Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4226c Report Date: 09-May-96:19:27 Version: ********** Check-in Date: ********** 1.Proposal Title: ULTRAVIOLET SPECTROSCOPY OF HYDROGEN-POOR PLANETARY NEBULAE ------------------------------------------------------------------------------------ 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 Harrington UNIVERSITY OF MARYLAND, DEPT USA 301-405-6266 ------------------------------------------------------------------------------------ 7. Abstract Planetary nebulae (PNe) form in the final stages of evolution of intermediate- and low-mass stars, and show abundances consistent with contamination by modest amounts of processed material. There is however 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. We propose to study 5 of the 6 currently known H-poor PNe with HST. The best studied object, Abell 30, shows that the majority of the emission line radiation is in the UV, and thus UV spectrophotometry is indispensable for quantitative analysis. Our proposed HST observations (in conjunction with our ground based work) will provide fundamental information (1) on helium-burning nucleosynthesis, by determining the ionic concentrations of H and He burning products; (2) on the physics of very dusty gas, by determining the energy balance; this is crucial since it now appears that due to the high dust-to-gas ratio, the energy input may be partially, and in some cases, primarily, due to photoelectric ejection by grains rather than by photoionization; and (3) on the interaction of the several thousand km/sec stellar winds with the nearby clumps of nebular material, by analysis of the velocity structure of the C IV 1550 line. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 9.75 par: 0 10. Num targs pri: 5 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS FOS FOC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4226c PI: Patrick Harrington Proposal Title: ULTRAVIOLET SPECTROSCOPY OF HYDROGEN-POOR PLANETARY NEBULAE ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Patrick Harrington UNIVERSITY OF MARYLAND, DEPT. OF USA ASTRONOMY, COLLEGE PARK Kazimierz J Borkowski UNIVERSITY OF MARYLAND, DEPT. OF USA ASTRONOMY, COLLEGE PARK Robin E Clegg ROYAL GREENWICH OBSERVATORY, UK X CAMBRIDGE Zlatan Tsvetanov JOHNS HOPKINS U., DEPT. PHYSICS USA AND ASTRONOMY, BALTIMORE ------------------------------------------------------------------------------------ 2. Scientific Justification. Page 3 ------------------------------------------------------------------------------------ 3. Description of proposed observations. We plan to use the FOC to image the hydrogen-poor gas in the two brightest and largest nebulae, A30 and A78. The primary goal is to obtain images in the UV, dominated by the C IV 1550 resonance line. In order to reduce the background, particularly a strong contribution from the geocoronal L-ALPHA emission, we plan to use the F152M filter. The chosen field of view is 22 arcsec squared in the FOC/96 configuration. UV images will be used later in the program to refine positions for spectroscopic work and to ease the aquisition of spectroscopic targets. We also plan to take O III images in the optical to obtain a comparable spatial resolution in this wavelength range. A comparison of optical and UV images should be interesting in view of differences in optical and UV spectra mentioned previously. The optical spectra of the two brightest emission knots in A30 (knots 3 and 4, Jacoby & Ford 1983) differ significantly. We chose these knots, as well as the bright central knot of emission in A78, for UV spectroscopy with the FOS and the blue digicon. We plan to obtain UV spectra with the large 4''.3 aperture in the high-resolution mode in order to obtain a good S/N ratio and not to degrade spectral resolution excessively due to the finite extent of the knots. We would like to reserve a choice as to the final combination of apertures and gratings upon examination of UV images. For example, bright, point- like knots of UV emission could be observed more efficiently in the lower resolution mode of the FOS. We plan to take high-resolution spectra with the GHRS to investigate broad C IV 1548, 1551 lines. We will obtain a spectrum of knot 3 in A30 centered on the CIV emission lines, in the medium-resolution mode of the GHRS and through the LSA. These lines (several independent components) are also seen in absorption in the central star of A78 - we will take a spectrum of the central star through the SSA to obtain a high quality data on these features. Positions of spectroscopic apertures in the fainter Galactic nebulae, the M22 PN and IRAS 15154-5258, were chosen on the basis of high-resolution O III images taken with the New Technology Telescope in La Silla. In both cases bright knots of emission can be seen in the east. We will take far-UV, low-resolution (G160L) FOS spectra of these knots, with the one arcsec aperture in the M22 nebula, and with the 4''.3 aperture in IRAS 15154-5258. An investigation of the stellar wind from the central star of the M22 PN, predicted theoretically to be dynamically important in the interaction of this nebula with the ISM, will be pursued by taking a high-resolution, far-UV FOS spectrum of the star through the large 4''.3 aperture. Finally, imaging in the optical and UV spectroscopy of a small, 3''.2 diameter PN in the Large Magellanic Cloud will be performed. Again, we chose the high-resolution mode of the FOS with the 4''.3 aperture for the same reasons as in A30 and A78. And again, we would like to make a final choice of apertures and gratings and of the exact position upon examination of an HST image. Page 4 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The thrust of our efforts is concentrated in the UV, and requires space observations. A30, A78, and the M22 PN were extensively studied by the IUE satellite. Multi-hour exposures of A30 (Harrington & Feibelman 1984; Harrington 1986), A78 (Kaler, Feibelman, & Henrichs 1988), and M22 (Cohen & Gillett 1989) pushed the IUE to the limits and provided us with basic information about UV properties of these objects. This information is the basis for the current proposal. Further progress can now be made only with the HST, with its superior spatial resolution and with the much larger gathering power. The two recently discovered hydrogen-poor PNe, LMC 26 and IRAS 15154-5258, can be studied only with the HST because of their relative faintness. Note that our proposal concentrates on UV spectroscopy which suffered relatively little from problems connected with the spherical aberration of the primary mirror. We have started a ground-based observational program to support this project. The high-resolution, continuum subtracted O III images of the M22 PN and IRAS 15154-5258 have been already used to locate bright emission knots to be observed by the HST. We have also obtained spectroscopic data for IRAS 15154-5258, confirming high (T > 20,000 K) electron temperature and refining the interstellar reddening. We used these data to estimate the exposure time for this object. Further observational and theoretical work in support of this project is in progress. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. We would like to obtain images with the FOC at least several weeks before spectroscopic observations of A30, A78, and the LMC PN. This would help us with the target aquisition and would be useful in refining positions, apertures, and filters for spectroscopic work. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. We expect to reduce the FOC images and the FOS and GHRS spectra at the University of Maryland. We have an extensive network of Sun workstations and a number of faculty with HST time, so that there should be ample local expertise in the handling of HST data. We have already obtained ground-based optical data for several of our targets, including filter images, spectra of the nebulae, and spectra of the central stars. We will continue to pursue this support work. The analysis will involve use of the photoionization modeling codes developed by J. P. Harrington for planetary nebulae, and modified in collaboration with K. Borkowski to include heating by ejection of grain photoelectrons. We have already used this code to investigate the nebular emission from the M22 object (Borkowski & Harrington 1991). The basic idea is to obtain the mass of dust and its optical depth from the far-IR (IRAS) emission, and then construct models of the photoionized gas including the heat input from the dust. UV observations of the M22 nebula with HST will establish the energy loss rate from the gas and immediately put constraints of the physics of the grain photoemission process. We will attempt to apply the same procedure to the other hydrogen-poor PNe. If we succeed in matching the UV and optical data for other objects, as well as the thermal IR fluxes, we can then feel secure in the ionization correction factors and the dust-to-gas ratio for these important objects. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. ------------------------------------------------------------------------------------ 9. Description of previous HST work. 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. Page 5 ------------------------------------------------------------------------------------ 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 II's, as well as a Multiflow mini-super computer. This network and supporting technical staff provides an excellent environment for data reduction and modeling. ------------------------------------------------------------------------------------ 11. Address Information Name: PATRICK HARRINGTON Category: PI Institution: UNIVERSITY OF MARYLAND, DEPT. OF Address: City: COLLEGE PARK State: MD Zip Code: 20742 Country: USA Telephone: (301) 405-1517 Telex (or e-mail): 710-826-0352 ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4226c [ 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| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 PK208+33D1 G,502,A,184 PLATE-ID=03DI, 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) = 9 +/- 2 E-14 DEC = +17D 52' 45.7" +/- 4 SURF-LINE(1550) = 30 +/- 5 E-15 0.3" 5 W-LINE(5007) = 0.17 +/- 0.03 6 W-LINE(1550) = 1.6 +/- 0.2 7 SIZE = 0.2 SIZE = 0.5 Comments: FLUXVAL_1 REFERS TO CENTRAL STAR. LINE INFORMATION FOR EMISSION KNOTS ------------------------------------------------------------------------------------------------------------------------------------ 2 PK208+33D1- A,184 PLATE-ID=03DI, 2000 V = +10 1 V=14.30+/-0.01, TYPE=OVI OFFSET RA = 8H 46M 53.46S +/- 2 B-V=-0.07+/-0.01 ABELL30- 0.02S, 3 E(B-V)=0.30+/-0.03 CENTRAL-STAR DEC = +17D 52' 45.7" +/- -OFFSET 0.3" GSC1396-1621 -OFFSET ------------------------------------------------------------------------------------------------------------------------------------ 3 PK208+33D1- G,502,927 R = 6.61", 2000 1 SURF-LINE(5007) = 10 +/- 2 E-14 KNOT3 PA = 329.7D, 2 SURF-LINE(1550) = 20 +/- 3 E-15 ABELL30- FROM 2 3 W-LINE(1550) = 1.6 +/- 0.2 KNOT3 4 W-LINE(5007) = 0.17 +/- 0.03 5 SURF-LINE(1909) = 30 +/- 4 E-16 6 W-LINE(1909) = 1.0 +/- 0.2 ------------------------------------------------------------------------------------------------------------------------------------ 4 PK208+33D1- G,502,927 R = 3.53", 2000 1 SURF-LINE(5007) = 8 +/- 2 E-14 KNOT4 PA = 221.7D, 2 SURF-LINE(1550) = 16 +/- 3 E-15 ABELL30- FROM 2 3 W-LINE(1550) = 1.6 +/- 0.2 KNOT4 4 W-LINE(5007) = 0.17 +/- 0.03 5 SURF-LINE(1909) = 20 +/- 3 E-16 6 W-LINE(1909) = 1.0 +/- 0.2 7 SURF-LINE(2423) = 25 +/- 4 E-15 8 W-LINE(2423) = 0.17 +/- 0.03 ------------------------------------------------------------------------------------------------------------------------------------ 5 PK81-14D1 G,502,A,184 PLATE-ID = 0054, 2000 V = +17 1 V=13.25+/- ABELL78 RA = 21H 35M 29.39S +/- 2 0.01,TYPE=OVI,A(V)=0.46+/-0.10 GSC2704-1582 0.02S, 3 SURF-LINE(5007) = 4 +/- 1 E-14 DEC = +31D 41' 46.0" +/- 4 SURF-LINE(1550) = 14 +/- 4 E-15 0.3" 5 W-LINE(5007) = 0.17 +/- 0.03 6 W-LINE(1550) = 1.6 +/- 0.2 7 SIZE = 0.2 SIZE = 0.5 Comments: FLUXVAL_1 REFERS TO CENTRAL STAR. FLUXVAL_2 FOR BRIGHTEST KNOTS. ------------------------------------------------------------------------------------------------------------------------------------ 6 PK81-14D1- A,184 PLATE-ID = 0054, 2000 V = +17 1 V=13.25+/-0.01,TYPE=OVI CENTRAL-STAR RA = 21H 35M 29.39S +/- 2 B-V=-0.21+/-0.01 ABELL78- 0.02S, 3 E(B-V)=0.15+/-0.03 CENTRAL-STAR DEC = +31D 41' 46.0" +/- 4 F-CONT(1550) = 12 +/- 1 E-13 GSC2704-1582 0.3" ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4226c [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 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| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 7 PK81-14D1- G,502,927 R = 3.01", 2000 1 SURF-LINE(1550) = 14 +/- 4 E-15 KNOT ABELL78 PA = 134.5D, 2 W-LINE(1550) = 1.6 +/- 0.2 -KNOT FROM 6 3 SURF-LINE(1909) = 18 +/- 4 E-16 4 W-LINE(1909) = 1.0 +/- 0.2 5 SURF-LINE(2423) = 20 +/- 4 E-15 6 W-LINE(2423) = 0.17 +/- 0.03 ------------------------------------------------------------------------------------------------------------------------------------ 8 IRAS1833- A,184,C,201 RA = 18H 36M 22.78S +/- 2000 V = -153 COMP 1 V=14.3+/-0.2,TYPE=O 2357-CENTRAL 0.02S, 2 B-V=0.5+/-0.1 -STAR DEC = -23D 55' 19.26" +/- 3 E(B-V)=0.5+/-0.05 0.3" 4 F-CONT(1550) = 45 +/- 10 E-15 Comments: COMPANION RED STAR 1" TO NORTH ------------------------------------------------------------------------------------------------------------------------------------ 9 IRAS1833- G,502,927,C,201 R = 2.3", 2000 V = -153 1 SURF-LINE(1550) = 80 +/- 20 E-17 2357-KNOT PA = 77D, 2 W-LINE(1550) = 0.17 +/- 0.03 FROM 8 Comments: EXPECTED FLUX. ------------------------------------------------------------------------------------------------------------------------------------ 10 IRAS15154- A RA = 15H 19M 8.19S +/- 1.0", J2000 1 V=16.2+/-0.2 5258-OFFSET DEC = -53D 9' 47.1" +/- 1.0" ------------------------------------------------------------------------------------------------------------------------------------ 11 IRAS15154- G,502,927 RA-OFF = +0.848S +/- 0.022S, 2000 1 SURF-LINE(1550) = 60 +/- 15 E-17 5258-KNOT DEC-OFF = -5.5" +/- 0.2", 2 W-LINE(1550) = 0.17 +/- 0.03 FROM 10 Comments: EXPECTED FLUXES. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4226c [ 8] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1.3 PK208+33D1- FOS/BL ACQ/ 4.3 MIRROR 1 2.3S 17 1 1 CYCLE 2 OFFSET BINARY 2 ONBOARD ACQ FOR 3 1.31-1.43 GROUP 1.30 - 1.43 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 1.31 PK208+33D1- FOS/BL ACCUM 1.0 G130H 1 40M 30 2 1 CYCLE 2 KNOT3 3 GROUP 1.30 - 1.43 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 1.32 PK208+33D1- FOS/RD ACCUM 1.0 G190H 1 30M 15 5 1 CYCLE 2 KNOT3 6 GROUP 1.30 - 1.43 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 1.33 PK208+33D1- FOS/RD ACCUM 1.0 G270H 1 30M 15 5 1 CYCLE 2 KNOT3 6 GROUP 1.30 - 1.43 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 1.41 PK208+33D1- FOS/BL ACCUM 1.0 G130H 1 2193S 30 2 1 CYCLE 2 KNOT4 3 GROUP 1.30 - 1.43 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 1.42 PK208+33D1- FOS/RD ACCUM 1.0 G190H 1 30M 15 5 1 CYCLE 2 KNOT4 6 GROUP 1.30 - 1.43 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 1.43 PK208+33D1- FOS/RD ACCUM 1.0 G270H 1 30M 15 7 2 CYCLE 2 KNOT4 8 GROUP 1.30 - 1.43 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 1.5 PK208+33D1- HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 1.8S 10 1 2 CYCLE 2 OFFSET 2 ONBOARD ACQ FOR 3 1.6 ------------------------------------------------------------------------------------------------------------------------------------ 1.6 PK208+33D1- HRS ACCUM 2.0 G160M 1550 1 30M 7 7 2 CYCLE 2 KNOT4 8 ------------------------------------------------------------------------------------------------------------------------------------ 2.03 PK81-14D1- FOS/BL ACQ/ 4.3 MIRROR BRIGHT=78000 1 0.66S 30 1 1 CYCLE 2 CENTRAL- BINARY FAINT=1550 2 ONBOARD ACQ FOR STAR 3 2.1-2.3 GROUP 2.03 - 2.3 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 2.1 PK81-14D1- FOS/BL ACCUM 1.0 G130H 1 40M 30 1 1 CYCLE 2 KNOT 2 GROUP 2.03 - 2.3 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 2.2 PK81-14D1- FOS/RD ACCUM 1.0 G190H 1 30M 15 2 1 CYCLE 2 KNOT 3 GROUP 2.03 - 2.3 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4226c [ 9] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 2.3 PK81-14D1- FOS/RD ACCUM 1.0 G270H 1 30M 15 5 2 CYCLE 2 KNOT 6 GROUP 2.03 - 2.3 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 2.4 PK81-14D1- HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 1.8S 10 1 2 CYCLE 2 CENTRAL- 2 ONBOARD ACQ FOR STAR 3 2.41 ------------------------------------------------------------------------------------------------------------------------------------ 2.41 PK81-14D1- HRS ACCUM 0.25 G160M 1540 1 30M 15 3 2 CYCLE 2 CENTRAL- STAR ------------------------------------------------------------------------------------------------------------------------------------ 3 IRAS1833- FOS/BL ACQ/ 4.3 MIRROR 1 2.8S 17 1 1 CYCLE 2 2357- BINARY 2 ONBOARD ACQ FOR CENTRAL- 3 3.1-3.2 Comments: CLOSE COMPANION 1" TO NORTH. ------------------------------------------------------------------------------------------------------------------------------------ 3.1 IRAS1833- FOS/BL ACCUM 4.3 G130H 1 40M 17 4 2 CYCLE 2 2357- CENTRAL- ------------------------------------------------------------------------------------------------------------------------------------ 3.2 IRAS1833- FOS/BL ACCUM 1.0 G160L 1 30M 5 1 1 CYCLE 2 2357-KNOT 2 ------------------------------------------------------------------------------------------------------------------------------------ 4 IRAS15154- FOS/BL ACQ/ 4.3 MIRROR 1 120S 17 1 1 CYCLE 2 5258-OFFSET BINARY ONBOARD ACQ FOR 4.1 ------------------------------------------------------------------------------------------------------------------------------------ 4.1 IRAS15154- FOS/BL ACCUM 4.3 G160L 1 55M 4 1 1 CYCLE 2 5258-KNOT 2 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4226c [ 10] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL FOS/RD HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/BINARY ACCUM ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN BRIGHT=78000 FAINT=1550 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 9.75 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category PLANETARY NEBULAE ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 2; ONBOARD ACQ FOR 1.31-1.43; GROUP 1.30 - 1.43 NO GAP ONBOARD ACQ FOR 1.6 ONBOARD ACQ FOR 2.1-2.3; GROUP 2.03 - 2.3 NO GAP ONBOARD ACQ FOR 2.41 CYCLE 2 ONBOARD ACQ FOR 3.1-3.2 ONBOARD ACQ FOR 4.1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G130H G190H G270H MIRROR-N2 G160M G160L ------------------------------------------------------------------------------------------------------------------------------------ Target Names PK208+33D1 ABELL30 GSC1396-1621 PK208+33D1-OFFSET ABELL30-CENTRAL-STAR-OFFSET GSC1396-1621-OFFSET PK208+33D1-KNOT3 ABELL30-KNOT3 PK208+33D1-KNOT4 ABELL30-KNOT4 PK81-14D1 ABELL78 GSC2704-1582 PK81-14D1-CENTRAL-STAR ABELL78-CENTRAL-STAR PK81-14D1-KNOT ABELL78-KNOT IRAS1833-2357-CENTRAL-STAR IRAS1833-2357-KNOT IRAS15154-5258-OFFSET IRAS15154-5258-KNOT ------------------------------------------------------------------------------------------------------------------------------------