11784( 8) - 17-Nov-2009 15:17:34 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11784 Version: 8 Check-in Time: 17-Nov-2009 15:17:34 STScI Edit Number: 4 Title The orbit of the most massive known astrometric binary ------------------------------------------------------------------------------------ Type Cycle GO 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Jesus Maiz Apellaniz Instituto de Astrofisica de Andalucia (IAA) CoI: Dr. Edmund Nelan Space Telescope Science Institute N CoI: Dr. Nolan R. Walborn Space Telescope Science Institute N CoI: Dr. Nidia Morrell Carnegie Institution of Washington N CoI: Dr. Paula Benaglia Universidad Nacional de La Plata (UNLP) N CoI: Mr. Alfredo Sota Instituto de Astrofisica de Andalucia N (IAA) ------------------------------------------------------------------------------------ Abstract We have recently used FGS and HRC observations to (a) resolve HD 93129A into two components with very similar optical/UV colors and a magnitude difference of 0.9 and to (b) detect their relative orbital motion over a span of 8 years. HD 93129Aa is the prototype O2 If* star, with an evolutionary mass near 100 M_Sun, while Ab is likely to be a very early O main-sequence star with a similar or only slightly smaller mass. Our HST astrometric measurements yield a total mass above 100 M_Sun, thus confirming the extremely high mass of the binary, and indicate that the system appears to be approaching periastron. We request new FGS and HRC observations to (a) calculate the mass ratio of the system by measuring the orbit of each of the components with respect to the nearby stars, (b) obtain the periastron epoch, and (c) start measuring the orbit in order to produce an estimate of the total mass. These measurements are crucial to shed light on the value of the stellar upper mass limit. Due the the non-recovery of HRC on SM4, the last visit was changed to STIS. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose observing HD 93129 at three different epochs using ACS/HRC and FGS. Due the the non-recovery of HRC on SM4, the last visit was changed to STIS. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 11784( 8) - 17-Nov-2009 15:17:34 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD93129A STAR, OF, SUPERGIANT O, RA=10H43M57.4620S +/- 0.1", J2000 V = 7.3 +/- 0.1 O2 If* WIND DEC=-59D32'51.27" +/- 0.1" Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 11784( 8) - 17-Nov-2009 15:17:34 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.025 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.035 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 45 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 11784( 8) - 17-Nov-2009 15:17:34 - [ 4] Visit: 01 Visit Requirements: ORIENT 59D TO 59 D; ORIENT 239D TO 239 D; BEFORE 01-JUN-2010:00:00:00 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD93129A STIS/CCD ACQ F28X50OII MIRROR 1 0.2 S GS ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 HD93129A STIS/CCD ACCUM F28X50OII MIRROR CR-SPLIT=NO, GAIN=4 1 2 S PATTERN 2 2 I ------------------------------------------------------------------------------------------------------------------------------------ 3 HD93129A STIS/CCD ACCUM 52X0.2E1 G430M 4706 CR-SPLIT=NO, GAIN=4 1 74 S PATTERN 1 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 HD93129A STIS/CCD ACCUM 52X0.2E1 G430M 4451 CR-SPLIT=NO, GAIN=4 1 74 S PATTERN 1 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 HD93129A STIS/CCD ACCUM 52X0.2E1 G430M 4194 CR-SPLIT=NO, GAIN=4 1 74 S PATTERN 1 5 ------------------------------------------------------------------------------------------------------------------------------------ 6 HD93129A STIS/CCD ACCUM 52X0.2E1 G430M 3936 CR-SPLIT=NO, GAIN=4 1 74 S PATTERN 1 6 ------------------------------------------------------------------------------------------------------------------------------------ 7 HD93129A STIS/CCD ACCUM 52X0.2E1 G750M 6768 CR-SPLIT=NO, GAIN=4 1 38 S PATTERN 1 7 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ HD93129A 1 STIS/CCD ACQ F28X50OI MIRROR none none none none 1 N/A I HD93129A 2 STIS/CCD ACCUM F28X50OI MIRROR 1 none none none 1 N/A II HD93129A 2 STIS/CCD ACCUM F28X50OI MIRROR 2 none none none 1 N/A II HD93129A 3 STIS/CCD ACCUM 52X0.2E1 G430M 4706 1 none none none 1 N/A HD93129A 3 STIS/CCD ACCUM 52X0.2E1 G430M 4706 2 none none none 1 N/A HD93129A 4 STIS/CCD ACCUM 52X0.2E1 G430M 4451 1 none none none 1 N/A HD93129A 4 STIS/CCD ACCUM 52X0.2E1 G430M 4451 2 none none none 1 N/A HD93129A 5 STIS/CCD ACCUM 52X0.2E1 G430M 4194 1 none none none 1 N/A HD93129A 5 STIS/CCD ACCUM 52X0.2E1 G430M 4194 2 none none none 1 N/A HD93129A 6 STIS/CCD ACCUM 52X0.2E1 G430M 3936 1 none none none 1 N/A HD93129A 6 STIS/CCD ACCUM 52X0.2E1 G430M 3936 2 none none none 1 N/A HD93129A 7 STIS/CCD ACCUM 52X0.2E1 G750M 6768 1 none none none 1 N/A HD93129A 7 STIS/CCD ACCUM 52X0.2E1 G750M 6768 2 none none none 1 N/A 11784( 8) - 17-Nov-2009 15:17:34 - [ 5] Visit: 51 Visit Requirements: ORIENT 59D TO 59 D; ORIENT 239D TO 239 D; BEFORE 01-JUN-2010:00:00:00 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD93129A STIS/CCD ACQ F28X50OII MIRROR 1 0.2 S GS ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 HD93129A STIS/CCD ACCUM F28X50OII MIRROR CR-SPLIT=NO, GAIN=4 1 2 S PATTERN 2 2 I ------------------------------------------------------------------------------------------------------------------------------------ 3 HD93129A STIS/CCD ACCUM 52X0.2E1 G430M 4706 CR-SPLIT=NO, GAIN=4 1 74 S PATTERN 1 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 HD93129A STIS/CCD ACCUM 52X0.2E1 G430M 4451 CR-SPLIT=NO, GAIN=4 1 74 S PATTERN 1 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 HD93129A STIS/CCD ACCUM 52X0.2E1 G430M 4194 CR-SPLIT=NO, GAIN=4 1 74 S PATTERN 1 5 ------------------------------------------------------------------------------------------------------------------------------------ 6 HD93129A STIS/CCD ACCUM 52X0.2E1 G430M 3936 CR-SPLIT=NO, GAIN=4 1 74 S PATTERN 1 6 ------------------------------------------------------------------------------------------------------------------------------------ 7 HD93129A STIS/CCD ACCUM 52X0.2E1 G750M 6768 CR-SPLIT=NO, GAIN=4 1 38 S PATTERN 1 7 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ HD93129A 1 STIS/CCD ACQ F28X50OI MIRROR none none none none 1 N/A I HD93129A 2 STIS/CCD ACCUM F28X50OI MIRROR 1 none none none 1 N/A II HD93129A 2 STIS/CCD ACCUM F28X50OI MIRROR 2 none none none 1 N/A II HD93129A 3 STIS/CCD ACCUM 52X0.2E1 G430M 4706 1 none none none 1 N/A HD93129A 3 STIS/CCD ACCUM 52X0.2E1 G430M 4706 2 none none none 1 N/A HD93129A 4 STIS/CCD ACCUM 52X0.2E1 G430M 4451 1 none none none 1 N/A HD93129A 4 STIS/CCD ACCUM 52X0.2E1 G430M 4451 2 none none none 1 N/A HD93129A 5 STIS/CCD ACCUM 52X0.2E1 G430M 4194 1 none none none 1 N/A HD93129A 5 STIS/CCD ACCUM 52X0.2E1 G430M 4194 2 none none none 1 N/A HD93129A 6 STIS/CCD ACCUM 52X0.2E1 G430M 3936 1 none none none 1 N/A HD93129A 6 STIS/CCD ACCUM 52X0.2E1 G430M 3936 2 none none none 1 N/A HD93129A 7 STIS/CCD ACCUM 52X0.2E1 G750M 6768 1 none none none 1 N/A HD93129A 7 STIS/CCD ACCUM 52X0.2E1 G750M 6768 2 none none none 1 N/A 11784( 8) - 17-Nov-2009 15:17:34 - [ 6] Summary Form for Proposal 11784 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2E1, F28X50OII, F28X50OIII ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO, GAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BEFORE 01-JUN-2010:00:00:00, GS ACQ SCENARIO BASE1B3, ORIENT 239D TO 239 D, ORIENT 59D TO 59 D, PATTERN 1 3, PATTERN 1 4, PATTERN 1 5, PATTERN 1 6, PATTERN 1 7, PATTERN 2 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G430M, G750M, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD93129A ------------------------------------------------------------------------------------------------------------------------------------