8563( 2) - 03/02/00 11:44 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8563 Version: 2 Check-in Date: 02-Mar-2000 11:43:36 1.Proposal Title: Determining the Duplicity of Nearby T Dwarfs (Methane Brown Dwarfs) ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 9 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: J. Kirkpatrick California Institute of Technology CoI: Mr. Adam Burgasser California Institute of Technology N CoI: Dr. Neill Reid University of Pennsylvania N CoI: Dr. James Liebert University of Arizona N CoI: Dr. John Gizis Infrared Processing and Analysis Center N ------------------------------------------------------------------------------------ 5. Abstract Knowing the binary fraction of T-type dwarfs (methane brown dwarfs) is crucial to accurate determinations of the T-dwarf space density and mass function, especially since equal- magnitude binaries can introduce significant biases in photometric distance estimates. Because a recent study of slightly hotter L dwarfs indicates that 30 percent of those systems form as equal-magnitude binaries, we believe that T dwarfs may show a similar tendency to form equal-mass pairs. Characterization of the T-dwarf multiplicity fraction is necessary if properties of the first few discoveries are to be adequately applied to larger samples uncovered later. We propose to image ten newly discovered T dwarfs using the incomparable resolution of WFPC2, where colors from the F814W and F1042M filters will provide discrimination of background sources. This imaging program will not only be able to split close binaries, but will also be capable of detecting wider companions up to four magnitudes fainter than the T dwarf primary. This will enable us to probe to temperatures around 500K, much cooler than any brown dwarf previously identified and squarely in the regime occupied by young, high-mass planets. ------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 2] Observations Description ------------------------ The complete observation sequence of each target will require 2 orbits (except for 2MASSW J1237+65, which requires only one CVZ orbit). Each orbit will consist of the target being roughly centered on the PC chip and a 2400-sec exposure (CR- split into two equal-time pieces) taken in F814W for one orbit and F1042M for the other. The 2400-sec exposure time will fill the entire orbit after overheads for guide star (re-)acquisitions, CR-splitting, and WFPC2 ``efficiency'' are considered. Typical magnitudes for the target T dwarfs are m_F814W = 23.2 and m_F1042M = 19.4, and our 2400-sec exposures will yield SNR=3 detection limits of m_F814W = 27.3 and m_F1042M = 22.9, allowing us to search for ~500K objects around these T dwarf primaries. We request that these data be given the usual 12-month period for proprietary rights. Real Time Justification ----------------------- None. Calibration Justification ------------------------- None. Additional Comments ------------------- None. ------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 2MASSW-J0559 STAR, Brown Dwarf RA=05H 59M 19.14S +/- 0.05S, J2000 J = 13.83+/-0.03 -14 DEC=-14D 04' 48.93" +/- 0.5" TYPE=T R-J = 9.2+/-1.0 2 2MASSW- STAR, Brown Dwarf RA=09H 37M 34.79S +/- 0.05S, J2000 J = 14.65+/-0.04 J0937+29 DEC=+29D 31' 42.59" +/- 0.5" TYPE=T R-J = 9.2+/-1.0 3 2MASSI- STAR, Brown Dwarf RA=10H 47M 53.88S +/- 0.05S, J2000 J = 15.82+/-0.06 J1047+21 DEC=+21D 24' 23.22" +/- 0.5" TYPE=T R-J = 9.2+/-1.0 4 2MASSW-J1217 STAR, Brown Dwarf RA=12H 17M 11.09S +/- 0.05S, J2000 J = 15.85+/-0.07 -03 DEC=-03D 11' 13.08" +/- 0.5" TYPE=T R-J = 9.2+/-1.0 5 2MASSW-J1225 STAR, Brown Dwarf RA=12H 25M 54.32S +/- 0.05S, J2000 J = 15.23+/-0.05 -27 DEC=-27D 39' 46.58" +/- 0.5" TYPE=T R-J = 9.2+/-1.0 6 2MASSW- STAR, Brown Dwarf RA=12H 37M 39.16S +/- 0.05S, J2000 J = 15.80+/-0.08 J1237+65 DEC=+65D 26' 14.58" +/- 0.5" TYPE=T R-J = 9.2+/-1.0 7 GL-570D STAR, Brown Dwarf RA=14H 57M 14.96S +/- 0.05S, J2000 J = 15.33+/-0.05 DEC=-21D 21' 47.79" +/- 0.5" TYPE=T R-J = 9.2+/-1.0 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B1998.038 0.0740 -1.725 0.169 8 2MASSW-J1534 STAR, Brown Dwarf RA=15H 34M 49.83S +/- 0.05S, J2000 J = 14.89+/-0.04 -29 DEC=-29D 52' 27.36" +/- 0.5" TYPE=T R-J = 9.2+/-1.0 9 2MASSW-J1546 STAR, Brown Dwarf RA=15H 46M 27.18S +/- 0.05S, J2000 J = 15.60+/-0.05 -33 DEC=-33D 25' 11.36" +/- 0.5" TYPE=T R-J = 9.2+/-1.0 10 2MASSW-J2356 STAR, Brown Dwarf RA=23H 56M 54.77S +/- 0.05S, J2000 J = 15.80+/-0.06 -15 DEC=-15D 53' 10.66" +/- 0.5" TYPE=T R-J = 9.2+/-1.0 8563( 2) - 03/02/00 11:44 - [ 4] Visit: 01 Visit Priority: 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 2MASSW-J055 WFPC2 IMAGE PC1 F814W CR-SPLIT=0.5 1 2400 S 9-14 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSW-J055 WFPC2 IMAGE PC1 F1042M CR-SPLIT=0.5 1 2600 S 9-14 ------------------------------------------------------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 5] Visit: 02 Visit Priority: 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 2MASSW-J093 WFPC2 IMAGE PC1 F814W CR-SPLIT=0.5 1 2600 S 7+29 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSW-J093 WFPC2 IMAGE PC1 F1042M CR-SPLIT=0.5 1 2600 S 7+29 ------------------------------------------------------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 6] Visit: 03 Visit Priority: 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 2MASSI-J104 WFPC2 IMAGE PC1 F814W CR-SPLIT=0.5 1 2400 S 7+21 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J104 WFPC2 IMAGE PC1 F1042M CR-SPLIT=0.5 1 2600 S 7+21 ------------------------------------------------------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 7] Visit: 04 Visit Priority: 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 2MASSW-J121 WFPC2 IMAGE PC1 F814W CR-SPLIT=0.5 1 2400 S 7-03 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSW-J121 WFPC2 IMAGE PC1 F1042M CR-SPLIT=0.5 1 2600 S 7-03 ------------------------------------------------------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 8] Visit: 05 Visit Priority: 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 2MASSW-J122 WFPC2 IMAGE PC1 F814W CR-SPLIT=0.5 1 2600 S 5-27 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSW-J122 WFPC2 IMAGE PC1 F1042M CR-SPLIT=0.5 1 2600 S 5-27 ------------------------------------------------------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 9] Visit: 06 Visit Priority: Visit Requirements: CVZ 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 2MASSW-J123 WFPC2 IMAGE PC1 F814W CR-SPLIT=0.5 1 2000 S 7+65 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSW-J123 WFPC2 IMAGE PC1 F1042M CR-SPLIT=0.5 1 2400 S 7+65 ------------------------------------------------------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 10] Visit: 07 Visit Priority: 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 GL-570D WFPC2 IMAGE PC1 F814W CR-SPLIT=0.5 1 2400 S ------------------------------------------------------------------------------------------------------------------------------------ 2 GL-570D WFPC2 IMAGE PC1 F1042M CR-SPLIT=0.5 1 2600 S ------------------------------------------------------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 11] Visit: 08 Visit Priority: 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 2MASSW-J153 WFPC2 IMAGE PC1 F814W CR-SPLIT=0.5 1 2600 S 4-29 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSW-J153 WFPC2 IMAGE PC1 F1042M CR-SPLIT=0.5 1 2600 S 4-29 ------------------------------------------------------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 12] Visit: 09 Visit Priority: 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 2MASSW-J154 WFPC2 IMAGE PC1 F814W CR-SPLIT=0.5 1 2600 S 6-33 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSW-J154 WFPC2 IMAGE PC1 F1042M CR-SPLIT=0.5 1 2600 S 6-33 ------------------------------------------------------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 13] Visit: 10 Visit Priority: 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 2MASSW-J235 WFPC2 IMAGE PC1 F814W CR-SPLIT=0.5 1 2400 S 6-15 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSW-J235 WFPC2 IMAGE PC1 F1042M CR-SPLIT=0.5 1 2600 S 6-15 ------------------------------------------------------------------------------------------------------------------------------------ 8563( 2) - 03/02/00 11:44 - [ 14] Summary Form for Proposal 8563 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=0.5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W F1042M ------------------------------------------------------------------------------------------------------------------------------------ Target Names 2MASSW-J0559-14 2MASSW-J0937+29 2MASSI-J1047+21 2MASSW-J1217-03 2MASSW-J1225-27 2MASSW-J1237+65 GL-570D 2MASSW-J1534-29 2MASSW-J1546-33 2MASSW-J2356-15 ------------------------------------------------------------------------------------------------------------------------------------