10774( 6) - 02/17/06 16:12 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 10774 Version: 6 Check-in Time: 17-Feb-2006 21:11:59 Title Confirming the Discovery of Two New Satellites of Pluto ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance GO/DD 14 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Harold A. Weaver The Johns Hopkins University Applied Physics Laboratory CoI: Dr. S. Alan Stern Southwest Research Institute N CoI: Dr. John R. Spencer Southwest Research Institute N CoI: Dr. Marc W. Buie Lowell Observatory N CoI: Dr. Eliot Young Southwest Research Institute N CoI: Dr. Leslie A. Young Southwest Research Institute N CoI: Dr. Andrew Steffl Southwest Research Institute N CoI: Mr. Max Mutchler Space Telescope Science Institute Y CoI: Dr. William J. Merline Southwest Research Institute N ------------------------------------------------------------------------------------ Abstract We detected two new objects ~2 arcsec from Pluto during our recent deep search for companions using the ACS / WFC mode (HST GO program 10427). Either these objects are newly discovered satellites of Pluto, or they are previously undiscovered Plutino KBOs that happened to be located along the line-of-sight to Pluto. The ramifications are enormous for our understanding of the origin and evolution of the Pluto-Charon system, and for our understanding of KBO satellite formation in general, if these new objects are satellites of Pluto. Thus, we request two orbits of HST observing time as soon as possible, to confirm that these newly discovered objects are truly satellites of Pluto. ------------------------------------------------------------------------------------ 10774( 6) - 02/17/06 16:12 - [ 2] Observations Description ------------------------ These observations will be very similar to our ACS / WFC observations of Pluto (HST GO program 10427), where we first discovered the new satellites S/2005 P 1 and S/2005 P 2. However, since these objects were detected within a few arcseconds of Pluto-Charon, we will now utilize the ACS / HRC instead. The HRC field-of-view (~29x26 arcseconds) is much smaller than the WFC, but still easily large enough to image the entire system, and at higher resolution. Although the orbits of P1 and P2 are not definitively determined yet, we believe they are Charon-like and essentially circular, so they should never be more than a few arcseconds from Pluto. We employ a sub-pixel dither box pattern, both to avoid bad detector pixels and to improve the spatial sampling as much as possible. At each dither point we take one long exposure, where Pluto-Charon will be saturated (with some bleeding along the CCD columns), and where we expect to detect P1 and P2. We also take at least one short (1 second) exposure at each dither point, where P1 and P2 will not be detected, but Pluto and Charon will be unsaturated and provide additional positional information which will aid in the registration of the images. The short exposures would also reveal (and allow us to correct for) any drift in the moving target tracking, which we otherwise expect to be accurate to within a fraction of a pixel (i.e. good enough to faithfully execute a sub-pixel dither pattern). Then we repeat these observations in an identical visit, about 15 days days later (which is roughly half of the orbital period of both satellites), to confirm the orbital motion of the objects. We expect these observations to confirm the status of P1 and P2 as satellites of Pluto, and further constrain their orbital elements. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- We would like the first epoch (orbit) of this program to execute as soon as possible after Pluto becomes observable again by HST (in 2 gyro mode) around 15 February 2006. Note as of 17 Feb 2006: After analyzing the first visit, which completely verified the existence and orbits of P1 and P2, our team was given permission by the STScI Director (Matt Mountain) to modify visit 2 to incorporate another filter (we chose B-band F435W). ------------------------------------------------------------------------------------ 10774( 6) - 02/17/06 16:12 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: PLUTO ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET Pluto ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=PLUTO | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 14.0+/-0.1 | | ------------------------------------------------------------------------------------------------------------------------------------ 10774( 6) - 02/17/06 16:12 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-HRC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 1.9 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 5.85 Angle_Between_Sides Center_Pattern NO Pattern_Comments: This shift spans the HRC occulting finger, to ensure that neither satellite P1 and P2 can be hidden behind the finger in all 4 exposures. ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type ACS-HRC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.15 Line_Spacing 0.098 Coordinate_Frame POS-TARG Pattern_Orient 19.89 Angle_Between_Sides 63.5 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type ACS-HRC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.198 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 44.28 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 10774( 6) - 02/17/06 16:12 - [ 5] Visit: 01 Visit Priority: Visit Requirements: BETWEEN 13-FEB-2006:00:00:00 AND 20-FEB-2006:00:00:00 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 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 1 S SEQ 1-5 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 475 S ------------------------------------------------------------------------------------------------------------------------------------ 3 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 1 S ------------------------------------------------------------------------------------------------------------------------------------ 4 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 475 S POS TARG 0.142, 0.052 ------------------------------------------------------------------------------------------------------------------------------------ 5 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 1 S POS TARG 0.142, 0.052 ------------------------------------------------------------------------------------------------------------------------------------ 6 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 1 S POS TARG 0.071, 0.119; SEQ 6-10 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 7 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 475 S POS TARG 0.071, 0.119 ------------------------------------------------------------------------------------------------------------------------------------ 8 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 1 S POS TARG -0.071, 0.067 ------------------------------------------------------------------------------------------------------------------------------------ 9 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 475 S POS TARG -0.071, 0.067 ------------------------------------------------------------------------------------------------------------------------------------ 10 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 1 S POS TARG -0.071, 0.067 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ PLUTO 1 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 2 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 3 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 4 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 5 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 6 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 7 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 8 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 9 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 10 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A 10774( 6) - 02/17/06 16:12 - [ 6] Visit: 02 Visit Priority: Visit Requirements: SAME ORIENT AS 01; AFTER 01 BY 15 D TO 15.4 D; BETWEEN 27-FEB-2006:00:00:00 AND 06-MAR-2006:00:00:00 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 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 145 S SEQ 1-8 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 PLUTO ACS/HRC ACCUM HRC-FIX F435W CR-SPLIT=NO 1 475 S ------------------------------------------------------------------------------------------------------------------------------------ 3 PLUTO ACS/HRC ACCUM HRC-FIX F435W CR-SPLIT=NO 1 3 S ------------------------------------------------------------------------------------------------------------------------------------ 4 PLUTO ACS/HRC ACCUM HRC-FIX F435W CR-SPLIT=NO 1 475 S POS TARG 0.142, 0.139 ------------------------------------------------------------------------------------------------------------------------------------ 5 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 145 S POS TARG 0.142, 0.139 ------------------------------------------------------------------------------------------------------------------------------------ 6 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 1 S POS TARG 0.284, 0.278 ------------------------------------------------------------------------------------------------------------------------------------ 7 PLUTO ACS/HRC ACCUM HRC-FIX F606W CR-SPLIT=NO 1 145 S POS TARG 0.284, 0.278 ------------------------------------------------------------------------------------------------------------------------------------ 8 PLUTO ACS/HRC ACCUM HRC-FIX F435W CR-SPLIT=NO 1 475 S POS TARG 0.284, 0.278 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ PLUTO 1 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 2 ACS/HRC ACCUM HRC-FIX F435W none none none none 1 N/A PLUTO 3 ACS/HRC ACCUM HRC-FIX F435W none none none none 1 N/A PLUTO 4 ACS/HRC ACCUM HRC-FIX F435W none none none none 1 N/A PLUTO 5 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 6 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 7 ACS/HRC ACCUM HRC-FIX F606W none none none none 1 N/A PLUTO 8 ACS/HRC ACCUM HRC-FIX F435W none none none none 1 N/A 10774( 6) - 02/17/06 16:12 - [ 7] Summary Form for Proposal 10774 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures HRC-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/HRC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 13-FEB-2006 00 00 00 AND 20-FEB-2006 00 00 00; SEQ 1-5 NON-INT; POS TARG 0.142, 0.052; POS TARG 0.071, 0.119; SEQ 6-10 NON-INT; POS TARG -0.071, 0.067; SAME ORIENT AS 01; AFTER 01 BY 15 D TO 15.4 D; BETWEEN 27-FEB-2006 00 00 00 AND 06-MAR-2006 00 00 00; SEQ 1-8 NON-INT; POS TARG 0.142, 0.139; POS TARG 0.284, 0.278; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F606W F435W ------------------------------------------------------------------------------------------------------------------------------------ Target Names PLUTO ------------------------------------------------------------------------------------------------------------------------------------