Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5297 Report Date: 18-Jul-95:17:07 Version: ********** Check-in Date: ********** 1.Proposal Title: FIRST SPECTRA OF O STARS IN R136A ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR ASTROPHYSICS SMC/ERO Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Sara R. Heap NASA, GODDARD SPACE FLIGHT C USA 301-286-5359 ------------------------------------------------------------------------------------ 7. Abstract Hubble images of the cluster, R136a, in the LMC indicate that the cluster contains 3 Wolf-Rayet stars, R136a1,-a2, and a3 (Campbell et al. 1992) and numerous O and B- type stars. Although models for WR stars are not well enough developed to infer the basic parameters of the 3 WR stars in R136a, models for O stars are well well established, and they suggest that the O stars in R136a are relatively normal, having initial masses no higher than 60 Msun (Heap et al. 1992, Malumuth & Heap 1992, di Marchi et al. 1993); there are no unusual "super-massive" stars in R136a. With HST/GHRS/CoSTAR, it will be possible to obtain spectra of an O star in R136a without contam- ination by WR stars. These spectra will be able to confirm or invalidate the photometric results. Thus, these spectra will have implications both for the population of R136a and for the validity of stellar population studies of giant extragalactic HII regions and starbursts that are based entirely on photometry. ------------------------------------------------------------------------------------ 8. Scientific Key Words: HOT STARS, MASSIVE STARS, CLUSTERS ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 6.28 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5297 PI: Sara R. Heap Proposal Title: FIRST SPECTRA OF O STARS IN R136A ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Sara R. Heap NASA, GODDARD SPACE FLIGHT USA CENTER What_a_great Ghrs-Team NASA, GODDARD SPACE FLIGHT USA CENTER ------------------------------------------------------------------------------------ 3. Description of proposed observations. This program is similar to the first ERO program on Melnick 42: the target is similar (a hot, massive star in 30 Dor), it uses the same instrument (GHRS/Side1/G140L). In this case, there are two targets, R136a2 (presumably WN4.5) and R136a5 (presumably early O star). R136a5 is about 1 mag fainter than Mk 42, but the efficiency of the GHRS should be twice as high as before COSTAR, so this program uses the same exposure time on R136a5 as it did on Mk 42. The exposure times are 4 times shorter on R136a2, since we only need to confirm the spectral type and basic spectral features. This program will also yield excellent pictures of the R136a field in both N1 and N2, thus confirming the benefits of COSTAR for imaging. The observing strategy is the following. We first aquire a spot between R136a1 and R136a2. If the two stars are of equal brightness, then the spot will be half-way between and a distance of 0.053" from R136a1. We next slew to R136a2 and get a spectrum. By assuming the spot is really R136a1, we may have overshot R136a2 by 0.053, but that's okay. We next slew to R136a5 & get a spectrum. Again we may over shoot a little. Finally we get some UV maps. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The HST+CoSTAR/GHRS is needed to isolate individual stars in the very compact cluster, R136a. In this program, a spectrum of R136a5 will be obtained even though there is a brighter star, R136a2, less than 0.3" away ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. This program will undoubtedly be one of the first external observations with the GHRS using Side 1 since the summer of 1991. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The spectra will be reduced and analyzed at Goddard Space Flight Center. Modeling of the wind and estimation of the basic stellar parameters will be in collaboration with HST GTO's and GO's. ------------------------------------------------------------------------------------ 11. Address Information Name: SARA R. HEAP Category: PI Institution: GODDARD SPACE FLIGHT CENTER Address: CODE 681 City: GREENBELT State: MD Zip Code: 20771 Country: USA Telephone: 301-286-9545 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5297 [ 3] ------------------------------------------------------------------------------------------------------------------------------------ 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 R136a1 B,103,D,203 RA = 05H 38M 42.438S +/- 2000 1 V=12.77 0.1S, 2 B-V=+0.43 DEC = -69D 06' 02.294" +/- 0.5" Comments: V,B-V from Malumuth & Heap (1993) ------------------------------------------------------------------------------------------------------------------------------------ 2 R136a2 B,103,D,203 RA = 05H 38M 42.4576S +/- 2000 1 V=13.38 0.1S, 2 B-V=+0.43 DEC = -69D 06' 02.242" +/- 0.5" Comments: WN star in R136a; coordinates and V,B-V from Malumuth & Heap (1993) ------------------------------------------------------------------------------------------------------------------------------------ 5 R136a5 B,105,D,203 RA = 05H 38M 42.4785S +/- 2000 1 V=13.73 0.1S, 2 B-V=+0.12 DEC = -69D 06' 02.096" +/- 0.5" Comments: O star in R136a; coordinates and V,B-V from Malumuth & Heap (1993) ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5297 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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 R136a1 HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=5 1 25S 1 1 CYCLE 4/1-101 ONBOARD ACQ FOR 2- 3 SEQ 1-101 NO GAP Comments: Time=(128*Nmap +SS2)*StepT =(0 +5x5)*1.0S = 25S GHRS HDBK/Fig 7.3 gives N1 c/s=2500 for V=13.0, (B-V)o=-.3, E(B-V)=.4 BRIGHT=RETURN assumed ------------------------------------------------------------------------------------------------------------------------------------ 2 R136a1 HRS ACQ/ 2.0 MIRROR-N2 1 102S 1 1 CYCLE 4 PEAKUP Comments: Time=Fapt*StepT =102 * 1S ------------------------------------------------------------------------------------------------------------------------------------ 3 R136a1 HRS ACQ/ 0.25 MIRROR-N2 SEARCH-SIZE=5 1 25S 1 1 ONBOARD ACQ FOR 4- PEAKUP 52 Comments: Time=SSIZE^2 * StepT =25 * 1S BRIGHT=RETURN assumed ------------------------------------------------------------------------------------------------------------------------------------ 4 R136a1 HRS IMAGE 0.25 MIRROR-N2 NX=13 1 169S 1 1 NY=13 DELTA-X=1 DELTA-Y=1 Comments: Time=13*13*1S=169S ------------------------------------------------------------------------------------------------------------------------------------ 5 R136a2 HRS IMAGE 0.25 MIRROR-N2 NX=13 1 169S 1 1 NY=13 DELTA-X=1 DELTA-Y=1 Comments: Time=13*13*1S=169S ------------------------------------------------------------------------------------------------------------------------------------ 20 R136a2 HRS ACCUM 0.25 G140L 1300 STEP-PATT=3 1 10M 1 FP-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 21 R136a2 HRS ACCUM 0.25 G140L 1610 STEP-PATT=3 4 10M 1 FP-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ 50 R136a5 HRS ACCUM 0.25 G140L 1610 STEP-PATT=3 4 30M 1 FP-SPLIT=FOUR Comments: total texp=120M ------------------------------------------------------------------------------------------------------------------------------------ 51 R136a5 HRS ACCUM 0.25 G140L 1300 STEP-PATT=3 1 30M 1 FP-SPLIT=FOUR Comments: total texp=30M ------------------------------------------------------------------------------------------------------------------------------------ 52 WAVE HRS ACCUM SC2 G140L 1300 STEP-PATT=3 1 25.6S 1 FP-SPLIT=NO Comments: WAVECAL FOR SPECTRA ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5297 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 99 R136a5 HRS IMAGE 0.25 MIRROR-N2 NX=13 1 169S 1 1 NY=13 DELTA-X=1 DELTA-Y=1 Comments: Time=13*13*1S=169S ------------------------------------------------------------------------------------------------------------------------------------ 100 R136a5 HRS IMAGE 2.0 MIRROR-N2 NX=22 1 968S 1 1 NY=22 DELTA-X=2 DELTA-Y=2 Comments: Time=22*22*2S=968S ------------------------------------------------------------------------------------------------------------------------------------ 101 R136a5 HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=3 1 1161S 1 1 LOCATE=NO MAP=ALL-POINTS Comments: Time=(128*Nmap +SS2)*StepT =(128*9 +3X3)*1.0S=1161S ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5297 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP IMAGE ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE=5 NX=13 NY=13 DELTA-X=1 DELTA-Y=1 STEP-PATT=3 FP-SPLIT=NO FP-SPLIT=FOUR NX=22 NY=22 DELTA-X=2 DELTA-Y=2 SEARCH-SIZE=3 LOCATE=NO MAP=ALL-POINTS ------------------------------------------------------------------------------------------------------------------------------------ Proposal for SMC/ERO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 6.28 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR ASTROPHYSICS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4/1-101; ONBOARD ACQ FOR 2-3; SEQ 1-101 NO GAP CYCLE 4; ONBOARD ACQ FOR 4-52 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names R136a1 R136a2 R136a5 ------------------------------------------------------------------------------------------------------------------------------------