6133( 0) - 07/18/95 20:14 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6133 Version: ********** Check-in Date: ********** 1.Proposal Title: The most massive stars in the Magellanic Clouds ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Hot Stars SNAP 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Rolf-Peter Kudritzki Universitaets-Sternwarte Muenchen CoI: Daniel Lennon Universitaets-Sternwarte Muenchen Y ------------------------------------------------------------------------------------ 6. Abstract The analysis of high quality visual and uv (HST) spectrograms for a number of massive O-stars in the Magellanic Clouds has led to the conclusion that stellar masses for these objects may be as high as 200Msun . The radii and masses have been derived using apparent magnitudes determined from ground-based photometry and assuming that each object is single. Given the past history of supermassive stars (R136a for example) breaking up into multiple objects under the scrutiny of HST we propose obtaining high resolution images with WFPC2 for the most massive stars in our sample in order to verify that they are indeed single objects. If particular if singularity is confirmed for Sk-67 211 then we estimate that this object is the most massive star known. ------------------------------------------------------------------------------------ Observations Description ------------------------ We plan to observe each object with WFPC2 and the F555W filter and using equation 6.1 of the WFPC2 handbook and allowing for the fact that one pixel in the PC detects a maximum of 20% of the total photons in the PSF the exposure time (2 seconds) is estimated to avoid saturating a 12th magnitude O-star (all targets are fainter than this). Thus the required space- craft times will essentially be overhead times (3 minutes per star). Also in view of the brevity of exposure times the observations may be carried out under gyro control and guide star acquisition is not required. No proprietary data rights are requested. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6133( 0) - 07/18/95 20:14 - [ 2] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6133( 0) - 07/18/95 20:14 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SK-67D211 STAR,GIANT O RA=05H 35M 13.921S +/- 0.50", 2000.0 V=+303 V=12.28 B-V=-0.23 E(B-V)=0.10 DEC=-67D 33' 27.46" +/- 0.50", PLATE-ID=05ZW 2 SK-68D137 STAR,GIANT O RA=05H 38M 24.776S +/- 0.50", 2000.0 V=+280 V=13.19 B-V=-0.19 E(B-V)=0.14 DEC=-68D 52' 32.81" +/- 0.50", PLATE-ID=05ZW 3 SK-66D172 STAR,GIANT O RA=05H 37M 05.588S +/- 0.50", 2000.0 V=+280 V=13.13 B-V=-0.12 E(B-V)=0.20 DEC=-66D 21' 35.94" +/- 0.50" 4 SK-67D166 STAR,SUPERGIANT O RA=05H 31M 44.299S +/- 0.50", 2000.0 V=+303 V=12.27 B-V=-0.22 E(B-V)=0.09 DEC=-67D 38' 01.02" +/- 0.50", PLATE-ID=05ZW 5 SK-67D167 STAR,SUPERGIANT O RA=05H 31M 51.984S +/- 0.50", 2000.0 V=+280 V=12.54 B-V=-0.19 E(B-V)=0.12 DEC=-67D 39' 41.14" +/- 0.50", PLATE-ID=05ZW 6 SK-70D69 STAR,MAIN SEQUENCE O RA=05H 05M 18.769S +/- 0.50", 2000.0 V=+280 V=13.90 B-V=-0.31 E(B-V)=0.02 DEC=-70D 25' 49.91" +/- 0.50", PLATE-ID=05ZW 7 AV488 STAR,SUPERGIANT O RA=01H 15M 58.838S +/- 0.50", 2000.0 V=11.90 B-V=-0.13 U-B=-0.97 DEC=-73D 21' 24.14" +/- 0.50", PLATE-ID=06B1 6133( 0) - 07/18/95 20:14 - [ 4] Visit: 01 Visit Requirements: PCS MODE Fine 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 SK-67D211 WFPC2 IMAGE PC1 F555W 1 2S ------------------------------------------------------------------------------------------------------------------------------------ 6133( 0) - 07/18/95 20:14 - [ 5] Visit: 02 Visit Requirements: PCS MODE Fine 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 SK-68D137 WFPC2 IMAGE PC1 F555W 1 2S ------------------------------------------------------------------------------------------------------------------------------------ 6133( 0) - 07/18/95 20:14 - [ 6] Visit: 03 Visit Requirements: PCS MODE Fine 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 SK-66D172 WFPC2 IMAGE PC1 F555W 1 2S ------------------------------------------------------------------------------------------------------------------------------------ 6133( 0) - 07/18/95 20:14 - [ 7] Visit: 04 Visit Requirements: PCS MODE Fine 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 SK-67D166 WFPC2 IMAGE PC1 F555W 1 2S ------------------------------------------------------------------------------------------------------------------------------------ 6133( 0) - 07/18/95 20:14 - [ 8] Visit: 05 Visit Requirements: PCS MODE Fine 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 SK-67D167 WFPC2 IMAGE PC1 F555W 1 2S ------------------------------------------------------------------------------------------------------------------------------------ 6133( 0) - 07/18/95 20:14 - [ 9] Visit: 06 Visit Requirements: PCS MODE Fine 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 SK-70D69 WFPC2 IMAGE PC1 F555W 1 2S ------------------------------------------------------------------------------------------------------------------------------------ 6133( 0) - 07/18/95 20:14 - [ 10] Visit: 07 Visit Requirements: PCS MODE Fine 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 AV488 WFPC2 IMAGE PC1 F555W 1 2S ------------------------------------------------------------------------------------------------------------------------------------ 6133( 0) - 07/18/95 20:14 - [ 11] Summary Form for Proposal 6133 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category SNAP ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Hot Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE Fine ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SK-67D211 SK-68D137 SK-66D172 SK-67D166 SK-67D167 SK-70D69 AV488 ------------------------------------------------------------------------------------------------------------------------------------