6761( 4) - 03/27/96 14:33 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6761 Version: 4 Check-in Date: 27-Mar-1996 14:30:29 1.Proposal Title: The Origin of Shock Emission in Proto- Planetary Nebulae ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle INTERSTELLAR MEDIUM GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Susan Trammell University of Chicago CoI: Robert Goodrich Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract While evolved planetary nebulae (PNe) have been well studied, the transition from the AGB to the PN phase of evolution is still poorly understood. In particular, the characteristics of the mass loss occurring during this transition period are not well known. We propose to probe this phase of evolution by obtaining Planetary Camera images of three bipolar proto- planetary nebulae (PPNe). Shock emission dominates the optical line spectra of the lobes of these objects and shocks probably play a significant role in their dynamic evolution. This shock emission is an excellent tracer of the ongoing mass outflow in these objects and affords a powerful probe into the geometry of the mass loss between the AGB and PN phases of evolution. Is the shock emission the result of a uniform flow impacting over the entire face of the nebula or is this emission formed in fast moving bullets of material? One model for the mass loss during this phase of evolution suggests that this outflow might be collimated. Do we see evidence for a collimated outflow in these objects? We will address these questions by obtaining narrow-band images of three PPNe through filters centered on emission lines known to be produced via shock heating. These PPNe are too small to be resolved in detail from the ground, but can be resolved using the high spatial resolution capabilities of HST. ------------------------------------------------------------------------------------ 6761( 4) - 03/27/96 14:33 - [ 2] Observations Description ------------------------ We will obtain images of PK 166-06D1 and M1-92 through narrow-band filters centered on [O I] lambda 6300A (F631N), and [S II] lambda 6717A + lambda 6731A (F673N). These lines are produced by the shock in the bipolar lobes and images in the light of these emission lines will reveal the distribution of shock heated gas in these objects. In addition, we will image PK 166-06D1 and M1-92 through an H-alpha filter (F656N) and a filter centered at lambda 5470A (F547M) which isolates a region of the continuum that is free of strong emission lines. The H-alpha emission will trace both the shock heated and reflected emission. The continuum images will be used to remove the continuum contribution to the emission line images and to trace the distribution of reflected light in these objects. All of the line emission seen in PK 118+08D1 is produced in the bipolar lobes by the shock heating. Since PK 118+08D1 is much fainter than PK 166-06D1 and M1-92 and the continuum emission is negligible, we will obtain images through only the H-alpha and [S II] filters (which will trace the morphology of the shock heated material) for this object. We have used the surface brightnesses of the relevant emission lines and continuum from our ground-based spectropolarimetry, combined with the total system throughput in each bandpass, to calculate the number of electrons per pixel expected to be collected by the Planetary Camera CCD. The throughputs for each filter were taken from the figures in section 8.2 of the WFPC2 Handbook. The effective resolution element of the Planetary Camera, based on models of the point-spread function, is approximately 3 x 3 pixels. We have calculated the S/N per resolution element (the S/N per pixel times 3) in order to estimate the exposure times. To study the detailed morphology of these objects, we require a S/N per resolution element of approximately 30-50. The bipolar lobes of the PPNe do not have equal brightnesses. Our exposure time estimates were calculated in order to yield the desired S/N in the fainter of the two bipolar lobes in PK 166-06D1 and M1-92. We have used the surface brightnesses in the bright lobe to estimate the exposure times for PK 118+08D1, since this object is much fainter than PK 166-06D1 and M1-92. The noise estimates include shot noise for the nebulae, readout noise, sky noise, dark current, and quantization noise, per the Handbook. The total integration time required for M1-92 is 67.5 minutes. The visibility period for this object is 53 minutes. Including overhead time, it will take 2 orbits to complete the desired observations. PK 166-06D1 is fainter than M1-92. Based on a similar exposure time calculation, we require three orbits to complete the all of the observations of this object. PK 118+08D1 is the faintest of the three objects, but lies in a CVZ. We require two CVZ orbits to complete the H-alpha and [S II] images of PK 118+08D1. Real Time Justification ----------------------- PK 118+08degrees1 lies in a 38-hour CVZ which occurs twice per year, and we request that it be observed during one of these CVZ periods. This will attain all of the scientific goals with a minimum of overhead. We have already obtained optical spectropolarimetry of all three targets. In addition, we have obtained ground-based narrow band imaging and imaging polarimetry of PK 166- 06degrees1 and M1-92. We recently obtained near-IR spectroscopy and near-IR imaging polarimetry of PK 166- 06degrees1 and M1-92 to investigate the near-IR properties of the shock emission in these objects. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6761( 4) - 03/27/96 14:33 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6761( 4) - 03/27/96 14:33 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PK166-06D1 ISM,PLANETARY NEBULA RA=4H 42M 53.85S +/- J2000 SURF-LINE(6300)=6.62+/-0.5e-14 0.04S,DEC=36D 6' 53.35" +/- SURF-LINE(6725)=1.81+/-0.3e-13 0.5",PLATE-ID=0049 SURF-LINE(6563)=1.35+/-0.3e-13 SURF-CONT(5500)=2.78+/-0.5e-16 Comments: These surface brightnesses are for the brighter lobe of this bipolar nebula. 2 M1-92 ISM,PLANETARY NEBULA RA=19H 36M 18.91S +/- J2000 SURF-LINE(6300)=2.40+/-0.3e-14 0.03S,DEC=29D 32' 50.18" +/- SURF-LINE(6725)=1.09+/-0.3e-13 0.5",PLATE-ID=000J SURF-LINE(6563)=1.29+/-0.1e-12 SURF-CONT(5500)=5.80+/-0.5e-15 Comments: These surface brightnesses are for the brighter lobe of this bipolar nebula. 3 PK118+08D1 ISM,PLANETARY NEBULA, RA=23H 56M 36.91S +/- J2000 SURF-LINE(6300)=2.11+/-0.8e-15 0.05S,DEC=70D 48' 18.31" +/- SURF-LINE(6725)=5.31+/-0.3e-15 0.8",PLATE-ID=02RF SURF-LINE(6563)=3.99+/-0.8e-15 SURF-CONT(5500)=6.95+/-0.8e-18 Comments: These surface brightnesses are for the brighter lobe of this bipolar nebula. 6761( 4) - 03/27/96 14:33 - [ 5] Visit: 01 Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 PK166-06D1 WFPC2 IMAGE PC1-FIX F631N 1 2500S END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 2 PK166-06D1 WFPC2 IMAGE PC1-FIX F547M 1 2700S END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 3 PK166-06D1 WFPC2 IMAGE PC1-FIX F656N 1 1000S ------------------------------------------------------------------------------------------------------------------------------------ 4 PK166-06D1 WFPC2 IMAGE PC1-FIX F673N 1 1200S ------------------------------------------------------------------------------------------------------------------------------------ 6761( 4) - 03/27/96 14:33 - [ 6] Visit: 02 Visit Requirements: 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 M1-92 WFPC2 IMAGE PC1-FIX F656N 1 350S ------------------------------------------------------------------------------------------------------------------------------------ 11 M1-92 WFPC2 IMAGE PC1-FIX F547M 1 300S ------------------------------------------------------------------------------------------------------------------------------------ 12 M1-92 WFPC2 IMAGE PC1-FIX F631N 1 3000S ------------------------------------------------------------------------------------------------------------------------------------ 13 M1-92 WFPC2 IMAGE PC1-FIX F673N 1 800S ------------------------------------------------------------------------------------------------------------------------------------ 6761( 4) - 03/27/96 14:33 - [ 7] Visit: 03 Visit Requirements: CVZ 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 ------------------------------------------------------------------------------------------------------------------------------------ 20 PK118+08D1 WFPC2 IMAGE PC1-FIX F656N 1 5000S ------------------------------------------------------------------------------------------------------------------------------------ 21 PK118+08D1 WFPC2 IMAGE PC1-FIX F673N 1 5200S ------------------------------------------------------------------------------------------------------------------------------------ 6761( 4) - 03/27/96 14:33 - [ 8] Summary Form for Proposal 6761 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements END ORBIT CVZ ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F631N F547M F656N F673N ------------------------------------------------------------------------------------------------------------------------------------ Target Names PK166-06D1 M1-92 PK118+08D1 ------------------------------------------------------------------------------------------------------------------------------------