6413( 7) - 03/28/96 13:17 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6413 Version: 7 Check-in Date: 28-Mar-1996 13:11:42 1.Proposal Title: High Velocity Thermal Shock Instabilities in the Vela Supernova Remnant ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle INTERSTELLAR MEDIUM GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Kenneth Sembach Massachusetts Institute of Technology CoI: John Raymond Harvard Smithsonian Center for N Astrophysics CoI: Edward Jenkins Princeton University Observatory N CoI: Anthony Danks Hughes STX / Goddard Space Flight Center N ------------------------------------------------------------------------------------ 6. Abstract Supernovae dominate the ionization, heating, and mass motions of interstellar gas in the Milky Way, yet detailed descriptions of these processes remain elusive because observational information about interstellar shocks is limited. We propose to use the GHRS to study the properties of high velocity gas in the Vela supernova remnant through ultraviolet absorption line spectroscopy. This approach to studying the neutral and ionized gases in SNRs provides detailed physical condition and profile shape information along infinitesimal beams at high spectral resolution. We will 1) Study the observational signatures of thermal instabilities created by a loss of pressure equilibrium as the high velocity shock-accelerated gas cools. These catastrophic thermal instabilities affect the morphologies and diagnostic line ratios of interstellar shocks and must be understood to interpret the physical conditions and processes occurring in shocked interstellar environments. 2) Compare the velocity offsets, strengths, and profile shapes of the high velocity absorption features to improve models of shock ionization and remnant-ISM interactions. 3) Determine the local physical conditions that give rise to gas-phase abundance variations at different velocities and places within the remnant. The four sight lines to be studied have a rich velocity structure that will allow us to explore a range of shock conditions and remnant environments. ------------------------------------------------------------------------------------ 6413( 7) - 03/28/96 13:17 - [ 2] Observations Description ------------------------ We will use the intermediate-resolution gratings G140M, G160M, G200M, and G270M to obtain absorption line measurements of ultraviolet species in the high velocity (V > 140 km/sec) gas toward HD 72997 and HD 74194. The resolution of the data will be better than 15 km/sec and the S/N ratios will be greater than 70:1. We will use the Ech-A and Ech-B gratings to provide high-resolution (FWHM = 3.5 km/sec) measurments of the high velocity gas lines toward HD 74455 and HD 75821. The S/N levels will be in excess of 70:1 for most observations. The LSA will be used for all observations to maximize throughput. FP-Split = 4 will be used for most observations, although FP-Split=2 is used in a few cases to reduce the number of HRS words per visit to make schedulability easier. Also, the normal acquisition mirrors can be used since these objects, even though bright, should not "saturate" the detectors if a small step stime (0.2-0.4 sec) is used. Fluxes are taken from recent IUE spectra. Real Time Justification ----------------------- No special scheduling requirements are necessary. Calibration Justification ------------------------- No special calibration requirements are necessary. Additional Comments ------------------- No additional comments at this time. ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6413( 7) - 03/28/96 13:17 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD72997 STAR, B0-B2 III-I RA = 08H 34M 8.11S +/- 0.05S, J2000 V = 7.46 DEC = -44D 32' 41.57" +/- 0.01" B-V = -0.18 Comments: Coordinates and proper motions from Hipparcos. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 -0.0026 0.005 0.0 2 HD74194 STAR, Supergiant O RA = 08H 40M 47.79S +/- 0.01S, J2000 V = -4 V = 7.57 DEC = -45D 03' 30.25" +/- 0.01" B-V = -0.20 Comments: Coordinates and proper motions from Hipparcos. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 -0.0006 0.001 0.0 3 HD74455 STAR, B0-B2 V-IV RA = 08H 42M 16.19S +/- 0.01S, J2000 V = +58 V = 5.50 DEC = -48D 05' 57.3" +/- 0.1" B-V = -0.17 Comments: Coordinates and proper motions from Hipparcos. Star is brighter member of binary system (sep = 0.3"). Companion is 1.3 magnitudes fainter (V = 6.80). Spectral type of companion is unknown, but probably later. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 -0.0011 -0.009 0.0 4 HD75821 STAR, B0-B2 III-I RA = 08H 50M 33.46S +/- 0.02S, J2000 V = +8 V = 5.10 DEC = -46D 31' 45.4" +/- 0.2" B-V = -0.21 Comments: Coordinates and proper motions from Hipparcos. Star is brighter member of binary system (sep = 3.2"). Companion is 4.1 magnitudes fainter (V = 9.2). Note that is consistent with previous HST observations of star. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 -0.00068 -0.005 0.0 6413( 7) - 03/28/96 13:17 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: HD 72997 observations. Use G140M, G160M, G200M, G270M. Number exposures beginning with 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD72997 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,S 1 1.8S ONBOARD ACQ FOR 2-15 EARCH-SIZE=3 Comments: STEP-TIME=0.2 seconds. Expect about 90,000 cnt/sec per step for mirror N2. Using A2 increases the overhead dramatically. We should be okay for BRIGHT=RETURN. ------------------------------------------------------------------------------------------------------------------------------------ 2 HD72997 HRS ACCUM 2.0 G160M 1539.2 FP- 1 326.4S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get C IV, Si II ------------------------------------------------------------------------------------------------------------------------------------ 3 HD72997 HRS ACCUM 2.0 G160M 1552.0 FP- 1 435.2S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get C IV, C I ------------------------------------------------------------------------------------------------------------------------------------ 4 HD72997 HRS ACCUM 2.0 G160M 1664.5 FP- 1 326.4S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Al II, C I ------------------------------------------------------------------------------------------------------------------------------------ 5 HD72997 HRS ACCUM 2.0 G160M 1817.6 FP- 1 544.0S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Si II, S I ------------------------------------------------------------------------------------------------------------------------------------ 6 HD72997 HRS ACCUM 2.0 G200M 1860.0 FP- 1 435.2S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Al III ------------------------------------------------------------------------------------------------------------------------------------ 7 HD72997 HRS ACCUM 2.0 G200M 2060.0 FP- 1 544.0S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Zn II, Cr II ------------------------------------------------------------------------------------------------------------------------------------ 6413( 7) - 03/28/96 13:17 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 8 HD72997 HRS ACCUM 2.0 G270M 2374.0 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Fe II (2367, 2374, 2382) ------------------------------------------------------------------------------------------------------------------------------------ 9 HD72997 HRS ACCUM 2.0 G270M 2593.0 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Fe II, Mn II ------------------------------------------------------------------------------------------------------------------------------------ 10 HD72997 HRS ACCUM 2.0 G270M 2800.0 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Mg II ------------------------------------------------------------------------------------------------------------------------------------ 11 HD72997 HRS ACCUM 2.0 G270M 2850.0 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Mg I ------------------------------------------------------------------------------------------------------------------------------------ 12 HD72997 HRS ACCUM 2.0 G140M 1245.6 FP- 1 652.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get N V, Mg II, S II, Ge II, Kr I ------------------------------------------------------------------------------------------------------------------------------------ 13 HD72997 HRS ACCUM 2.0 G140M 1299.3 FP- 1 435.2S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get O I, Si II, Si II*, (Si III- stellar) ------------------------------------------------------------------------------------------------------------------------------------ 14 HD72997 HRS ACCUM 2.0 G140M 1327.0 FP- 1 326.4S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get C II, C II*, C I, Ni II ------------------------------------------------------------------------------------------------------------------------------------ 15 HD72997 HRS ACCUM 2.0 G140M 1396.0 FP- 1 652.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Si IV ------------------------------------------------------------------------------------------------------------------------------------ 6413( 7) - 03/28/96 13:17 - [ 6] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: HD 74194 observations. Use G140M, G160M, G270M. Number exposures beginning with 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD74194 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,S 1 1.8S ONBOARD ACQ FOR 2-10 EARCH-SIZE=3 Comments: STEP-TIME=0.2 seconds. ------------------------------------------------------------------------------------------------------------------------------------ 2 HD74194 HRS ACCUM 2.0 G160M 1817.6 FP- 1 870.4S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Si II, S I ------------------------------------------------------------------------------------------------------------------------------------ 3 HD74194 HRS ACCUM 2.0 G270M 2374.0 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Fe II (2367, 2374, 2382) ------------------------------------------------------------------------------------------------------------------------------------ 4 HD74194 HRS ACCUM 2.0 G270M 2800.0 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Mg II ------------------------------------------------------------------------------------------------------------------------------------ 5 HD74194 HRS ACCUM 2.0 G270M 2850.0 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Mg I ------------------------------------------------------------------------------------------------------------------------------------ 6 HD74194 HRS ACCUM 2.0 G140M 1249.6 FP- 1 1305.6S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get N V, Mg II, S II, Si II, C I? ------------------------------------------------------------------------------------------------------------------------------------ 7 HD74194 HRS ACCUM 2.0 G140M 1299.3 FP- 1 435.2S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get O I, Si II, Si II*, (Si III- stellar) ------------------------------------------------------------------------------------------------------------------------------------ 6413( 7) - 03/28/96 13:17 - [ 7] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 8 HD74194 HRS ACCUM 2.0 G140M 1327.0 FP- 1 435.2S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get C II, C II*, C I, Ni II ------------------------------------------------------------------------------------------------------------------------------------ 9 HD74194 HRS ACCUM 2.0 G140M 1396.0 FP- 1 544.0S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Si IV ------------------------------------------------------------------------------------------------------------------------------------ 10 HD74194 HRS ACCUM 2.0 G140M 1552.7 FP- 1 1740.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get C IV, C I ------------------------------------------------------------------------------------------------------------------------------------ 6413( 7) - 03/28/96 13:17 - [ 8] Visit: 03 Visit Requirements: On Hold Comments: Additional Comments: HD 74455 observations. Use Ech-A, Ech-B. Number exposures beginning with 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD74455 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,S 1 1.8S ONBOARD ACQ FOR 2-17 EARCH-SIZE=3 Comments: STEP-TIME=0.2 seconds. Expect about 61,000 cnt/sec per step. Okay for BRIGHT=RETURN. *Note*: If MIRROR-A1 is used instead, expect only about 675 counts/sec for STEP-TIME=1.0 ------------------------------------------------------------------------------------------------------------------------------------ 2 HD74455 HRS ACCUM 2.0 ECH-A 1206.0 FP- 1 544.0S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Si III (S/N = 72) ------------------------------------------------------------------------------------------------------------------------------------ 3 HD74455 HRS ACCUM 2.0 ECH-A 1239.9 FP- 1 326.4S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get N V, Mg II (S/N = 108) ------------------------------------------------------------------------------------------------------------------------------------ 4 HD74455 HRS ACCUM 2.0 ECH-A 1252.2 FP- 1 163.2S SPLIT=TWO,COMB= FOUR,STEP- PATT=DEF Comments: Exposure to get S II (S/N = 80) ------------------------------------------------------------------------------------------------------------------------------------ 5 HD74455 HRS ACCUM 2.0 ECH-A 1303.0 FP- 1 163.2S SPLIT=TWO,COMB= FOUR,STEP- PATT=DEF Comments: Exposure to get O I, Si II (S/N = 82) ------------------------------------------------------------------------------------------------------------------------------------ 6 HD74455 HRS ACCUM 2.0 ECH-A 1329.2 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get C I (S/N = 67) ------------------------------------------------------------------------------------------------------------------------------------ 7 HD74455 HRS ACCUM 2.0 ECH-A 1335.1 FP- 1 163.2S SPLIT=TWO,COMB= FOUR,STEP- PATT=DEF Comments: Exposure to get C II, C II* (S/N = 83) ------------------------------------------------------------------------------------------------------------------------------------ 6413( 7) - 03/28/96 13:17 - [ 9] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 8 HD74455 HRS ACCUM 2.0 ECH-A 1393.0 FP- 1 761.6S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Si IV (S/N = 72) ------------------------------------------------------------------------------------------------------------------------------------ 9 HD74455 HRS ACCUM 2.0 ECH-A 1550.0 FP- 1 979.2S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get C IV (S/N = 62) ------------------------------------------------------------------------------------------------------------------------------------ 10 HD74455 HRS ACCUM 2.0 ECH-A 1670.7 FP- 1 489.6S SPLIT=TWO,COMB= FOUR,STEP- PATT=DEF Comments: Exposure to get Al II (S/N = 56) ------------------------------------------------------------------------------------------------------------------------------------ 11 HD74455 HRS ACCUM 2.0 ECH-B 1807.0 FP- 1 435.2S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Si II, S I (S/N = 79) ------------------------------------------------------------------------------------------------------------------------------------ 12 HD74455 HRS ACCUM 2.0 ECH-B 1854.5 FP- 1 544.0S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Al III (S/N = 76) ------------------------------------------------------------------------------------------------------------------------------------ 13 HD74455 HRS ACCUM 2.0 ECH-B 2061.2 FP- 1 326.4S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Zn II, Cr II (S/N = 97) ------------------------------------------------------------------------------------------------------------------------------------ 14 HD74455 HRS ACCUM 2.0 ECH-B 2370.0 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Fe II (S/N = 75) ------------------------------------------------------------------------------------------------------------------------------------ 15 HD74455 HRS ACCUM 2.0 ECH-B 2597.3 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get Fe II, Mn II (S/N = 72) ------------------------------------------------------------------------------------------------------------------------------------ 6413( 7) - 03/28/96 13:17 - [ 10] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 16 HD74455 HRS ACCUM 2.0 ECH-B 2799.9 FP- 1 108.8S SPLIT=TWO,COMB= FOUR,STEP- PATT=DEF Comments: Exposure to get Mg II (S/N = 90) ------------------------------------------------------------------------------------------------------------------------------------ 17 HD74455 HRS ACCUM 2.0 ECH-B 2852.9 FP- 1 108.8S SPLIT=TWO,COMB= FOUR,STEP- PATT=DEF Comments: Exposure to get Mg I (S/N = 72) ------------------------------------------------------------------------------------------------------------------------------------ 6413( 7) - 03/28/96 13:17 - [ 11] Visit: 04 Visit Requirements: On Hold Comments: Additional Comments: HD 75821 observations. Use Ech-A. Number exposures beginning with 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD75821 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,S 1 1.8S ONBOARD ACQ FOR 2-6 EARCH-SIZE=3 Comments: STEP-TIME=0.2 seconds. Expect about 51,000 cnt/sec per step. Okay for BRIGHT=RETURN. *Note*: If MIRROR-A1 is used instead, expect only about 575 counts/sec for STEP-TIME=1.0 ------------------------------------------------------------------------------------------------------------------------------------ 2 HD75821 HRS ACCUM 2.0 ECH-A 1206.0 FP- 1 108.8S SPLIT=TWO,COMB= FOUR,STEP- PATT=DEF Comments: Exposure to get Si III (S/N = 82) ------------------------------------------------------------------------------------------------------------------------------------ 3 HD75821 HRS ACCUM 2.0 ECH-A 1239.9 FP- 1 108.8S SPLIT=FOUR,COMB =FOUR,STEP- PATT=DEF Comments: Exposure to get N V, Mg II (S/N = 82) ------------------------------------------------------------------------------------------------------------------------------------ 4 HD75821 HRS ACCUM 2.0 ECH-A 1393.0 FP- 1 435.2S SPLIT=TWO,COMB= FOUR,STEP- PATT=DEF Comments: Exposure to get Si IV (S/N = 70) ------------------------------------------------------------------------------------------------------------------------------------ 5 HD75821 HRS ACCUM 2.0 ECH-A 1550.0 FP- 1 598.4S SPLIT=TWO,COMB= FOUR,STEP- PATT=DEF Comments: Exposure to get C IV (S/N = 56) ------------------------------------------------------------------------------------------------------------------------------------ 6 HD75821 HRS ACCUM 2.0 ECH-A 1303.0 FP- 1 108.8S SPLIT=TWO,COMB= FOUR,STEP- PATT=DEF Comments: Exposure to get O I, Si II (S/N = 90) ------------------------------------------------------------------------------------------------------------------------------------ 6413( 7) - 03/28/96 13:17 - [ 12] Summary Form for Proposal 6413 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=3 STEP-PATT=DEF COMB=FOUR FP-SPLIT=FOUR FP-SPLIT=TWO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2-15 ONBOARD ACQ FOR 2-10 ONBOARD ACQ FOR 2-17 ONBOARD ACQ FOR 2-6 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G160M G200M G270M G140M MIRROR-N1 ECH-A ECH-B ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD72997 HD74194 HD74455 HD75821 ------------------------------------------------------------------------------------------------------------------------------------