14726( 8) - 02-Aug-2017 18:02:26 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14726 Version: 8 Check-in Time: 02-Aug-2017 18:02:26 STScI Edit Number: 7 Title Ruprecht 106: Too small to succeed? ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Aaron L. Dotter Harvard University Y CoI: Dr. Anna Fabiola Marino Australian National University N CoI: Dr. Antonino Paolo Milone Australian National University N CoI: Dr. Ata Sarajedini Florida Atlantic University N CoI: Prof. Charlie Conroy Harvard University N ------------------------------------------------------------------------------------ Abstract Photometric studies with HST have completely changed our understanding of globular clusters (GCs), to the point where features that were once considered anomalous (light-element abundance variations, multiple populations) are now part of the definition of the term 'globular cluster'. With this proposal, we seek to establish some minimum requirements for the formation of multiple stellar populations in GCs. We will apply the unique UV and blue imaging capabilities of the Wide Field Camera 3 UVIS channel to search for multiple stellar sequences, or lack thereof, in the CMD of the peculiar GC Ruprecht 106. Ruprecht 106 is exceptional among the Galactic GC population in its primordial chemical composition, low mass, and (likely) extra-Galactic origin. The limited abundance information available from spectroscopy indicates a low oxygen abudance (average [O/Fe] ~ 0 at [Fe/H] ~ -1.5) with no significant star-to-star scatter in the light elements. Light element abundance variations are one of the fundamental signatures of multiple stellar populations in GCs; the other is the presence of multiple stellar sequences in the CMD. The first line of inquiry, spectroscopy, suggests Ruprecht 106 may be a true simple stellar population. This proposal addresses the second line of inquiry, the photometric signature, which has never before been attempted. The unrivaled resolution and sensitivity of the Hubble Space Telescope will allow us to discover whether the CMD of Ruprecht 106 reveals multiple and/or broadened stellar sequences and, thus, hosts multiple stellar populations -- or not. ------------------------------------------------------------------------------------ Observations Description ------------------------ The observing program is designed to image Ruprecht 106 in two WFC3/UVIS filters, F336W and F438W. These data will be combined with existing ACS/WFC data in F814W to make the "CUBI" index (F336W-F438W)-(F438W-F814W), which is sensitive to light-element abudance variations. There are 4 1-orbit visits, each separated by approximately 90-degree change in the orientation angle. This allows for maximum sampling of the PSF. ------------------------------------------------------------------------------------ 14726( 8) - 02-Aug-2017 18:02:26 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 RUPRECHT-106 STELLAR CLUSTER, RA=12H38M40.2000S, J2000 V = 10.9 GLOBULAR CLUSTER DEC=-51D09'1.00" Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 14726( 8) - 02-Aug-2017 18:02:26 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 14726( 8) - 02-Aug-2017 18:02:26 - [ 4] Visit: 01 Visit Requirements: 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 RUPRECHT-10 WFC3/UVI ACCUM UVIS-CENT F336W FLASH=9 1 1100 S PATTERN 2 1 6 S ER (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RUPRECHT-10 WFC3/UVI ACCUM UVIS-CENT F438W FLASH=7 1 571 S (571 6 S ER S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ RUPRECHT-106 1 WFC3/UVI ACCUM UVIS-CEN F336W 1 none none none 1 N/A S TER RUPRECHT-106 1 WFC3/UVI ACCUM UVIS-CEN F336W 2 none none none 1 N/A S TER RUPRECHT-106 2 WFC3/UVI ACCUM UVIS-CEN F438W none none none none 1 N/A S TER 14726( 8) - 02-Aug-2017 18:02:26 - [ 5] Visit: 02 Visit Requirements: ORIENT -90D TO -85D FROM 01 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 RUPRECHT-10 WFC3/UVI ACCUM UVIS-CENT F336W FLASH=9 1 1100 S PATTERN 2 1 6 S ER (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RUPRECHT-10 WFC3/UVI ACCUM UVIS-CENT F438W FLASH=7 1 571 S (571 6 S ER S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ RUPRECHT-106 1 WFC3/UVI ACCUM UVIS-CEN F336W 1 none none none 1 N/A S TER RUPRECHT-106 1 WFC3/UVI ACCUM UVIS-CEN F336W 2 none none none 1 N/A S TER RUPRECHT-106 2 WFC3/UVI ACCUM UVIS-CEN F438W none none none none 1 N/A S TER 14726( 8) - 02-Aug-2017 18:02:26 - [ 6] Visit: 03 Visit Requirements: ORIENT 175D TO 180D FROM 02 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 RUPRECHT-10 WFC3/UVI ACCUM UVIS-CENT F336W FLASH=9 1 1100 S PATTERN 2 1 6 S ER (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RUPRECHT-10 WFC3/UVI ACCUM UVIS-CENT F438W FLASH=7 1 571 S (571 6 S ER S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ RUPRECHT-106 1 WFC3/UVI ACCUM UVIS-CEN F336W 1 none none none 1 N/A S TER RUPRECHT-106 1 WFC3/UVI ACCUM UVIS-CEN F336W 2 none none none 1 N/A S TER RUPRECHT-106 2 WFC3/UVI ACCUM UVIS-CEN F438W none none none none 1 N/A S TER 14726( 8) - 02-Aug-2017 18:02:26 - [ 7] Visit: 04 Visit Requirements: ORIENT 170D TO 176 D 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 RUPRECHT-10 WFC3/UVI ACCUM UVIS-CENT F336W FLASH=9 1 1100 S PATTERN 2 1 6 S ER (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RUPRECHT-10 WFC3/UVI ACCUM UVIS-CENT F438W FLASH=7 1 571 S (571 6 S ER S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ RUPRECHT-106 1 WFC3/UVI ACCUM UVIS-CEN F336W 1 none none none 1 N/A S TER RUPRECHT-106 1 WFC3/UVI ACCUM UVIS-CEN F336W 2 none none none 1 N/A S TER RUPRECHT-106 2 WFC3/UVI ACCUM UVIS-CEN F438W none none none none 1 N/A S TER 14726( 8) - 02-Aug-2017 18:02:26 - [ 8] Visit: 05 Visit Requirements: ORIENT 170D TO 176 D 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 RUPRECHT-10 WFC3/UVI ACCUM UVIS-CENT F336W FLASH=9 1 1100 S POS TARG 0.099, 0.106; 6 S ER (2200 S) PATTERN 2 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 RUPRECHT-10 WFC3/UVI ACCUM UVIS-CENT F438W FLASH=7 1 571 S (571 POS TARG 0.099, 0.106 6 S ER S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ RUPRECHT-106 1 WFC3/UVI ACCUM UVIS-CEN F336W 1 none none none 1 N/A S TER RUPRECHT-106 1 WFC3/UVI ACCUM UVIS-CEN F336W 2 none none none 1 N/A S TER RUPRECHT-106 2 WFC3/UVI ACCUM UVIS-CEN F438W none none none none 1 N/A S TER 14726( 8) - 02-Aug-2017 18:02:26 - [ 9] Summary Form for Proposal 14726 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS-CENTER ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=7, FLASH=9 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT -90D TO -85D FROM 01, ORIENT 170D TO 176 D, ORIENT 175D TO 180D FROM 02, PATTERN 2 1, POS TARG 0.099, 0.106 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F336W, F438W ------------------------------------------------------------------------------------------------------------------------------------ Target Names RUPRECHT-106 ------------------------------------------------------------------------------------------------------------------------------------