! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /spectre/data1/aroman/proposals/6761.prop ! Generated by PREPROCESSOR, version 6.1 ! Date: Wed Mar 27 14:29:23 EST 1996 Proposal_Information Title: The Origin of Shock Emission in Proto- Planetary Nebulae Proposal_Category: GO Scientific_Category: INTERSTELLAR MEDIUM Cycle: 6 Investigators PI_Name: Susan Trammell PI_Institution: University of Chicago CoI_Name: Robert Goodrich CoI_Institution: Space Telescope Science Institute Contact: 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. Questions Observing_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: Fixed_Targets Target_Number: 1 Target_Name: PK166-06D1 Alternate_Names: AFGL 618,IRAS04395+3601 Description: ISM,PLANETARY NEBULA Position: RA=4H 42M 53.85S +/- 0.04S,DEC=36D 6' 53.35" +/- 0.5",PLATE-ID=0049 Equinox: J2000 RV_or_Z: RA_PM: Dec_PM: Epoch: Annual_Parallax: Flux: SURF-LINE(6300)=6.62+/-0.5e-14 SURF-LINE(6725)=1.81+/-0.3e-13 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. Target_Number: 2 Target_Name: M1-92 Alternate_Names: IRAS19343+2926 Description: ISM,PLANETARY NEBULA Position: RA=19H 36M 18.91S +/- 0.03S,DEC=29D 32' 50.18" +/- 0.5",PLATE-ID=000J Equinox: J2000 RV_or_Z: RA_PM: Dec_PM: Epoch: Annual_Parallax: Flux: SURF-LINE(6300)=2.40+/-0.3e-14 SURF-LINE(6725)=1.09+/-0.3e-13 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. Target_Number: 3 Target_Name: PK118+08D1 Alternate_Names: M2-56,IRAS23541+7031 Description: ISM,PLANETARY NEBULA, Position: RA=23H 56M 36.91S +/- 0.05S,DEC=70D 48' 18.31" +/- 0.8",PLATE-ID=02RF Equinox: J2000 RV_or_Z: RA_PM: Dec_PM: Epoch: Annual_Parallax: Flux: SURF-LINE(6300)=2.11+/-0.8e-15 SURF-LINE(6725)=5.31+/-0.3e-15 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. Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: PK166-06D1 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F631N Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2500S Special_Requirements: END ORBIT Comments: Exposure_Number: 2 Target_Name: PK166-06D1 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F547M Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2700S Special_Requirements: END ORBIT Comments: Exposure_Number: 3 Target_Name: PK166-06D1 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 1000S Special_Requirements: Comments: Exposure_Number: 4 Target_Name: PK166-06D1 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F673N Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 1200S Special_Requirements: Comments: Visit_Number: 02 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: M1-92 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 350S Special_Requirements: Comments: Exposure_Number: 11 Target_Name: M1-92 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F547M Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 300S Special_Requirements: Comments: Exposure_Number: 12 Target_Name: M1-92 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F631N Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 3000S Special_Requirements: Comments: Exposure_Number: 13 Target_Name: M1-92 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F673N Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 800S Special_Requirements: Comments: Visit_Number: 03 Visit_Requirements: CVZ On_Hold_Comments: Visit_Comments: Exposure_Number: 20 Target_Name: PK118+08D1 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 5000S Special_Requirements: Comments: Exposure_Number: 21 Target_Name: PK118+08D1 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F673N Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 5200S Special_Requirements: Comments: Data_Distribution ! 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