Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5404 Report Date: 18-Jul-95:17:18 Version: ********** Check-in Date: ********** 1.Proposal Title: NARROW-BAND IMAGING OF HYDROGEN-POOR PLANETARY NEBULAE CYCLE 4 HIGH ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID INTERSTELLAR MEDIUM GO Sub Category PLANETARY NEBULAE ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Patrick J Harrington 2620 USA 301-405-1517 ------------------------------------------------------------------------------------ 7. Abstract There is an exceptional group of PNe with nebular gas that consists of nearly undiluted products of nuclear burning. These hydrogen-poor PNe are thought to result when a final helium shell flash occurs after the complete removal of the hydrogen envelope. Four of the five currently known H-poor PNe are Cycle 2 HST spectroscopic targets. Complementary [O III] 5007 HST imaging of two nebulae has revealed remarkable `cometary' structures, consisting of compact (0".15 - 0".5) knots with radial tails several arcsec in length. We interpret this morphology in terms of dense H-poor condensations whose outer expanding layers are swept outwards by mass- loaded stellar winds. We propose narrow-band (He I, He II, and [O III]) imaging of these cometary structures in A30, and [O III] imaging of two remaining H-poor PNe where such dynamical structures are expected. These images are crucial for interpreting UV spectra of H-poor PNe. Optical imaging combined with UV data will provide fundamental information: (1) on helium-burning nucleosynthesis, by determining the ionic concentrations of H and He burning products; (2) on the interaction of the several thousand km/sec stellar winds with the nearby clumps of nebular material, resulting in mass-loaded outflows; (3) on the ram-pressure stripping of a H-poor PN in the globular cluster M22 by the interstellar medium; (4) on physics of very dusty H-poor gas, with grain photoelectrons dominating energy balance. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.77 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5404 PI: Patrick J Harrington Proposal Title: NARROW-BAND IMAGING OF HYDROGEN-POOR PLANETARY NEBULAE CYCLE 4 HIGH ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Patrick J Harrington 2620 USA Kazimierz J Borkowski 2620 USA Zlatan I Tsvetanov 2380 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We plan to obtain WFPC2 images in [OIII] 5007, HeII 4686 and HeI 5878 of A30 as well as [OIII] 5007 images of the M22 PN (IRAS18333-2357) and IRAS15154-5258. In all cases the central star will be placed in the center of the PC chip, so that most or even all of the inner part of the PNe is imaged at the highest possible resolution. Part of the outer structure of A30 will fall onto the WFC chips (depending upon the exact orientation). We will not use CR split since we are taking several images, which then can be combined to clean the cosmic ray events. Exposure times are set with the requirement not to saturate the central star, which will allow us to penetrate as close as possible to it. The star, however, will be numerically saturated. Long integration time is very important, since we want to achieve as high as possible signal-to-noise ratio in the spatially extended structure. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. Our goal is to obtain narrow-band images of H-poor PNe with the spatial resolution limited only by the HST optics. This super-resolution is essential for achieving objectives presented in the scientific justification for this proposal. The basic reason for this is the presence of small-scale structures in H-poor nebulae which are not resolved (or resolved in only one direction) in ground- based images of our targets obtained in sub-arcsecond seeing. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The essense of this program is to penetrate as close as possible to the central star at the highest spatial resolution of WFPC2. Therefore, we will not use the CR-SPLIT option, and we will take instead several images in each filter, which will then be combined to clean up the cosmic ray events. The exposure times are calculated to avoid physical saturation (image "blooming") of the central stars in A30 and IRAS18333-2357. However, these two central stars will be saturated numerically. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. We have no special calibration requirements. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. Page 3 ------------------------------------------------------------------------------------ 9. Description of previous HST work. We have been involved in the following HST projects: No. 2266: Post-Asymptotic Giant Branch Evolution in the Magellanic Clouds, PI M.A. Dopita, P. Harrington is a Co-I. Not related beyond the fact that both deal with planetary nebulae. No. 3671, 4226: Ultraviolet Spectroscopy of Hydrogen-Poor Planetary Nebulae, PI P. Harrington, K. Borkowski and Z. Tsvetanov are Co-I, cycle 2. Related. Split into two parts for technical reasons. No. 4371: FOS spectroscopy of resolved structure in the nucleus of Mrk 3. PI Tsvetanov, cycle 3. Not related to this proposal. No. 4503: Absorption line spectra of Seyfert galaxies. PI Kriss, Z.Tsvetanov is Co-I, cycle 3. Not related to this proposal. No. 4668: FOS spectroscopy of NGC1052 and NGC4258. PI Ford, Z.Tsvetanov is Co-I, cycle 3. Not related to this proposal. No. Z570: Collimated radio and ionizing radiation in NGC5252. PI Z.Tsvetanov, cycle 4. Not related to this proposal. Recent unexpected results from our HST project No.3671 prompted us to ask for high spatial resolution imaging in this proposal. This would complement our Cycle 2 HST program concentrated on UV spectroscopy, allowing us to take the full advantage of the HST capabilities in studying these unique objects. The primary objective of our Cycle 2 project is to determine the chemical abundances of H and He burning products, from C to Mg. Our complementary short (15 min) [OIII] 5007 FOC images of A30 and A78 revealed that H-poor gas is concentrated in remarkable `cometary' structures (Borkowski, Harrington, & Tsvetanov 1993, ApJ, 415, L47). Most of them consist of compact (0.15" - 0.5") knots with radial tails several arcsec in length. Both stars have energetic winds which are responsible for the knot morphology. These `cometary' structures are not visible in our UV FOC images of A30 and A78. Instead, we detected extended emission concentrated around central stars, mostly interior of the optical knots. We interpret this emission in terms of mass-loaded stellar winds, heated mostly by photoelectric emission from dust grains. We have also obtained an FOC image of LMC26, a candidate for H-poor PN in the Large Magellanic Cloud, and obtained ground-based images and spectra. An analysis of this peculiar object is in progress, but it appears that chemical abundances are those typical for LMC PNe. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). The Department of Astronomy of the University of Maryland has an extensive network of Sun workstations, including a number of Sparc X's. This network and supporting technical staff provides an excellent environment for data reduction and modeling. ------------------------------------------------------------------------------------ 11. Address Information Name: PATRICK J HARRINGTON Category: PI Institution: 2620 Address: DEPARTMENT OF ASTRONOMY UNIVERSITY OF MARYLAND City: COLLEGE PARK State: MD Zip Code: 20742 Country: USA Telephone: 301-405-1517 Telex (or e-mail): jph@astro.umd.edu ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5404 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 PK208+33D1 G,502 PLATE-ID=0204, 2000 V=+10 1 V=14.30+/- ABELL30 RA = 8H 46M 53.46S +/- 2 0.01,TYPE=OVI,A(V)=0.90+/-0.10 GSC1396-1621 0.02S, 3 SURF-LINE(5007) = 1.5 +/- 0.5 E-12 DEC = +17D 52' 45.7" +/- 4 W-LINE(5007) = 0.17 +/- 0.03 0.3" 5 SURF-LINE(4686) = 2.4 +/- 1.5 E-13 6 W-LINE(4686) = 0.17 +/- 0.03 7 SURF-LINE(5878) = 8 +/- 4 E-14 W-LINE(5878) = 0.17 +/- 0.03 Comments: FLUXVAL_1 REFERS TO CENTRAL STAR. ------------------------------------------------------------------------------------------------------------------------------------ 2 IRAS1833- G,502 RA = 18H 36M 22.78S +/- 2000 V = -153 1 V=14.3+/-0.2,TYPE=O,A(V)=1.5+/- 2357 0.02S, 2 0.15 DEC = -23D 55' 19.26" +/- 3 SURF-LINE(5007) = 3 +/- 2 E-14 0.3", W-LINE(5007) = 0.17 +/- 0.03 PLATE-ID=067T Comments: FLUXVAL_1 REFERS TO CENTRAL STAR. LINE INFORMATION FOR EMISSION KNOTS ------------------------------------------------------------------------------------------------------------------------------------ 3 IRAS15154- G,502 RA = 15H 19M 08.62S +/- 2000 V=0 1 V=16.2+/-0.2 5258 0.02S, 2 SURF-LINE(5007) = 5 +/- 3 E-14 DEC = -53D 09' 52.2" +/- 3 W-LINE(5007) = 0.17 +/- 0.03 0.3", PLATE-ID=00H6 Comments: FLUXVAL_1 REFERS TO CENTRAL STAR. LINE INFORMATION FOR EMISSION KNOTS ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5404 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1.1 PK208+33D1 WFPC2 IMAGE PC1-FIX F502N 5007 CR-SPLIT=NO 4 900S 170 2 1 CYCLE 4 48M 3 Comments: FOUR [OIII]5007 IMAGES. CENTRAL STAR WILL BE NUMERICALLY SATURATED. ------------------------------------------------------------------------------------------------------------------------------------ 1.2 PK208+33D1 WFPC2 IMAGE PC1-FIX F469N CR-SPLIT=NO 4 900S 4 1 CYCLE 4 5 SAME POS FOR 1.2- 1.3 AS 1.1 Comments: FOUR HEII4686 IMAGES. CENTRAL STAR WILL BE NUMERICALLY SATURATED. ------------------------------------------------------------------------------------------------------------------------------------ 1.3 PK208+33D1 WFPC2 IMAGE PC1-FIX F588N CR-SPLIT=NO 4 500S 6 1 CYCLE 4 7 Comments: FOUR HEI5878 IMAGES. CENTRAL STAR WILL BE NUMERICALLY SATURATED. ------------------------------------------------------------------------------------------------------------------------------------ 2.1 IRAS1833- WFPC2 IMAGE PC1-FIX F502N 5007 CR-SPLIT=NO 4 900S 170 2 2 CYCLE 4 2357 48M 3 Comments: FOUR [OIII]5007 IMAGES. CENTRAL STAR WILL BE NUMERICALLY SATURATED. ------------------------------------------------------------------------------------------------------------------------------------ 3.1 IRAS15154- WFPC2 IMAGE PC1-FIX F502N CR-SPLIT=DEF 1 2900S 2 3 CYCLE 4 5258 CR- 3 TOLERANCE=0.1 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5404 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO CR-SPLIT=DEF CR-TOLERANCE=0.1 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.77 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category PLANETARY NEBULAE ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4; SAME POS FOR 1.2-1.3 AS 1.1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F502N F469N F588N ------------------------------------------------------------------------------------------------------------------------------------ Target Names PK208+33D1 ABELL30 GSC1396-1621 IRAS1833-2357 IRAS15154-5258 ------------------------------------------------------------------------------------------------------------------------------------