Proposal_Information ! Section 4 Title: PC Astrometry of the Brown Dwarf Candidate PPL 15 Proposal_Category: GO Scientific_Category: COOL STARS Cycle: 6 Investigators PI_name: D. Jack MacConnell PI_Institution: Computer Sciences Corporation CoI_Name: Edward Rosenthal CoI_Institution: Center for Astrophysics Contact: ! Y or N (designate at most one contact) CoI_Name: Wm. van Altena CoI_Institution: Yale University Observatory Contact: ! Y or N (designate at most one contact) CoI_Name: John Stauffer CoI_Institution: Center for Astrophysics Contact: ! Y or N (designate at most one contact) CoI_Name: Geoffrey Marcy CoI_Institution: San Francisco State University Contact: ! Y or N (designate at most one contact) CoI_Name: Gibor Basri CoI_Institution: University of California - Berkeley Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) We plan to obtain deep, far red PC images of the field around the brown dwarf candidate, PPl 15, in the Pleiades. This low-mass object is the only brown dwarf candidate to date to show Li I in its spectrum thus at least requiring a mass of < 0.1 Msun. Its radial velocity matches that of more massive stars in the Pleiades, but nothing is known of its proper motion which accounts for two of three velocity vectors. Its membership is probable but will remain uncertain until the proper motion is determined. In addition to determining the proper motion, we expect to determine its parallax which will fix its luminosity and definitively answer the question of membership. The PC frames will also be useful to search for any anomalies in the image structure of PPl 15. Questions ! Free format text (please update) Observing_Description: We will use the F814W filter which is efficient and a good compromise for the energy distribution of PPl 15 and the unknown reference stars. An exposure of 300s will give a S/N of 55 on PPl 15 without saturating the central pixel. Because a good frame of reference stars is paramount to doing good astrometry, we wish to use the first orbit to take one or more test exposures to permit us to decide what combination of offset and orientation will provide the best reference frame. It is likely that the test exposures can be used in the final astrometric solution. We will then image at the best position with PPl 15 offset from the PC center as little as possible during four orbits separated by about six- month intervals when the parallax factor is near a maximum. The maxima are 21 Aug. and 20 Feb. With the 5-minute exposure times, we will be able to obtain four exposures per 53-minute visibility period after the GS acquisition and overheads, and we will sub- pixel dither between them to improve the spatial resolution and S/N. We will use spatial scans to dither rather than POS TARGs which are less efficient. The multiple images will also be useful for cosmic-ray rejection. Real_Time_Justification: The visits are to be linked by six-month intervals and will be loosely time-critical to the level of a few weeks. Specific orients are expected. None. There are no coordinated observations necessary or planned. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number:1 Target_Name:PPL-15 Alternate_Names: Description:STAR,BROWN DWARF Position:RA=3H 48M 4.5S +/- 0.1S, ! Most common specification format is DEC=+23D 39' 33" +/- 1" ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox:J2000.0 RV_or_Z:V=+5.6 RA_PM:+0.0015 ! Units are seconds of time per year Dec_PM:-.045 ! Units are seconds of arc per year Epoch:1989.5 Annual_Parallax:0.008 Flux:V=22.46,V-I=4.64 ! Include at least V and B-V Comments:NO VALUE OF B-V AVAILABLE Target_Number:2 Target_Name:REV-PPL-15 Alternate_Names: Description:STAR,BROWN DWARF Position:RA=57.01726D +/- 0.000001851D, ! Most common specification format is DEC=+23.66215D +/- 0.000278D ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox:J2000.0 Flux:V=22.46,V-I=4.64 ! Include at least V and B-V Comments:NO VALUE OF B-V AVAILABLE, new coordinates from PI on 7/23/96. Target_Number:3 Target_Name:PPL-15-NEW Alternate_Names: Description:STAR,BROWN DWARF Position:RA=57.01948D +/- 0.000001851D, ! Most common specification format is DEC=+23.66515D +/- 0.000278D ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox:J2000.0 RV_or_Z:V=+5.6 RA_PM:+0.0015 ! Units are seconds of time per year Dec_PM:-.045 ! Units are seconds of arc per year Epoch:1989.5 Annual_Parallax:0.008 Flux:V=22.46,V-I=4.64 ! Include at least V and B-V Comments:NO VALUE OF B-V AVAILABLE Scan_Data ! Appendix B Scan_Number:1 FGS_Scan: Cont_or_Dwell:D Dwell_Points:2 Dwell_Secs:1.0 Scan_Width:10.0 Scan_Length:10.0 Sides_Angle:90 Number_Lines:2 Scan_Rate: First_Line_PA:90 Scan_Frame:CEL Length_Offset: Width_Offset: ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number:1 Visit_Requirements: ! Section 7.1 ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling PCS MODE F BEFORE 12-JUN-1996 On_Hold_Comments: Visit_Comments:This is a test visit to decide on final values of position and ORIENT of tgt. in PC1 so as to maximize number of ref. stars and choose ones not near edges. Exposure_Number:1 ! Section 6.5 Target_Name:PPL-15 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F814W Wavelength: Optional_Parameters:CR-SPLIT=NO,SCAN-READ=ALL Number_of_Iterations:1 Time_Per_Exposure:400S Special_Requirements: SPATIAL SCAN 1 Visit_Number:2 Visit_Requirements: ! Section 7.1 PCS MODE F ON HOLD FOR 1 BETWEEN 2-MAR-1997 AND 17-MAR-1997 ORIENT 70.58D TO 80.58D On_Hold_Comments:Waiting for analysis of 1st Visit Visit_Comments:Desired pos. and ORIENT will be entered for Visit 2 after examining field taken in Visit 1. New coordinates entered and new orientation. Exposure_Number:2 ! Section 6.5 Target_Name:REV-PPL-15 Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F814W Wavelength: Optional_Parameters:CR-SPLIT=NO,DITHER-TYPE=LINE Number_of_Iterations:2 Time_Per_Exposure:400S Special_Requirements: ! Section 7.2 Comments:Because of requirements for accurate astrometry, Vis. 1/2 must be at same pos. and orient. and close to 1 yr. apart. Vis. 3/4 must be v. close to 6 months after them and oriented 180 deg. from them. Visit_Number:3 Visit_Requirements: ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling PCS MODE F ORIENT 250.58D to 260.58D BETWEEN 10-AUG-1997 AND 10-SEP-1997 Visit_Comments: Exposure_Number:3 ! Section 6.5 Target_Name:PPL-15-NEW Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F814W Wavelength: Optional_Parameters:CR-SPLIT=NO,DITHER-TYPE=LINE Number_of_Iterations:2 Time_Per_Exposure:400S Special_Requirements: ! Section 7.2 ! Uncomment or copy exposure level special requirements needed Comments:The 'between' on V. 3 is for the max. pi factor but is during SM2 - ok if SM2 is delayed. If not, must sched. as late as possible before SM2. Visit_Number:4 Visit_Requirements: ! Section 7.1 ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling PCS MODE F ORIENT 250.58D TO 260.58D BETWEEN 10-AUG-1998 AND 10-SEP-1998 Visit_Comments:Use same GS as Visit 3 Exposure_Number:4 ! Section 6.5 Target_Name:PPL-15-NEW Config:WFPC2 Opmode:IMAGE Aperture:PC1-FIX Sp_Element:F814W Wavelength: Optional_Parameters:CR-SPLIT=NO,DITHER-TYPE=LINE Number_of_Iterations:2 Time_Per_Exposure:400S Special_Requirements: ! Section 7.2 ! Uncomment or copy exposure level special requirements needed Comments: Data_Distribution ! Defaults indicated; change if desired Medium: 8MM ! 8MM or 6250BPI or 1600BPI Blocking_Factor: 10 ! 10 or 1 ! Only astronomers with very old 9- ! track tape drives should consider ! a blocking factor of 1 Ship_To: PI_Address ! STSCI or PI_Address or ! PI Address from Phase I is: ! ! Space Telescope Science Institute ! 3700 San Martin Drive ! Baltimore ! 21218 ! ! Ship_Via: UPS ! UPS (2-day) or OVERNIGHT ! Overnight shipping done at PI expense ! Let us know what you think of this template and software! ! Please send a list of your likes and dislikes to your Program Coordinator __Diagnostic-Sum-Section__ Software-Version (Controller= 6.0) Preprocessor (Errors= 0 Fatal-Errors= 0 ) Validation (Errors= 0 Fatal-Errors= 0 ) Transformation (Errors= 0 Fatal-Errors= 0 ) CASM (Errors= 4 Fatal-Errors= 0 ) __User-Comments__