9691( 4) - 03/27/03 12:43 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9691 Version: 4 Check-in Date: 27-Mar-2003 12:42:39 1.Proposal Title: Resolution of the Source Star for a Candidate Planetary Gravitational Microlensing Event ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO/DD 11 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: David Bennett University of Notre Dame CoI: Dr. Ian Bond Royal Observatory, Edinburgh N CoI: Dr. Kem Cook Lawrence Livermore National Laboratory N CoI: Dr. Andrew Gould Ohio State University N CoI: Dr. Sun Hong Rhie University of Notre Dame N CoI: Dr. Phil Yock University of Auckland, New Zealand N ------------------------------------------------------------------------------------ 5. Abstract We propose ACS/HRC images of the microlensing event MOA-2002-BLG-33 which exhibited a light curve deviation from the normal single-lens microlensing light curve on July 4.65-5.28, 2002 UT. This light curve deviation may be due to either a planetary or stellar companion orbiting the lens star, and the deviation is very well characterized since the event was observed continuously by telescopes at 6 different longitudes. The source star for this microlensing event is very likely to be unresolved in ground-based images when it is not magnified by microlensing, and our observations are intended to determine the properties of the lens star. We request UBVI images both during and after the microlensing event in order to get accurate measurements of the color of the lensed source star and any stars that are not resolved from it, such as the lens star. ------------------------------------------------------------------------------------ 9691( 4) - 03/27/03 12:43 - [ 2] Observations Description ------------------------ We propose to obtain UBVI images of the MOA-2002-BLG-33 microlensing event source star at two different epochs with the ACS/HRC instrument. Each visit will consist of two orbits with the first orbit devoted to F330W observations and the second orbit used for F435W, F555W and F814W observations. All observations will be box-dithered for maximum resolution, and all images at each dither position will be cosmic ray split except for the F814W images which have exposures on only 40 seconds. Real Time Justification ----------------------- The proposed observations are time critical since the MOA-2002-BLG-33 lensing event will be over within a few months, and observations during the event are necessary for a high confidence level determination the amount of blending. If the proposed observations are taken within 5 weeks of the submission of this proposal, the source will still by magnified by at least 0.5 magnitudes, but if we wait until the start of Cycle 12, the magnification will only be about 1 mill-magnitude which would not be detectable. This proposal was obviously not possible in Cycle 11 because the MOA-2002-BLG-33 event was not discovered until June, 2002. A TOO proposal was not practical because it was not possible to estimate the probability of such an event prior to this bulge season, since the abundance of planets orbiting stars in the inner galaxy is not known. Calibration Justification ------------------------- Additional Comments ------------------- We would like the first epoch to be scheduled as soon as possible - without a major disruption of the HST scheduling process. The target star is fading in brightness, and we prefer first epoch images with the target as bright as possible. ------------------------------------------------------------------------------------ 9691( 4) - 03/27/03 12:43 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 MOA-2002- STAR, BULGE, G V-IV RA=17H 58M 24.6S +/- 2", DEC=- J2000 V = 20.0+/-0.5 BLG-33 29D 6' 11.3" +/- 2" V-I = 1.5+/-0.6 Coordinate Source: IMAGE_TIED_TO_GSC_FRAME 9691( 4) - 03/27/03 12:43 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-HRC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.150 Coordinate_Frame POS-TARG Pattern_Orient 19.89 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 9691( 4) - 03/27/03 12:43 - [ 5] Visit: 01 Visit Priority: Visit Requirements: ORIENT 90D TO 90D BEFORE 22-Aug-2002 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 MOA-2002-BL ACS/HR ACCUM HRC F330W 1 540 S PATTERN 1 10 G-33 C ------------------------------------------------------------------------------------------------------------------------------------ 20 MOA-2002-BL ACS/HR ACCUM HRC F435W 1 200 S PATTERN 1 20 G-33 C ------------------------------------------------------------------------------------------------------------------------------------ 30 MOA-2002-BL ACS/HR ACCUM HRC F555W 1 60 S PATTERN 1 30 G-33 C ------------------------------------------------------------------------------------------------------------------------------------ 40 MOA-2002-BL ACS/HR ACCUM HRC F814W CR-SPLIT=NO 1 40 S PATTERN 1 40 G-33 C ------------------------------------------------------------------------------------------------------------------------------------ 9691( 4) - 03/27/03 12:43 - [ 6] Visit: 02 Visit Priority: Visit Requirements: ORIENT 90D TO 90D BETWEEN 15-Oct-2002 AND 01-Jan-2003 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 MOA-2002-BL ACS/HR ACCUM HRC F330W 1 540 S PATTERN 1 10 G-33 C ------------------------------------------------------------------------------------------------------------------------------------ 20 MOA-2002-BL ACS/HR ACCUM HRC F435W 1 200 S PATTERN 1 20 G-33 C ------------------------------------------------------------------------------------------------------------------------------------ 30 MOA-2002-BL ACS/HR ACCUM HRC F555W 1 60 S PATTERN 1 30 G-33 C ------------------------------------------------------------------------------------------------------------------------------------ 40 MOA-2002-BL ACS/HR ACCUM HRC F814W CR-SPLIT=NO 1 40 S PATTERN 1 40 G-33 C ------------------------------------------------------------------------------------------------------------------------------------ 9691( 4) - 03/27/03 12:43 - [ 7] Summary Form for Proposal 9691 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures HRC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/HRC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO/DD ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 90D TO 90D BEFORE 22-Aug-2002 PATTERN 1 10 PATTERN 1 20 PATTERN 1 30 PATTERN 1 40 ORIENT 90D TO 90D BETWEEN 15-Oct-2002 AND 01-Jan-2003 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F330W F435W F555W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names MOA-2002-BLG-33 ------------------------------------------------------------------------------------------------------------------------------------