Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1188c Report Date: 09-May-96:16:17 Version: ********** Check-in Date: ********** 1.Proposal Title: UV SPECTROSCOPY OF THE COMPONENTS OF R136 -- CYCLE 0 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR ASTROPHYSICS GTO/HRS Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. Dennis C. Ebbets BALL AEROSPACE CORPORATION USA (303) 939-5964 PRIN MEM TECH STAFF ------------------------------------------------------------------------------------ 7. Abstract R136 is the bright central object of the 30 Doradus nebula in the LMC. It contains an unusually tight grouping of very massive and luminous O and Wolf-Rayet type stars. The brightest recognizeable component, called R136A1, may be an unresolved group of several stars, or may be a single object with a mass of order 800 Mo. Detailed studies of the individual components have been hampered by a lack of sufficient spatial resolution. The High Resolution Spectrograph will be used to obtain detailed ultraviolet spatial and spectral information about the five or so brightest discrete components. The goal of the program is to study the spectral morphology, stellar wind characteristics, ultraviolet luminosities and ultimately the masses included in this unusual and interesting object. redlined for phase 2, 7/19/88, dce updated for cycle 1 phase 2 9/21/89 revised lines 1-7 for cycle zero 11/15/90 ------------------------------------------------------------------------------------ 8. Scientific Key Words: SUPERGIANT STAR, WOLF-RAYET STAR, MASS LOSS, LMC 30 DORADUS ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 7.80 par: 0 10. Num targs pri: 9 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 1188c PI: Dr. Dennis C. Ebbets Proposal Title: UV SPECTROSCOPY OF THE COMPONENTS OF R136 -- CYCLE 0 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Blair D. Savage WISCONSIN, UNIVERSITY OF USA Dennis C. Ebbets BALL AEROSPACE CORPORATION USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. There are three sets of observations in this program. The first consists of multiple observations of R136a1, obtained with grating configuration G140L, spaced over the 2 1/2 years of the GTO period. The purpose is to investigate the possibility of spectrum variablity with very high quality data. The second set consists of spectra of the other compnents of R136. We plan to observe R136a2, R136b, and R136c, also with G140L. Time is also allocated for an observation of the "fuzz", which shows an O type optical spectrum. The objective is to study in detail the spectra of each discrete component, using the spatial resolution povided by the HRS small science aperture. The third set of observations will study the profiles of selected stellar and interstellar lines in the brightest component, R136a1, using the HRS medium resolution grating G160M. The prominent stellar wind lines of OV, CIV, HeII and NIV will be observed, along with photospheric FeV, interstellar SiIV, and other interstellar components in the spectral regions observed. Cycle 0: Exposures 1-7 1.09 hours priority=2 Cycle 1: Exposures 12-22, 26-30 2.39 hours priority=2 Cycle 2: Exposures 32.5-40 2.83 hours priority=1,2 Cycle 3: Exposures 41-45, 23-25, 45.5-53 1.49 hours priority=2,3 Total = 7.80 hours ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. R136 has been studied extensively from the ground with imagery and spectroscopy. Over a dozen observations have been made with the IUE. Much has been learned from these studies, but all have been ultimately limited by the finite spatial resolution allowed by the atmosphere and the instruments. ST will produce images (not part of this proposal) with much finer spatial resolution, and will provide vastly superior data related to the number, distribution and nature of the components. The HRS will have the spatial resolution, sensitivity and spectral resolving power to provide high quality ultraviolet spectra of each component. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. R136 is a very crowded field. Successful completion of this program requires that the component being observed be precisely centered in the 0.25 arc sec aperture. We request real time target acquisition capability, to ensure that the centering is adequate, and to make adjustments to the pointing if necessary. The basic capablility for acquiring targets in complex fields should have been developed during SV, using R136 as a verification target. See SV tests HRS-04 "HRS Spiral Search Pattern" and HRS-06 "Mode I Target Acquisition With HRS Maps. Page 3 ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The spectra will be calibrated and reduced using standard procedures either in RSDP, or the IDT facilities. The time series on R136a1 will be carefully examined for variability, particularly in the CIV and HeII stellar wind lines. The spectra of all components will be studied in terms of gross spectral morphologhy, for the purposes of classification. Stellar wind diagnostics such as terminal velocities and mass loss rates will be derived from comparison of line profiles with model predictions and experience with similar stars. The ultraviolet spectral energy distributions will be studied by correcting for now known effects of galactic and LMC extinction. Profiles, equivalent widths and velocity components of interstellar lines will be derived from the medium resoultion observations. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. The ability to acquire point source targets in complex fields, including the use of HRS field maps, must have been verified and perfected before these observations can proceed. Similarly, the ability to execute small offset maneuvers to sequentially observe a number of close targets must have been verified. ------------------------------------------------------------------------------------ 9. Description of previous HST work. Both Ebbets and Savage are involved in several GTO programs. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Data reduction and analysis facilities, part time research assistant, manuscript preparation, publication costs, travel expenses. ------------------------------------------------------------------------------------ 12. The observations of R136a1 should be scheduled at three widely spaced intervals. SV Prerequisites HRS 05.3 Mode II Target Acquisition - offet or functional equivalent HRS 06 Mode I Target Acquisition with HRS Maps HRS 08 HRS Low Resolution Calibration ------------------------------------------------------------------------------------ 13. The High Resolution Spectrograph will be used to observe the UV spectrum of the bright components of R136. The brightest member, R136a1 will be observed 4 times to search for variability over a 2 1/2 period. All other componets wil be observed once. Several prominent stellar wind lines, and a few important interstellar regions will be observed with the medium resolution R=20000 grating. ------------------------------------------------------------------------------------ 11. Address Information Name: BLAIR D. SAVAGE Category: CON Institution: UNIVERSITY OF WISCONSIN Address: DEPARTMENT OF ASTRONOMY 475 N. CHARTER ST. City: MADISON State: WI Zip Code: 53706 Country: USA Telephone: (608) 262-4909 Telex (or e-mail): ------------------------------------------------------------------------------------ Name: DENNIS C. EBBETS Category: PI Institution: BALL AEROSPACE SYSTEMS GROUP Address: GHRS PROJECT AR-1 P.O. BOX 1062 City: BOULDER State: CO Zip Code: 80306 Country: USA Telephone: (303) 939-5964 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 1188c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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 BRIGHTEST COMPONENT OF RA = 5H 38M 42.50S +/- 0.1S, 2000 COMP 1 V = 10.1 HD38268 R136 DEC = -69D 06' 02.8" +/- 1" 2 F-CONT(1500) = 6.2 E-13 Comments: POSITION FROM PC IMAGE MEASURED BY ARCHIE BETWEEN A1 AND A2 UV CONTINUUM FLUXES ESTIMATED FROM IUE OBSERVATIONS OF TOTAL FLUX AND RATIOS OF COMPONENT BRIGHTNESSES IN VISIBLE LIGHT. GS PLATE ID = 06B0 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1188c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 R136A1 HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=5 1 1325S 1 2 INT ACQ FOR 2-7 CYCLE 0 / 1-7 SEQ 1-7 NO GAP Comments: EARLY ACQ FOR 12,32.5,41; ------------------------------------------------------------------------------------------------------------------------------------ 2 R136A1 HRS IMAGE 2.0 MIRROR-N2 1 96.8S 1 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 R136A1 HRS IMAGE 2.0 MIRROR-N1 1 484S 1 2 ------------------------------------------------------------------------------------------------------------------------------------ 4 R136A1 HRS ACCUM 2.0 G140L 1200 STEP-PATT=2 2 10M 50 2 2 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 5 R136A1 HRS ACCUM 2.0 G140L 1450 STEP-PATT=2 1 10M 50 2 2 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 6 R136A1 HRS ACCUM 2.0 G140L 1700 STEP-PATT=2 2 8M 50 2 2 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 7 R136A1 HRS IMAGE 2.0 MIRROR-N1 1 484S 1 2 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1188c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ IMAGE ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE=5 STEP-PATT=2 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/HRS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 7.80 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR ASTROPHYSICS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements INT ACQ FOR 2-7; CYCLE 0 / 1-7; SEQ 1-7 NO GAP; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 MIRROR-N1 G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names R136A1 HD38268 ------------------------------------------------------------------------------------------------------------------------------------