5864( 0) - 07/18/95 18:21 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5864 Version: ********** Check-in Date: ********** 1.Proposal Title: MASS LOADING OF STELLAR WINDS IN HYDROGEN -POOR PLANETARY NEBULAE ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Interstellar Medium GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: J. Patrick Harrington University of Maryland CoI: Kazimierz Borkowski Goddard Space Flight Center N CoI: Zlatan Tsvetanov Johns Hopkins University N ------------------------------------------------------------------------------------ 6. Abstract HST observations of several members of the small group of PNe with hydrogen-poor ejecta have disclosed remarkable features created by the interaction of the fast winds of the central stars with the clumpy nebular gas. We can see how dense clumps of material, left within an expanding bubble blown by a stellar wind, are being photoevaporated by the stellar radiation and then swept back and accelerated by the wind. This accelerated material mixes with the wind, slowing it and increasing its density. Thus these rare PNe open a unique window on mass loading processes. We propose to extend WFPC2 imaging and GHRS spectroscopy of H-poor PNe in order to understand the interaction of a stellar wind with the inhomogeneous ambient medium, to understand the mass loading process, measure its strength, and find how nebular material is accelerated to high velocities by the stellar wind. ------------------------------------------------------------------------------------ 5864( 0) - 07/18/95 18:21 - [ 2] Observations Description ------------------------ o WFPC2 OBSERVATIONS We plan to obtain WFPC2 images in OIII Lambda5007, HeII Lambda4686 and HeI Lambda5878 of A78 as well as an H Alpha image of IRAS15154- 5258. In all cases the central star will be placed in the center of the PC chip, so that all of the inner part of the PNe is imaged at the highest possible resolution. Part of the outer structure of A78 will fall onto the WFC chips (depending upon the exact orientation). Exposure times for A78 can be based our WFPC2 images of A30 in the corresponding filters. This can be done because we can see from our Cycle 2 FOC images that the nebulosity in the two objects is of comparable brightness, with the exception that the bright polar knots of A30 have no analog in A78. For A30 we used exposures of 48, 60, and 30 min for O III, He II, and He I respectively. Each of these was split into 4 parts to avoid (physical) saturation of the central star. In the case of A78, the star is a magnitude brighter, so that is not practical to break the exposures into very small bits -- we can tolerate some saturation. The intial guide star aquisition and the 30 min exposure with the He I filter will occupy the first orbit. The He II image and the O III image will then require three orbits together. Thus we require a total of four orbits for A78. Our O III image of IRAS15154-5258 (Fig. 2) required 40 min. Our ground-based spectra indicate that H Alpha is weaker than 5007Angstrom by a factor of 7. But the sensitivity of the WFPC2 is higher at H Alpha is, as is the filter transmission, so the time to reach the same counts in H Alpha would be 120 min. We feel that we can tolerate a lower S/N than we have in O III and thus we request two orbits (~ 90 min) for this object. o GHRS OBSERVATIONS We plan to observe A78 with the G140M grating of the GHRS in the vicinity of the N V Lambda1241 line. The simplest way to estimate our exposure is by comparison with our observations of the same object in the vicinity of C IV Lambda1550. That exposure was 30 min, and gave a adequate S/N (Fig. 4). From IUE spectra we know that the stellar continuum at 1241Angstrom is about 1.8 times higher than at 1550Angstrom. The sensitivity of HRS G160M is nearly the same at these two wavelengths, and the G140M sensitivity at Lambda1241 is comparable to G160M. However, the C IV exposure used the SSA, which lost half the light due to spherical aberration. Thus the new HST should be able to reach the same continuum S/N in about 9 min. However, we expect the N V absorption lines have smaller optical depths than C IV, and thus we will actually need better S/N. We propose to use the rest of the orbit, which, with target aquisition, will leave over 20 min for the exposure. Real Time Justification ----------------------- We have made concentrated efforts to study H-poor PNe with ground-based instruments in different wavelength ranges. Many of these observations have been obtained and they are being analyzed, including optical spectroscopy, imaging and spectropolarimetric observations of IRAS 15154-5258. All H- poor objects are strong infrared emitters because of the high dust content -- we do hope to learn more about the dust in these objects once the ISO satellite becomes operational. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5864( 0) - 07/18/95 18:21 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5864( 0) - 07/18/95 18:21 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PK81-14D1 ISM, PLANETARY NEBULA RA=21H 35M 29.39S +/- 0.02S, 2000 V = +17 V=13.25+/-0.01 DEC=+31D 41' 46.0" +/- 0.3", A(V)=0.46+/-0.10 PLATE-ID=0054 SURF-LINE(5007) = 1.5 +/- 0.5 E-12 W-LINE(5007) = 0.17 +/- 0.03 SURF-LINE(4686) = 2.4 +/- 1.5 E-13 W-LINE(4686) = 0.17 +/- 0.03 SURF-LINE(5876) = 8 +/- 4 E-14 W-LINE(5876) = 0.17 +/- 0.03 2 PK81-14D1- STAR, PLANETARY NEBULA RA=21H 35M 29.39S +/- 0.02S, 2000 V = +17 V=13.25+/-0.01 CENTRAL-STAR CENTRAL STAR DEC=+31D 41' 46.0" +/- 0.3", A(V)=0.46+/-0.10 PLATE-ID=0054 F-CONT(1241)= 18 +/- 5 E-13 3 IRAS15154- ISM, PLANETARY NEBULA RA=15H 19M 08.62S +/- 0.02S, 2000 V=0 V=16.2+/-0.2 5258 DEC=-53D 09' 52.2" +/- 0.3", SURF-LINE(6563) = 7+/-4 E-15 PLATE-ID=00H6 W-LINE(6563) = 0.17 +/- 0.03 5864( 0) - 07/18/95 18:21 - [ 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 PK81-14D1 WFPC2 IMAGE PC1 F588N CR-SPLIT=NO 1 150S ------------------------------------------------------------------------------------------------------------------------------------ 2 PK81-14D1 WFPC2 IMAGE PC1 F588N CR-SPLIT=NO 1 150S ------------------------------------------------------------------------------------------------------------------------------------ 3 PK81-14D1 WFPC2 IMAGE PC1 F588N CR-SPLIT=NO 1 500S ------------------------------------------------------------------------------------------------------------------------------------ 4 PK81-14D1 WFPC2 IMAGE PC1 F588N CR-SPLIT=NO 1 500S ------------------------------------------------------------------------------------------------------------------------------------ 5 PK81-14D1 WFPC2 IMAGE PC1 F588N CR-SPLIT=NO 1 500S END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 6 PK81-14D1 WFPC2 IMAGE PC1 F469N CR-SPLIT=NO 1 300S ------------------------------------------------------------------------------------------------------------------------------------ 7 PK81-14D1 WFPC2 IMAGE PC1 F469N CR-SPLIT=NO 1 300S ------------------------------------------------------------------------------------------------------------------------------------ 8 PK81-14D1 WFPC2 IMAGE PC1 F469N CR-SPLIT=NO 1 900S ------------------------------------------------------------------------------------------------------------------------------------ 9 PK81-14D1 WFPC2 IMAGE PC1 F469N CR-SPLIT=NO 1 700S END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 10 PK81-14D1 WFPC2 IMAGE PC1 F469N CR-SPLIT=NO 1 800S ------------------------------------------------------------------------------------------------------------------------------------ 11 PK81-14D1 WFPC2 IMAGE PC1 F469N CR-SPLIT=NO 1 700S ------------------------------------------------------------------------------------------------------------------------------------ 12 PK81-14D1 WFPC2 IMAGE PC1 F502N CR-SPLIT=NO 1 800S END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 13 PK81-14D1 WFPC2 IMAGE PC1 F502N CR-SPLIT=NO 1 300S ------------------------------------------------------------------------------------------------------------------------------------ 14 PK81-14D1 WFPC2 IMAGE PC1 F502N CR-SPLIT=NO 1 300S ------------------------------------------------------------------------------------------------------------------------------------ 15 PK81-14D1 WFPC2 IMAGE PC1 F502N CR-SPLIT=NO 1 900S ------------------------------------------------------------------------------------------------------------------------------------ 16 PK81-14D1 WFPC2 IMAGE PC1 F502N CR-SPLIT=NO 1 700S END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 5864( 0) - 07/18/95 18:21 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 PK81-14D1- HRS ACQ 2.0 MIRROR-N1 1 7.2S ONBOARD ACQ FOR 2 CENTRAL- STAR Comments: STEP-TIME=0.8S, EXPECT 1000 COUNTS IN STEP- TIME ------------------------------------------------------------------------------------------------------------------------------------ 2 PK81-14D1- HRS ACCUM 2.0 G140M 1241 FP-SPLIT=STD 1 1305.6S END ORBIT CENTRAL- STAR ------------------------------------------------------------------------------------------------------------------------------------ 5864( 0) - 07/18/95 18:21 - [ 7] Visit: 03 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 IRAS15154- WFPC2 IMAGE PC1 F656N CR-SPLIT=NO 1 1100S 5258 ------------------------------------------------------------------------------------------------------------------------------------ 2 IRAS15154- WFPC2 IMAGE PC1 F656N CR-SPLIT=NO 1 1200S END ORBIT 5258 ------------------------------------------------------------------------------------------------------------------------------------ 3 IRAS15154- WFPC2 IMAGE PC1 F656N CR-SPLIT=NO 1 1200S 5258 ------------------------------------------------------------------------------------------------------------------------------------ 4 IRAS15154- WFPC2 IMAGE PC1 F656N CR-SPLIT=NO 1 1400S END ORBIT 5258 ------------------------------------------------------------------------------------------------------------------------------------ 5864( 0) - 07/18/95 18:21 - [ 8] Summary Form for Proposal 5864 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Interstellar Medium ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements END ORBIT ONBOARD ACQ FOR 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F588N F469N F502N MIRROR-N1 G140M F656N ------------------------------------------------------------------------------------------------------------------------------------ Target Names PK81-14D1 PK81-14D1-CENTRAL-STAR IRAS15154-5258 ------------------------------------------------------------------------------------------------------------------------------------