9100( 11) - 05/23/03 11:26 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9100 Version: 11 Check-in Date: 23-May-2003 11:24:00 1.Proposal Title: High-Velocity Collimated Outflows and Equatorial Toroids in Cool Stars: A Study of V Hydrae and PI^1 Gru ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Raghvendra Sahai Jet Propulsion Laboratory, Caltech CoI: Prof. Mark Morris UCLA N CoI: Dr. John Krist STSCI N CoI: Dr. Ken Young CfA N CoI: Prof. Gillian Knapp Princeton University N CoI: Prof. Cecilia Barnbaum Valdosta State University N ------------------------------------------------------------------------------------ 5. Abstract The two cool red giant stars V Hya and PI^1 Gru show strong observational evidence for the presence of high-velocity collimated outflows and equatorial toroids, both of which have been postulated to play significant roles in the formation of bipolar planetary nebulae. However the limited resolution of existing ground-based observations makes it impossible to unambiguously identify structures which reveal the mechanism of jet formation or elucidate the cause of bipolarity. We propose HST imaging and long-slit spectroscopic observations of the circumstellar environment of V Hya and PI^1 Gru. These observations will provide the first high-resolution images at any wavelength of these key objects. We will thus obtain an unprecedentedly high- resolution glimpse of AGB stars transitioning into preplanetary nebulae, allowing us to probe the structure and kinematics of their very fast outflows and the relationship of those outflows to the structures seen in molecular line emission. Our HST study of these transition objects should elucidate the nature and history of the mass- loss processes which terminate the AGB evolution of intermediate-mass stars and begin their transition into the proto-planetary and planetary nebula phases. ------------------------------------------------------------------------------------ 9100( 11) - 05/23/03 11:26 - [ 2] Observations Description ------------------------ We will obtain both short and long exposures of both V Hya and PI^1 Gru (in order to optimally correct for saturation effects) with WFPC2 on the PC using the F555W & F814W broad- band filters and the F656N narrow-band filter. The continuum filters will provide scattered-light images of the circumstellar environment in 2 colors, necessary for a quantitative analysis of its 3-D structure and dust properties. We estimate that the scattering optical depths in the high-velocity outflow are ~0.1 at an offset Phi=1'' from the center, varying perhaps as phi^-3. Assuming, as derived in the case of the Egg Nebula CRL2688, a substantial radial extinction (~6) close to the star (Sahai et al 1998b) which could reduce the stellar flux by a factor 500, we expect the surface brightness to be ~ 1 mJy/arcsec^2 at Phi=1''. Detecting this with good S/N=(say)20 in F555W in the PC would take 40 sec. Due to the large uncertainty in the radial extinction, we will include pairs of short (~1 sec), intermediate (~10 sec) and and long (~100) sec exposures for each filter. The WFPC2 imaging will require 1 orbit for each object. This basic observation set will be repeated after a suitable interval, allowing the spacecraft to roll around the target by ~45degrees; thus the structures intrinsic to V Hya & PI^1 Gru (HVO, disk) will have rotated on the detector by the same angle. The scattered light pattern from the telescope optics, however, will remain unrotated, so that any feature which rotates in the image will be associated with our targets. Thus, we will need a total of 4 orbits for the WFPC2 observations of both sources. Because V Hya and PI^1 Gru are bright stars, the most challenging aspect of the WFPC2 data analysis will be to isolate the contribution of scattered light from the central star due to telescope optics from that intrinsic to the circumstellar environment in our targets. In order to do this, we will follow the roll-angle deconvolution procedures which have been developed and successfully used for imaging the dust disk around Beta Pic, and therefore should work even better for our much fainter target stars. We will use model (TinyTim) and observed PSFs to remove the PSF of the central star from the images. Extensive PSF fitting has allowed a refinement of the TinyTim PSF simulator to the point that models agree with data with a mean pixel-to-pixel error of 15\ to about 5\ is an important asset to the success of the deconvolution procedures. STIS will be used to obtain long slit medium- resolution spectra of V Hya in the lambdaLambda4051-4337Angstrom range, using G430M with a tilt setting of 4194. From the optical spectra of V Hya taken by Lloyd Evans, we estimate that the SIIlambda4066Angstrom line has an intensity of 2.3times10^-14 erg/s/cm^2/Angstrom, making the reasonable assumption that the emission is spread over 200kms along the dispersion axis, and 1arcs5 (i.e. half the size of the 4.6micron shells) along the spatial axis. Using the STIS exposure time calculator, we find that in 40 minutes, with CRSPLIT=4, we will obtain a S/N=29 per pixel with the 0arcs2 slit. A high S/N ratio is important since there may be important faint components, and because we also want to obtain good data on some of the other weaker lines in the bandpass (4051- 4337Angstrom), such as SIIlambda4074Angstrom, SrIIlambda4213Angstrom and FeIILambda4241 & 4285Angstrom. Since our most important objective is to understand the velocity field of the jets in order to study the collimation process, we will obtain spectra with 2 additional slit positions displaced symmetrically on either side of the central star (i.e. with offsets of +/- 2arcs0). We will therefore require a total of 3 orbits for the STIS observations. 9100( 11) - 05/23/03 11:26 - [ 3] Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9100( 11) - 05/23/03 11:26 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V-HYDRAE STAR, CARBON STAR RA=10H 51M 37.2546S +/- 0.1", J2000 B = 14.23 DEC=-21D 15' 0.32" +/- 0.1" V = 9.7 R = 7.8 I = 6 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 -0.00101 0.00272 0.0 2 PI1-GRU STAR, S STAR RA=22H 22M 44.2053S +/- 0.1", J2000 V = 6.1 DEC=-45D 56' 52.598" +/- 0.1" B = 8.4 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 0.00267 -0.001092 0.00654 3 BETA-GRU STAR RA=22H 42M 40.0507S +/- 0.1", J2000 V = 2.13 DEC=-46D 53' 04.477" +/- 0.1" B = 3.7 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 0.01323 -0.00451 0.01917 9100( 11) - 05/23/03 11:26 - [ 5] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 13 Primary_Pattern Secondary_Pattern Pattern_Type STIS-PERP-TO-SLIT STIS-ALONG-SLIT Pattern_Purpose MOSAIC DITHER Number_Of_Points 3 2 Point_Spacing 0.2 0.025 Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 0 90 Center_Pattern YES NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 14 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.025 Coordinate_Frame POS-TARG Pattern_Orient 90 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 9100( 11) - 05/23/03 11:26 - [ 6] Visit: 01 Visit Priority: Visit Requirements: ORIENT 125D TO 145D ORIENT 305D TO 325D On Hold Comments: Additional Comments: Slit should be oriented along E-W (i.e. PA=90) bipolar outlow (PA=90/270) with +/-10D tolerance Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 V-HYDRAE STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.1 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 11 V-HYDRAE STIS/C ACQ/PEA 52X0.2F MIRROR 1 0.2 S CD K 1-R ------------------------------------------------------------------------------------------------------------------------------------ 20 V-HYDRAE STIS/C ACCUM 52X0.2 G430M 4194 CR-SPLIT=2,GAIN=1 1 12 M PATTERN 13 CD Comments: mosaic of 3 0.2" slits, spaced 0.2" ------------------------------------------------------------------------------------------------------------------------------------ 24 V-HYDRAE STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2,GAIN=4 1 10 S PATTERN 14 CD Comments: short exposure 1 central slit ------------------------------------------------------------------------------------------------------------------------------------ 25 V-HYDRAE STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2,GAIN=4 1 30 S PATTERN 14 CD Comments: medium exposure 1 central slit ------------------------------------------------------------------------------------------------------------------------------------ 26 V-HYDRAE STIS/C ACCUM 52X0.2 G750M 6581 CR-SPLIT=2,GAIN=4 1 74 S PATTERN 13 CD Comments: long exposure, mosaic of 3 0.2" slits, spaced 0.2" ------------------------------------------------------------------------------------------------------------------------------------ 27 V-HYDRAE STIS/C ACCUM 52X0.2 G750M 7795 CR-SPLIT=2,GAIN=4 1 10 S PATTERN 14 CD Comments: short exposure 1 central slit ------------------------------------------------------------------------------------------------------------------------------------ 28 V-HYDRAE STIS/C ACCUM 52X0.2 G750M 7795 CR-SPLIT=2,GAIN=4 1 76 S PATTERN 14 CD Comments: long exposure, 1 central slit ------------------------------------------------------------------------------------------------------------------------------------ 29 CCDFLAT STIS/C ACCUM 52X0.2 G750M 7795 2 DEF CD Comments: fringe flat ------------------------------------------------------------------------------------------------------------------------------------ 9100( 11) - 05/23/03 11:26 - [ 7] Visit: 02 Visit Priority: Visit Requirements: ORIENT 280D TO 300D ORIENT 342D TO 350D On Hold Comments: Additional Comments: Selected Orientation is chosen to keep the E-W (i.e. PA=90) bipolar outflow axis away from diffraction spikes and bloom direction, i.e. within the +/- 45D wedge around the X-axis (=axis perpendicular to columns) of the PC-chip. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 V-HYDRAE WFPC2 IMAGE PC1-FIX F555W CLOCKS=NO,ATD-GAIN=15 1 0.11 S GSPAIR 0608200720F20608200685F1 Comments: max count level=39.7% of saturation for stellar peak ------------------------------------------------------------------------------------------------------------------------------------ 12 V-HYDRAE WFPC2 IMAGE PC1-FIX F555W CLOCKS=NO,ATD-GAIN=15 2 10 S Comments: Approximately 89 pixels along adjacent columns will be killed by bloom ------------------------------------------------------------------------------------------------------------------------------------ 14 V-HYDRAE WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES,ATD-GAIN=15 6 100 S Comments: Approximately 928 pixels along adjacent columns will be killed by bloom ------------------------------------------------------------------------------------------------------------------------------------ 40 V-HYDRAE WFPC2 IMAGE PC1-FIX F814W CLOCKS=NO,ATD-GAIN=15 1 0.11 S Comments: Maximum count level per pixel is 303.4% of saturation; approx. 7 pixels along adjacent CCD columns will be killed by the bloom. ------------------------------------------------------------------------------------------------------------------------------------ 42 V-HYDRAE WFPC2 IMAGE PC1-FIX F814W CLOCKS=NO,ATD-GAIN=15 1 1 S Comments: Approximately 100 pixels along adjacent CCD columns obliterated by the bloom, if I=6 ------------------------------------------------------------------------------------------------------------------------------------ 44 V-HYDRAE WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES,ATD-GAIN=15 4 30 S Comments: About 3117 pixels along adjacent CCD columns will be obliterated by bloom, if I=6 ------------------------------------------------------------------------------------------------------------------------------------ 9100( 11) - 05/23/03 11:26 - [ 8] Visit: 03 Visit Priority: 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 PI1-GRU ACS/HR ACQ HRC-ACQ F502N 1 2.0 S C Comments: ACQ FOR CORON1.8 ------------------------------------------------------------------------------------------------------------------------------------ 15 PI1-GRU ACS/HR ACCUM HRC-COR F475W CR-SPLIT=3 1 1899.0 USE OFFSET 9100-1 C ON1.8 S ------------------------------------------------------------------------------------------------------------------------------------ 20 PI1-GRU ACS/HR ACCUM HRC-COR F606W CR-SPLIT=2 1 500.0 S USE OFFSET 9100-1 C ON1.8 ------------------------------------------------------------------------------------------------------------------------------------ 9100( 11) - 05/23/03 11:26 - [ 9] Visit: 04 Visit Priority: Visit Requirements: ORIENT 20D TO 30D FROM 2 On Hold Comments: Additional Comments: Orient chosen to allow telescope artifacts to remain fixed, and source structure to rotate on chip by 20 TO 30 degrees. Please keep the same guide stars for both rolls (VISITS 2 and 4) if possible. If not possible, please contact PI (Sahai) to determine a compromise roll. We want to keep the star from shifting location on the detector after a roll, and going to new guide stars can introduce such shifts (because of uncertainties in the GSC positions). Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 V-HYDRAE WFPC2 IMAGE PC1-FIX F555W CLOCKS=NO,ATD-GAIN=15 1 0.11 S GSPAIR 0608200720F20608200685F1 Comments: max count level=39.7% of saturation for stellar peak ------------------------------------------------------------------------------------------------------------------------------------ 12 V-HYDRAE WFPC2 IMAGE PC1-FIX F555W CLOCKS=NO,ATD-GAIN=15 2 10 S Comments: Approximately 89 pixels along adjacent columns will be killed by bloom ------------------------------------------------------------------------------------------------------------------------------------ 14 V-HYDRAE WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES,ATD-GAIN=15 6 100 S Comments: Approximately 928 pixels along adjacent columns will be killed by bloom ------------------------------------------------------------------------------------------------------------------------------------ 40 V-HYDRAE WFPC2 IMAGE PC1-FIX F814W CLOCKS=NO,ATD-GAIN=15 1 0.11 S Comments: Maximum count level per pixel is 303.4% of saturation; approx. 7 pixels along adjacent CCD columns will be killed by the bloom. ------------------------------------------------------------------------------------------------------------------------------------ 42 V-HYDRAE WFPC2 IMAGE PC1-FIX F814W CLOCKS=NO,ATD-GAIN=15 1 1 S Comments: Approximately 100 pixels along adjacent CCD columns obliterated by the bloom, if I=6 ------------------------------------------------------------------------------------------------------------------------------------ 44 V-HYDRAE WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES,ATD-GAIN=15 4 30 S Comments: About 3117 pixels along adjacent CCD columns will be obliterated by bloom, if I=6 ------------------------------------------------------------------------------------------------------------------------------------ 9100( 11) - 05/23/03 11:26 - [ 10] Visit: 05 Visit Priority: Visit Requirements: SEQ 3, 5 WITHIN 1.9H 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 ------------------------------------------------------------------------------------------------------------------------------------ 40 BETA-GRU ACS/HR ACQ HRC-ACQ F220W, 1 7.0 S C F606W Comments: ACQ FOR CORON1.8 ------------------------------------------------------------------------------------------------------------------------------------ 50 BETA-GRU ACS/HR ACCUM HRC-COR F475W CR-SPLIT=NO 1 30.0 S USE OFFSET 9100-2 C ON1.8 ------------------------------------------------------------------------------------------------------------------------------------ 55 BETA-GRU ACS/HR ACCUM HRC-COR F475W CR-SPLIT=2 1 120.0 S USE OFFSET 9100-2 C ON1.8 ------------------------------------------------------------------------------------------------------------------------------------ 58 BETA-GRU ACS/HR ACCUM HRC-COR F475W CR-SPLIT=3 1 1230.0 USE OFFSET 9100-2 C ON1.8 S ------------------------------------------------------------------------------------------------------------------------------------ 60 BETA-GRU ACS/HR ACCUM HRC-COR F606W CR-SPLIT=NO 1 6.0 S USE OFFSET 9100-2 C ON1.8 ------------------------------------------------------------------------------------------------------------------------------------ 65 BETA-GRU ACS/HR ACCUM HRC-COR F606W CR-SPLIT=2 1 25.0 S USE OFFSET 9100-2 C ON1.8 ------------------------------------------------------------------------------------------------------------------------------------ 68 BETA-GRU ACS/HR ACCUM HRC-COR F606W CR-SPLIT=2 1 600.0 S USE OFFSET 9100-2 C ON1.8 ------------------------------------------------------------------------------------------------------------------------------------ 9100( 11) - 05/23/03 11:26 - [ 11] Summary Form for Proposal 9100 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.2F1-R 52X0.2 PC1-FIX HRC-ACQ HRC-CORON1.8 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD WFPC2 ACS/HRC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT GAIN=1 GAIN=4 CR-SPLIT=2 ATD-GAIN=15 CLOCKS=NO CLOCKS=YES CR-SPLIT=3 CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 125D TO 145D ORIENT 305D TO 325D PATTERN 13 PATTERN 14 ORIENT 280D TO 300D ORIENT 342D TO 350D GSPAIR 0608200720F20608200685F1 USE OFFSET 9100-1 ORIENT 20D TO 30D FROM 2 SEQ 3, 5 WITHIN 1.9H USE OFFSET 9100-2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G430M G750M F555W F814W F502N F475W F606W F220W,F606W ------------------------------------------------------------------------------------------------------------------------------------ Target Names V-HYDRAE CCDFLAT PI1-GRU BETA-GRU ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 4194 6581 7795 ------------------------------------------------------------------------------------------------------------------------------------