7739( 6) - 02/06/98 13:22 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7739 Version: 6 Check-in Date: 06-Feb-1998 13:21:04 1.Proposal Title: Star Formation in the Prototype Super Star Cluster R136 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO/CAR 6 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Philip Massey National Optical Astronomy Observatories CoI: Deidre Hunter Lowell Observatory N ------------------------------------------------------------------------------------ 5. Abstract R136 is the prototype ``super star cluster'', the result of an intense star- formation event. Similarly extreme objects have now been recognized in more distant galaxies, and may in fact be the young analogs of globular clusters. Located in the LMC, R136 is the only such young, compact, luminous star cluster that can be studied in sufficent detail for a direct determination of its stellar content, and thus represents our best opportunity to examine the star formation process in such events. Therefore, we are proposing to obtain the optical spectra of roughly 100 of the most luminous stars in R136 necessary to accurately place them on an HR diagram and thus infer their masses and ages from evolutionary tracks. This will directly tell us the initial mass function of the massive stars in this extreme object, and provide the chronology of star formation within the cluster. The comparison with the IMF's determined for the same mass range in ``normal" OB associations and clusters, as well as field stars, will reveal whether the star formation process depends on the concentration of the star-forming region. The ages and age spread of the massive stars, when compared to the ages of intermediate mass stars on pre-main sequence tracks, will show how star formation proceeded within the region. ------------------------------------------------------------------------------------ 7739( 6) - 02/06/98 13:22 - [ 2] Observations Description ------------------------ We will use STIS/CCD to complete our program of observing individual stars in the R136 cluster. In these final 8 orbits will we aim for high SNR (100) per 2- pixel spectral resolution element in the blue (G430M) centered at 4451, plus a SNR of 50 at Halpha using the G750M grating centered at 6581, using stars found earlier by FOS to be of type O3. These new data will allow us to complete the science goals of the program by determining accurate effective temperatures for placement on the HRD. In order to achieve a SNR of 100 we were advised by Ron Downs to dither, using a PATTERN=ALONG-SLIT, NUM-POS=3, and a step size of 0.15". Because our stars are quite crowded, we are tweaking up in the 52x0.2" aperture using an isolated offset star, and observing the program stars by blind offset. We repeak the peak-up about half-way through the 8 orbits. We finish the visit by obtaining two exposures of faint stars with the G750L grating, aiming for a SNR of about 80. Real Time Justification ----------------------- We will utilize the fact that R136 is in a CVZ to significantly improve our observing throughput. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7739( 6) - 02/06/98 13:22 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 R136-OFFSET EXT-STAR, WOLF RAYET - RA=05H 38M 44.3478S +/- J2000 V = 13.30+/-0.06 WN 0.1S,DEC=-69D 6' 6.242" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; this is our offset star. 7 R136-007 EXT-CLUSTER, OPEN RA=05H 38M 40.3186S +/- J2000 V = 13.01+/-0.08 CLUSTER, EXT-STAR 0.1S,DEC=-69D 6' 0.172" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 18 R136-018 EXT-CLUSTER, OPEN RA=05H 38M 44.2211S +/- J2000 V = 13.91+/-0.07 CLUSTER, EXT-STAR 0.1S,DEC=-69D 5' 56.954" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 20 R136-020 EXT-CLUSTER, OPEN RA=05H 38M 42.5208S +/- J2000 V = 13.93+/-0.04 CLUSTER, EXT-STAR 0.1S,DEC=-69D 6' 3.112" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 24 R136-024 EXT-CLUSTER, OPEN RA=05H 38M 42.4992S +/- J2000 V = 14.06+/-0.06 CLUSTER, EXT-STAR 0.1S,DEC=-69D 6' 2.961" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 36 R136-036 EXT-CLUSTER, OPEN RA=05H 38M 42.7584S +/- J2000 V = 14.49+/-0.06 CLUSTER, EXT-STAR 0.1S,DEC=-69D 6' 3.214" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 40 R136-040 EXT-CLUSTER, OPEN RA=05H 38M 42.5555S +/- J2000 V = 14.60+/-0.03 CLUSTER, EXT-STAR 0.1S,DEC=-69D 6' 1.587" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 44 R136-044 EXT-CLUSTER, OPEN RA=05H 38M 41.9658S +/- J2000 V = 14.66+/-0.06 CLUSTER, EXT-STAR 0.1S,DEC=-69D 6' 14.745" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 47 R136-047 EXT-CLUSTER, OPEN RA=05H 38M 42.7331S +/- J2000 V = 14.75+/-0.04 CLUSTER, EXT-STAR 0.1S,DEC=-69D 6' 2.246" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 55 R136-055 EXT-CLUSTER, OPEN RA=05H 38M 42.5984S +/- J2000 V = 14.86+/-0.03 CLUSTER, EXT-STAR 0.1S,DEC=-69D 6' 4.977" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 7739( 6) - 02/06/98 13:22 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 115 R136-115 EXT-CLUSTER, OPEN RA=05H 38M 42.3422S +/- J2000 V = 15.83+/-0.06 CLUSTER, EXT-STAR 0.1S,DEC=-69D 6' 2.139" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 123 R136-123 EXT-CLUSTER, OPEN RA=05H 38M 42.1492S +/- J2000 V = 15.96+/-0.03 CLUSTER, EXT-STAR 0.1S,DEC=-69D 6' 4.915" +/- B-V = 0.0+/-0.2 0.5",PLATE-ID=06B0 E(B-V) = 0.38+/-0.05 Comments: Early-type Star in R136 cluster; Position wrt target 1 +/- 0.01" 7739( 6) - 02/06/98 13:22 - [ 5] Visit: 01 Visit Priority: Visit Requirements: CVZ 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 R136-OFFSET STIS/C ACQ F28X50L MIRROR 1 0.5 S ONBOARD ACQ FOR 11-52 CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 R136-OFFSET STIS/C ACQ/PEA 52X0.2 MIRROR 1 1.0 S ONBOARD ACQ FOR 11 - 52 CD K ------------------------------------------------------------------------------------------------------------------------------------ 11 R136-044 STIS/C ACCUM 52X0.2 G430M 4451 Pattern=ALONG-SLIT,NUM-POS=3, 1 1400 S CD STEP-SIZE=0.15 Comments: exposure time decreased from 1490x3 S ------------------------------------------------------------------------------------------------------------------------------------ 12 R136-044 STIS/C ACCUM 52X0.2 G750M 6581 1 600 S CD Comments: decreased from 650 ------------------------------------------------------------------------------------------------------------------------------------ 21 R136-007 STIS/C ACCUM 52X0.2 G750M 6581 1 130 S CD Comments: decreased from 135 ------------------------------------------------------------------------------------------------------------------------------------ 22 R136-007 STIS/C ACCUM 52X0.2 G430M 4451 Pattern=ALONG-SLIT,NUM-POS=3, 1 290 S CD STEP-SIZE=0.15 Comments: exposure time decreased from 3x310s ------------------------------------------------------------------------------------------------------------------------------------ 31 R136-020 STIS/C ACCUM 52X0.2 G430M 4451 Pattern=ALONG-SLIT,NUM-POS=3, 1 650 S CD STEP-SIZE=0.15 Comments: exposure time decreased from 712 ------------------------------------------------------------------------------------------------------------------------------------ 32 R136-020 STIS/C ACCUM 52X0.2 G750M 6581 1 280 S CD Comments: decreased from 300s ------------------------------------------------------------------------------------------------------------------------------------ 41 R136-036 STIS/C ACCUM 52X0.2 G750M 6581 1 490 S CD Comments: decreased from 530s ------------------------------------------------------------------------------------------------------------------------------------ 42 R136-036 STIS/C ACCUM 52X0.2 G430M 4451 Pattern=ALONG-SLIT,NUM-POS=3, 1 1150 S CD STEP-SIZE=0.15 Comments: exposure time decreased from 3x1240 ------------------------------------------------------------------------------------------------------------------------------------ 51 R136-047 STIS/C ACCUM 52X0.2 G430M 4451 Pattern=ALONG-SLIT,NUM-POS=3, 1 1550 S CD STEP-SIZE=0.15 Comments: exposure time decreased from 3x1633 ------------------------------------------------------------------------------------------------------------------------------------ 52 R136-047 STIS/C ACCUM 52X0.2 G750M 6581 1 660 S CD Comments: exposure time decreased from 712 ------------------------------------------------------------------------------------------------------------------------------------ 7739( 6) - 02/06/98 13:22 - [ 6] Visit: 02 Visit Priority: Visit Requirements: CVZ 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 ------------------------------------------------------------------------------------------------------------------------------------ 55 R136-OFFSET STIS/C ACQ F28X50L MIRROR 1 0.5 S ONBOARD ACQ FOR 56 CD P ------------------------------------------------------------------------------------------------------------------------------------ 56 R136-OFFSET STIS/C ACQ/PEA 52X0.2 MIRROR 1 1.0 S ONBOARD ACQ FOR 61-201 CD K ------------------------------------------------------------------------------------------------------------------------------------ 61 R136-018 STIS/C ACCUM 52X0.2 G750M 6581 1 295 S CD ------------------------------------------------------------------------------------------------------------------------------------ 62 R136-018 STIS/C ACCUM 52X0.2 G430M 4451 Pattern=ALONG-SLIT,NUM-POS=3, 1 690 S CD STEP-SIZE=0.15 Comments: exposure time decreased from 3x713 ------------------------------------------------------------------------------------------------------------------------------------ 71 R136-024 STIS/C ACCUM 52X0.2 G430M 4451 Pattern=ALONG-SLIT,NUM-POS=3, 1 825 S CD STEP-SIZE=0.15 Comments: exposure time decreased from 3x857 ------------------------------------------------------------------------------------------------------------------------------------ 72 R136-024 STIS/C ACCUM 52X0.2 G750M 6581 1 370 S CD ------------------------------------------------------------------------------------------------------------------------------------ 81 R136-040 STIS/C ACCUM 52X0.2 G750M 6581 1 580 S CD ------------------------------------------------------------------------------------------------------------------------------------ 82 R136-040 STIS/C ACCUM 52X0.2 G430M 4451 Pattern=ALONG-SLIT,NUM-POS=3, 1 1330 S CD STEP-SIZE=0.15 Comments: exposure time decreased from 3x1360 ------------------------------------------------------------------------------------------------------------------------------------ 91 R136-055 STIS/C ACCUM 52X0.2 G430M 4451 Pattern=ALONG-SLIT,NUM-POS=3, 1 1750 S CD STEP-SIZE=0.15 Comments: exposure time decreased from 3x1800s ------------------------------------------------------------------------------------------------------------------------------------ 92 R136-055 STIS/C ACCUM 52X0.2 G750M 6581 1 775 S CD ------------------------------------------------------------------------------------------------------------------------------------ 200 R136-115 STIS/C ACCUM 52X0.2 G430L 4300 1 950 S CD Comments: exposure time decreased from 1000s ------------------------------------------------------------------------------------------------------------------------------------ 201 R136-123 STIS/C ACCUM 52X0.2 G430L 4300 1 950 S CD Comments: exposure time decreased from 1030 ------------------------------------------------------------------------------------------------------------------------------------ 7739( 6) - 02/06/98 13:22 - [ 7] Summary Form for Proposal 7739 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters Pattern=ALONG-SLIT NUM-POS=3 STEP-SIZE=0.15 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO/CAR ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ ONBOARD ACQ FOR 11-52 ONBOARD ACQ FOR 11 - 52 ONBOARD ACQ FOR 56 ONBOARD ACQ FOR 61-201 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G430M G750M G430L ------------------------------------------------------------------------------------------------------------------------------------ Target Names R136-OFFSET R136-044 R136-007 R136-020 R136-036 R136-047 R136-018 R136-024 R136-040 R136-055 R136-115 R136-123 ------------------------------------------------------------------------------------------------------------------------------------