------------------------------------------------------