6032( 0) - 07/18/95 19:27 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6032 Version: ********** Check-in Date: ********** 1.Proposal Title: The Upper IMF in the Magellanic Clouds. II. Spatially Resolved Spectroscopy of New Compact Multiple Systems ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Hot Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Nolan R. Walborn Space Telescope Science Institute CoI: Laurent Drissen Laval University N CoI: Daniel J. Lennon Munich University N CoI: John W. MacKenty Space Telescope Science Institute N CoI: Joel Wm. Parker Goddard Space Flight Center N CoI: Abhijit Saha Space Telescope Science Institute N CoI: Richard L. White Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract Spectroscopy of a compact WN+OB group in the 30 Doradus periphery will be performed with FOS, to pursue a study of the upper IMF begun with WF/PC UBV images in Cycle 3, which newly resolved it into multiple stellar components. These observations will provide information relevant to the upper stellar mass limit, as well as the evolutionary relationships between the peculiar objects and their normal OB companions. The spectroscopy is also essential to define the upper HRD and IMF, since the temperatures and masses of O stars are indeterminate from continuum measurements such as UBV photometry alone. Previous ground-based spectroscopy has integrated over several comparable components in this object; only the optically corrected HST/FOS can observe the spectra of the WN stars and their OB companions separately. About a dozen components in this group will be observed and analyzed to determine their individual physical parameters and collective evolutionary status. ------------------------------------------------------------------------------------ 6032( 0) - 07/18/95 19:27 - [ 2] Observations Description ------------------------ We propose to observe the spectra of 11 members of the compact multiple system Breysacher 73 in the 30 Dor B region. UBV magnitudes have been measured from the Cycle 3 WF/PC images and used to calculate the spectroscopic exposure times. The relevant magnitudes are in the 14-16 range; we require the 0.3" aperture due to crowding for most stars and S/N = 70 to compensate the relatively low G400H resolution for blue-violet spectral classification and atmospheric analysis. Our detailed target-acquisition strategies, exposure- time estimates, and resultant orbit requirements are as follows. Target acquisition strategy: Since the relative positions of the stars in the cluster are known to within 0.03" from our Cycle 3 WF/PC images, we can use offsets to move the telescope from one star to the next. We will use a cluster member as an offset star. This star (30DorB-7; V=14.85) is 2.5" away from any other star. It will be acquired with a 3-stage PEAKUP (using the 1.0 aperture, and then the 0.3" twice); then a spectrogram will be obtained. The telescope will then slew from star to star within the cluster. Since the stars are all within a few arcseconds of each other, the error due to the slew movement is negligible. In order to make sure that the stars are always well centered, we will re-acquire the offset star once (orbit 5). We will also perform an ACQ/PEAK with the 0.3 aperture (3 X 3-0.05" steps) for 3 stars (1A, 1B, and 5) in very crowded regions. Spectra of relatively isolated stars (7, 6, 4, and 3) will be obtained with a larger aperture to decrease the exposure times and avoid more peak-up acquisitions. Because (a) Fig 1.2.1 in the FOS manual can no longer be used, the exposure times have to be increased by 30% to get the desired S/N ratio, and (b) the overheads and the acquisition take longer than estimated in phase I, one more orbit than the number allocated (8) would be necessary to complete our project. The total number of orbits is now 9. If it becomes impossible to schedule the 9th orbit without crossing the SAA, the last star to be observed (30DorB-6), and only this one, may be dropped from the target list. Example of exposure time calculation: According to the FOS manual, the count rate is given by Figure 1.2.3: for the 1.0 aperture and a source with F=1.0e-14 erg cm^-2 s^-1 A^-1 (corresponding to B=14.5, as for star 30DorB-2A), one gets 8 counts/s/diode. According to Figure 1.2.2, the transmission of the 0.3 aperture is (0.8/0.93=) 0.85 that of the 1.0 aperture, or 6.8 counts/s/diode. To get a S/N ratio of 70 per diode, we need to integrate for t = 70^2 / 6.8 = 720 s = 12 min. Real Time Justification ----------------------- Our targets lie within the southern CVZ and we hope they might be scheduled as such; however, we are requesting non- CVZ orbit resources because the tables in the Proposal Instructions show only two 24-hr CVZ periods during the example year at our positions, and we do not wish to risk potential non-schedulability. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6032( 0) - 07/18/95 19:27 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6032( 0) - 07/18/95 19:27 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 30DorB- EXT-STAR RA=5H 37M 47.12S +/- 0.05S, DEC= 2000 V=14.85 +/- 0.1 OFFSET -69D 09' 08.84" +/- 0.3" B-V=0.13 Comments: Coordinates are from WF/PC image w1fk0506t.c0h; 2 30DorB-1A EXT-STAR RA-OFF = -0.91S +/- 0.01S, DEC- 2000 V=14.68 +/- 0.1 OFF = -2.73" +/- 0.05", FROM 1 B-V=0.31 Comments: Offsets measured from WF/PC image w1fk0506t.c0h, Target name from Walborn et al (Feb 1, 1995 ApJLet) 3 30DorB-1B EXT-STAR RA-OFF = -0.85S +/- 0.01S, DEC- 2000 V=15.13 +/- 0.1 OFF = -2.49" +/- 0.05", FROM 1 B-V=0.14 Comments: Offsets measured from WF/PC image w1fk0506t.c0h, Target name from Walborn et al (1995, ApJLet) 4 30DorB-1C EXT-STAR RA-OFF = -0.84S +/- 0.01S, DEC- 2000 V=15.40 +/- 0.1 OFF = -3.68" +/- 0.05", FROM 1 B-V=0.19 Comments: Offsets measured from WF/PC image w1fk0506t.c0h, Target name from Walborn et al (1995, ApJLet) 5 30DorB-2A EXT-STAR RA-OFF = -0.575S +/- 0.01S, DEC- 2000 V=14.23 +/- 0.1 OFF = -1.19" +/- 0.05", FROM 1 B-V=0.0.27 Comments: Offsets measured from WF/PC image w1fk0506t.c0h, Target name from Walborn et al (1995, ApJLet) 6 30DorB-2B EXT-STAR RA-OFF = -0.53S +/- 0.01S, DEC- 2000 V=15.21 +/- 0.1 OFF = -0.65" +/- 0.05", FROM 1 B-V=0.10 Comments: Offsets measured from WF/PC image w1fk0506t.c0h, Target name from Walborn et al (1995, ApJLet) 7 30DorB-2C EXT-STAR RA-OFF = -0.50S +/- 0.01S, DEC- 2000 V=15.40 +/- 0.1 OFF = -1.84" +/- 0.05", FROM 1 B-V=0.29 Comments: Offsets measured from WF/PC image w1fk0506t.c0h, Target name from Walborn et al (1995, ApJLet) 8 30DorB-3 EXT-STAR RA-OFF = -0.985S +/- 0.01S, DEC- 2000 V=14.26 +/- 0.1 OFF = -1.09" +/- 0.05", FROM 1 B-V=0.22 Comments: Offsets measured from WF/PC image w1fk0506t.c0h, Target name from Walborn et al (1995, ApJLet) 9 30DorB-4 EXT-STAR RA-OFF = -0.679S +/- 0.01S, DEC- 2000 V=15.31 +/- 0.1 OFF = -4.42" +/- 0.05", FROM 1 B-V=0.06 Comments: Offsets measured from WF/PC image w1fk0506t.c0h, Target name from Walborn et al (1995, ApJLet) 10 30DorB-5 EXT-STAR RA-OFF = -0.376S +/- 0.01S, DEC- 2000 V=15.34 +/- 0.1 OFF = -3.53" +/- 0.05", FROM 1 B-V=0.02 Comments: Offsets measured from WF/PC image w1fk0506t.c0h, Target name from Walborn et al (1995, ApJLet) 11 30DorB-6 EXT-STAR RA-OFF = -1.338S +/- 0.01S, DEC- 2000 V=15.49 +/- 0.1 OFF = -5.59" +/- 0.05", FROM 1 B-V=-0.09 Comments: Offsets measured from WF/PC image w1fk0506t.c0h, Target name from Walborn et al (1995, ApJLet) 6032( 0) - 07/18/95 19:27 - [ 5] Visit: 01 Visit Requirements: 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 30DorB- FOS/RD ACQ/PEA 1.0 G400H SCAN-STEP- 1 0.5S ONBOARD ACQ FOR 2 OFFSET K X=0.60, SCAN- STEP-Y=0.60, SEARCH-SIZE- X=5, SEARCH- Comments: SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 2 30DorB- FOS/RD ACQ/PEA 0.3 G400H SCAN-STEP- 1 0.5S ONBOARD ACQ FOR 3 OFFSET K X=0.17, SCAN- STEP-Y=0.17, SEARCH-SIZE- X=5, SEARCH- Comments: SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 3 30DorB- FOS/RD ACQ/PEA 0.3 G400H SCAN-STEP- 1 5S ONBOARD ACQ FOR 4 OFFSET K X=0.05, SCAN- STEP-Y=0.05, SEARCH-SIZE- X=5, SEARCH- Comments: SIZE-Y=5 ------------------------------------------------------------------------------------------------------------------------------------ 4 30DorB- FOS/RD ACCUM 0.5 G400H 1 900S OFFSET ------------------------------------------------------------------------------------------------------------------------------------ 5 30DorB-2B FOS/RD ACCUM 0.3 G400H 1 1500S ------------------------------------------------------------------------------------------------------------------------------------ 6 30DorB-2A FOS/RD ACCUM 0.3 G400H 1 720S ------------------------------------------------------------------------------------------------------------------------------------ 7 30DorB-2C FOS/RD ACCUM 0.3 G400H 1 2100S ------------------------------------------------------------------------------------------------------------------------------------ 8 30DorB-1C FOS/RD ACCUM 0.3 G400H 1 1800S ------------------------------------------------------------------------------------------------------------------------------------ 9 30DorB- FOS/RD ACQ/PEA 0.3 G400H SCAN-STEP- 1 5S ONBOARD ACQ FOR 10 OFFSET K X=0.05, SCAN- STEP-Y=0.05, SEARCH-SIZE- X=3, SEARCH- Comments: SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 10 30DorB-1A FOS/RD ACQ/PEA 0.3 G400H SCAN-STEP- 1 5S ONBOARD ACQ FOR 11 K X=0.05, SCAN- STEP-Y=0.05, SEARCH-SIZE- X=3, SEARCH- Comments: SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 6032( 0) - 07/18/95 19:27 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 11 30DorB-1A FOS/RD ACCUM 0.3 G400H 1 1140S ------------------------------------------------------------------------------------------------------------------------------------ 12 30DorB-1B FOS/RD ACQ/PEA 0.3 G400H SCAN-STEP- 1 7S ONBOARD ACQ FOR 13 K X=0.05, SCAN- STEP-Y=0.05, SEARCH-SIZE- X=3, SEARCH- Comments: SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 13 30DorB-1B FOS/RD ACCUM 0.3 G400H 1 1500S ------------------------------------------------------------------------------------------------------------------------------------ 14 30DorB-4 FOS/RD ACCUM 0.5 G400H 1 1380S ------------------------------------------------------------------------------------------------------------------------------------ 15 30DorB-3 FOS/RD ACCUM 0.5 G400H 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 16 30DorB-5 FOS/RD ACQ/PEA 0.3 G400H SCAN-STEP- 1 7S ONBOARD ACQ FOR 17 K X=0.05, SCAN- STEP-Y=0.05, SEARCH-SIZE- X=3, SEARCH- Comments: SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 17 30DorB-5 FOS/RD ACCUM 0.3 G400H 1 1200S ------------------------------------------------------------------------------------------------------------------------------------ 18 30DorB-6 FOS/RD ACCUM 0.5 G400H 1 1500S ------------------------------------------------------------------------------------------------------------------------------------ 6032( 0) - 07/18/95 19:27 - [ 7] Summary Form for Proposal 6032 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/RD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SCAN-STEP-X=0.60 SCAN-STEP-Y=0.60 SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 SCAN-STEP-Y=0.17 SCAN-STEP-Y=0.05 SEARCH-SIZE-Y=3 SEARCH-SIZE-X=3 SCAN-STEP-X=0.05 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Hot Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 4 ONBOARD ACQ FOR 10 ONBOARD ACQ FOR 11 ONBOARD ACQ FOR 13 ONBOARD ACQ FOR 17 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G400H ------------------------------------------------------------------------------------------------------------------------------------ Target Names 30DorB-OFFSET 30DorB-2B 30DorB-2A 30DorB-2C 30DorB-1C 30DorB-1A 30DorB-1B 30DorB-4 30DorB-3 30DorB-5 30DorB-6 ------------------------------------------------------------------------------------------------------------------------------------