Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4940c Report Date: 09-May-96:20:11 Version: ********** Check-in Date: ********** 1.Proposal Title: POST ASYMPTOTIC GIANT BRANCH EVOLUTION IN THE MAGELLANIC CLOUDS - IMAGING: CYCLE 3 HIGH ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID INTERSTELLAR MEDIUM GO 3 Long Term yrs 2266 Sub Category PLANETARY NEBULAE ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Michael A Dopita MT. STROMLO AND SIDING SPRIN ------------------------------------------------------------------------------------ 7. Abstract Planetary Nebulae (PN) represent a critical stage of stellar evolution which is relatively poorly understood. More reliable observational estimates of stellar luminosity, mass, effective temperature, and age are required to constrain evolutionary models and determine mass-loss rates, He shell flash phases, and the role of dredge-up. This proposal represents the continuation of our systematic and definitive study with HST of a large sample of nebulae at known distance in the Magellanic Clouds and requires approximately 50 hours for completion. All parameters needed for confrontation of theory with observation can be derived from direct PC imaging and FOS spectra in the 1150-3200A range. The images give spatial structure, sizes, ionized mass, dynamical ages, and an estimate of the final mass-loss rate on the AGB. The spectra will be combined with the images and with stellar atmospheric and evolutionary models to derive the effective temperature, luminosity, and core mass of each of the exciting stars. These data will define the evolutionary status of each of the PN observed. We will use two independent ionization codes to interpret the spatial structure derived from PC images and the FOS data, in conjuction with optical and IR spectra. This analysis will also yield chemical abundances of many elements, including the astrophysically important species He, C, N, O, and Si. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 4.51 par: 0 10. Num targs pri: 7 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4940c PI: Michael A Dopita Proposal Title: POST ASYMPTOTIC GIANT BRANCH EVOLUTION IN THE MAGELLANIC CLOUDS - IMAGING: CYCLE 3 HIGH ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Michael A Dopita MT. STROMLO AND SIDING SPRING AUSTRALIA OBSERVATORIES Stephen J Meatheringham MT. STROMLO AND SIDING SPRING AUSTRALIA OBSERVATORIES Peter R Wood MT. STROMLO AND SIDING SPRING AUSTRALIA OBSERVATORIES Ralph C Bohlin STSCI USA Holland C Ford STSCI USA Emanuel Vassiliadis STSCI USA Patrick J Harrington UNIVERSITY OF MARYLAND USA Theodore P Stecher NASA GODDARD SPACE FLIGHT CENTER USA Stephen P Maran NASA GODDARD SPACE FLIGHT CENTER USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. Imaging Program: The Magellanic Cloud PN range in size from 0.05 - 4.0 arcseconds, with a typical size of about 0.6 arcseconds (Jacoby 1980; Wood, Bessell and Dopita 1986; Wood et. al. 1987). Consequently, they are ideally suited for imaging with the PC camera. Our Cycle 3 [O III] 5007 Angstrom (F502N) images are designed to give a typical signal to noise of 20 per pixel to provide data on angular diameters and nebular morphology (spherical,bipolar, multiple shell, etc.), which in conjunction with our ground-based [O III] expansion velocity measurements will provide a dynamical age model. Cycle 3 UV Spectrophotometry: We are undertaking in Cycle 3 FOS spectrophotometry in the range 1150 - 3200 Angstroms using the G130H and G190H gratings, and the PRISM. These observations are described more fully in a separate proposal. The Cycle 3 imaging program needs to be executed first to determine the individual FOS acquisition methods. References: Jacoby, G., 1980, Ap. J. Suppl. Ser.,42, p. 1 Wood, P.R., Bessell, M.S., and Dopita, M.A., 1986, Ap. J.,311, p. 632 Wood, P.R., Meatheringham, S.J., Dopita, M.A., and Morgan, D.H., 1987, Ap. J., 320, p. 178 ###### The program ID which uses these early acq's for follow up spectroscopy is 4566. Page 3 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The angular diameters of the Magellanic Cloud PN lie in the range 0.05 - 4.0 arcseconds, ideally suited to the HST capabilities. The dimensions or morphologies of these objects cannot, in general, be obtained from the ground. Preliminary ground-based work has been done, as far as it is possible, using direct imaging and image reconstruction (Jacoby 1980; Wood et. al. 1987) or speckle interferometry (Wood, Bessell, and Dopita 1986). However, imaging resolves only the largest, and speckle interferometry resolves only the brightest nebulae, leaving the vast majority of objects unresolved. These observations are essential in determining the method of acquistion to be used in the subsequent Cycle 3 FOS observations. Our HST program is supported by a comprehensive and continuing ground-based program. We have used the 1-metre, 2.3-metre and 3.9- metre telescopes at Siding Spring to measure fluxes, sizes, expansion velocities, radial velocities and nebular spectra from 3200 to 10000 Angstroms. These observations already provide an excellent set of homogeneous and high-quality data which gives the best possible ground-based characteristics of the Magellanic Cloud population of PN. this data set will allow us to extend our population classifications from the HST subset to the entire population of PN in the Magellanic Clouds. References: See question 3. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. An high-quality astrometric determination of the nebular centroid will be obtained on the basis of the PC images, we may seek to give an improved estimate of the position based on these data, for input to the Cycle 3 FOS spectroscopy program. Based on our experience with our Cycle 2 FOS exposures, the imaging program must be completed first to allow a proper determination of the method of FOS acquistion. This is an EARLY ACQ proposal and needs to be executed sufficiently early for the FOS spectroscopy to be completed before the end of Cycle 3. ###### Proposal to later use these early acq's for spectroscopy is 4566. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. The PC exposures have been arranged in SEQUENCE, where a PSF exposure will be executed at the beginning, the middle, and the end of this sequence. From attempts at deconvolution of Cycle 1 PC images, this arrangement of PSF exposures should aid us in deconvolving the Cycle 3 PC images. Page 4 ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. All PC images and FOS spectra will be reduced at STScI and then distributed by H.Ford and R.Bohlin to the team members. The dynamical ages of the nebulae will be derived by creating models of expanding prolate shells with varying azimuthal intensities whose projections onto the sky reproduce the [O III] line profiles (already obtained for the whole sample, Dopita et. al. 1985, 1988) and the PC image structure. The software needed for this program has already been written by H.Ford and his collaborators. We plan to combine the FOS UV spectrophotometry with ground-based and near-IR spectrophotometry to produce dereddened spectra. Theoretical models of the nebular continuum and of the central star will be used to separate the two continuum contributions and to place the star on the L-T(eff) diagram. By using the dynamical age already obtained, we will compare the evolutionary tracks implied for the PN nuclei with the theoretical evolutionary models (e.g. Wood and Faulkner 1986). This will enable us to determine the mass distribution of the PN nuclei, to determine whether PN ejection occurs at the time of the Helium shell flash, and to put strong observational restraints on the post-AGB mass-loss. Using the observed parameters of the central star, the FOS spectrophotometry and ionisation structure implied by the PC images, we will construct detailed photoionisation models using independent codes by Harrington, and by Dopita and Binette. The nebular size and structure, the shape of the stellar spectrum, and the ratio of stellar to nebular continua will enable us to obtain the mean ionisation parameter (Q), the ionisation temperature (T*), and the optical thickness of the nebula, which together define the nebular model. The FOS spectra are vital in the determination of the abundances of the dominant ionic species of N, C and Si. Likewise the ratio of the C III] doublet at 1906, 1909 Angstroms will give the electron density in the region of the PN containing the dominant ionisation stage. From the complete spectrophotometric data we will be able to derive the abundances of the elements : He, C, N, O, Ne, S, Cl, and Ar and possibly, Mg, Fe and Ni as well. We wish to stress that the PC nebular images and the wealth of FOS ultraviolet data will enable us to construct models with a level of detail which has previously been obtained in only a few Galactic PN such as NGC7662 (Harrington et. al. 1982), and IC3918 (Clegg et. al. 1987). References: Clegg, R.E.S., Harrington, J.P., Barlow, M.J., and Walsh, J.R., 1987, Ap. J. vol. 314, p. 575 Dopita, M.A., Ford, H.C., Lawrence, C.J., and Webster, B.L.,1985, Ap. J. vol. 296, p. 390 Dopita, M.A., Meatheringham, S.J., Webster, B.L., and Ford, H.C.,1988, Ap. J. vol. 327, p. 639 Harrington, J.P., Seaton, M.J., Adams, S., and Lutz, J.H., 1982, M.N.R.A.S., vol. 199, p. 517 Wood, P.R., and Faulkner, D.J., 1986, Ap. J., vol. 307, p. 659 ------------------------------------------------------------------------------------ 8. Additional comments or special requests. Since the full analysis of the data will take a total of three years, we request that release of the data be delayed a full year after the completion of the observational program. Full archival use will be made of data obtained under the GTO program on Magellanic Cloud PN as this is released. Primary team responsibilities are as follows: 1. Image reduction, astrometry, analysis and distribution : Ford and Bohlin. 2. FOS data reduction and distribution : Bohlin and Meatheringham 3. Analysis and evolution of central stars : Dopita, Wood, Bohlin, Maran and Stecher 4. Nebular modelling and chemical composition : Dopita, Harrington, and Maran 5. Analysis of stellar populations and astrophysical interpretation : all team. ------------------------------------------------------------------------------------ 9. Description of previous HST work. As described above, this project was awarded time for HST imaging in Cycle 1. One object remains to be observed from this program: two attempts to observe this final object have failed due to Guide Star acquistion failures. All completed observations are currently being deconvolved. The completed Cycle 1 images have also been analysed to determine the best FOS acquisition method in Cycle 2. The Cycle 2 observations are currently being scheduled. Page 5 ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). The manpower, fiscal and hardware resources necessary to support the work of the P.I. and the other Australian members of this group will be supplied from within the internal budget of MSSSO as necessary. Funding will also be available to support any short overseas visits that may be necessary to coordinate activities of the various team members, as summarised in question 8. ------------------------------------------------------------------------------------ 11. Address Information Name: MICHAEL A DOPITA Category: PI Institution: Mt. Stromlo and Siding Spring Obs Address: PRIVATE BAG WESTON CREEK P.O. City: WESTON State: Zip Code: ACT 2611 Country: AUSTRALIA Telephone: (011 61) 6 2490212 Telex (or e-mail): AA62270 ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4940c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 101 SMC-SMP22 H,502 RA = 00H 58M 37.22S +/- 2000.0 V = 153 1 F-CONT(1650) = 1.8 +/- 0.8 E-15 N67 LN333 0.02S, 2 F-LINE(1666) = 1.9 +/- 0.6 E-14 DEC = -71D 35' 48.79" +/- 3 F-LINE(5007) = 3.8 +/- 0.1 E-13 0.1" 4 SURF-LINE(5007) = 3.0 +/- 1.0 E-12 5 W-LINE(5007) = 1.0, SIZE = 0.4 Comments: FOR ALL TARGETS, IDENT # FROM FOLLOWING REFS: SMP=SANDULEAK ETAL.1978.PASP 90,621 N = HENIZE 1956. AP J. SUPPL. 2,315 LN = LINDSAY 1961. ASTR. J. 66, 169 A MORE ACCURATE POSITION OF PN MAY BE DETERMINED FROM PC IMAGE ------------------------------------------------------------------------------------------------------------------------------------ 102 LMC-SMP7 H,502 RA = 04H 48M 29.64S +/- 2000.0 V = 220 1 F-CONT(1650) = 7.6 +/- 0.8 E-16 N177F 0.02S, 2 F-LINE(1666) = 4.5 +/- 0.6 E-14 DEC = -69D 08' 13.24" +/- 3 F-LINE(5007) = 8.9 +/- 0.1 E-13 0.1" 4 SURF-LINE(5007) = 9.3 +/- 1.0 E-13 5 W-LINE(5007) = 1.0, SIZE = 1.1 ------------------------------------------------------------------------------------------------------------------------------------ 103 LMC-SMP37 H,502 RA = 05H 11M 03.00S +/- 2000.0 V = 270 1 F-CONT(1650) = 1.9 +/- 0.8 E-15 N28 0.02S, 2 F-LINE(1666) = 7.8 +/- 0.6 E-14 DEC = -67D 47' 59.55" +/- 3 F-LINE(5007) = 1.6 +/- 0.1 E-12 0.1" 4 SURF-LINE(5007) = 1.3 +/- 1.0 E-11 5 W-LINE(5007) = 1.0, SIZE = 0.4 ------------------------------------------------------------------------------------------------------------------------------------ 104 LMC-SMP61 H,502 RA = 05H 24M 35.97S +/- 2000.0 V = 193 1 F-CONT(1650) = 2.1 +/- 0.6 E-14 N203 0.02S, 2 F-LINE(1666) = 1.5 +/- 0.3 E-13 DEC = -73D 40' 39.68" +/- 3 F-LINE(5007) = 2.9 +/- 0.1 E-12 0.1" 4 SURF-LINE(5007) = 1.5 +/- 1.0 E-11 5 W-LINE(5007) = 1.0, SIZE = 0.5 ------------------------------------------------------------------------------------------------------------------------------------ 105 LMC-SMP67 H,502 RA = 05H 29M 15.75S +/- 2000.0 V = 289 1 F-CONT(1650) = 2.0 +/- 0.6 E-14 N53 0.02S, 2 F-LINE(1666) = 2.7 +/- 0.6 E-14 DEC = -67D 32' 47.58" +/- 3 F-LINE(5007) = 5.4 +/- 0.1 E-13 0.1" 4 SURF-LINE(5007) = 2.8 +/- 1.0 E-12 5 W-LINE(5007) = 1.0, SIZE = 0.5 ------------------------------------------------------------------------------------------------------------------------------------ 106 LMC-SMP101 H,502 RA = 06H 23M 40.39S +/- 2000.0 V = 281 1 F-CONT(1650) = 2.1 +/- 0.8 E-15 0.02S, 2 F-LINE(1666) = 7.3 +/- 0.6 E-14 DEC = -69D 10' 38.35" +/- 3 F-LINE(5007) = 1.5 +/- 0.1 E-12 0.1" 4 SURF-LINE(5007) = 1.3 +/- 1.0 E-12 5 W-LINE(5007) = 1.0, SIZE = 1.2 ------------------------------------------------------------------------------------------------------------------------------------ 107 LMC-PSF-STAR H,704 RA = 05H 40M 34.45S +/- 2000.0 1 V = 13.1 +/- 0.4 0.02S, DEC = -66D 17' 23.11" +/- 0.1" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4940c [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 DEFINE # PC IMAGE # # READ=YES 1 1S # 1 CYCLE 3 / 1.0-16.5 PCEXP CR-SPLIT=DEF PRE-FLASH=YES Comments: ALL SUBSEQENT PC EXPOSURES ARE EARLY ACQ FOR FOS OBSERVATIONS TO FOLLOW IN CYCLE 3, PROPOSAL ID 4566. ------------------------------------------------------------------------------------------------------------------------------------ 2 DEFINE # PC IMAGE # # READ=YES 1 1S # 1 PCMEX CR-SPLIT=DEF PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 10.5 USE LMC-PSF- PC6 F502N X800 130 1 NON-INT PCMEX STAR Comments: OBSERVATION OF CALIBRATION STAR TO OBTAIN LOCAL PSF. BEGIN SEQUENCE OF PC EXPOSURES TO LATER AID FOS ACQUISITIONS. ------------------------------------------------------------------------------------------------------------------------------------ 11 USE SMC-SMP22 PC6 F502N X400 15 3 NON-INT PCEXP ------------------------------------------------------------------------------------------------------------------------------------ 12 USE LMC-SMP7 PC6 F502N X800 15 3 NON-INT PCEXP ------------------------------------------------------------------------------------------------------------------------------------ 13 USE LMC-SMP37 PC6 F502N X100 15 3 NON-INT PCEXP ------------------------------------------------------------------------------------------------------------------------------------ 13.5 USE LMC-PSF- PC6 F502N X800 130 1 NON-INT PCMEX STAR Comments: OBSERVATION OF CALIBRATION STAR TO OBTAIN LOCAL PSF. ------------------------------------------------------------------------------------------------------------------------------------ 14 USE LMC-SMP61 PC6 F502N X180 15 3 NON-INT PCEXP ------------------------------------------------------------------------------------------------------------------------------------ 15 USE LMC-SMP67 PC6 F502N X500 15 3 NON-INT PCEXP ------------------------------------------------------------------------------------------------------------------------------------ 16 USE LMC-SMP101 PC6 F502N X700 15 3 NON-INT PCEXP ------------------------------------------------------------------------------------------------------------------------------------ 16.5 USE LMC-PSF- PC6 F502N X800 130 1 NON-INT PCMEX STAR Comments: OBSERVATION OF CALIBRATION STAR TO OBTAIN LOCAL PSF. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4940c [ 8] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations PC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters READ CR-SPLIT PRE-FLASH ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 4.51 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category PLANETARY NEBULAE ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 3 / 1.0-16.5 NON-INT; NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements # F502N ------------------------------------------------------------------------------------------------------------------------------------ Target Names SMC-SMP22 N67 LN333 LMC-SMP7 N177F LMC-SMP37 N28 LMC-SMP61 N203 LMC-SMP67 N53 LMC-SMP101 LMC-PSF-STAR ------------------------------------------------------------------------------------------------------------------------------------