15297( 3) - 14-Jul-2017 17:44:22 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15297 Version: 3 Check-in Time: 14-Jul-2017 17:44:22 STScI Edit Number: 0 Title Measuring the structure of Fomalhaut's dusty debris belt via a fortuitous stellar occultation ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Tiffany Meshkat California Institute of Technology Y CoI: Dr. Matthew Kenworthy Universiteit Leiden N CoI: Dr. Benne Willem Holwerda University of Louisville Research N Foundation, Inc. CoI: Dr. Paul George Kalas University of California - Berkeley N CoI: Dr. Kevin France University of Colorado at Boulder N ------------------------------------------------------------------------------------ Abstract Fomalhaut, a young nearby A4V star, is surrounded by an inclined dust debris belt, directly imaged in optical scattered light with HST. The proper motion and parallax of Fomalhaut will move this belt across an 18.5 magnitude background star in the next decade. This presents a unique and fortuitous opportunity to probe the dust structure and confirm disk dynamical theory to unprecedented resolution. In Cycle-21 we obtained HST/STIS spectra of the background star during the diffuse phase of the debris disk occultation. We propose obtaining HST/STIS spectra during the thick (Cycle-24 to 26), and pristine (~2021 with JWST) phases of occultation as the debris disk moves across the target background star. This is a rare opportunity to measure - for the first time - the dust optical depth structure in a known planet-forming system, providing a valuable constraint on current planet formation theories. This experiment will act as a pathfinder for this type of science for future observations with JWST and future ELTs. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will use STIS] in Cycle-24, 25, and 26 to observe a 18.5 magnitude background star as it passes behind the Fomalhaut debris disk. We will obtain a quick (2 s) image with STIS 50CORON MIRVIS for preimaging photometry of the background star. In the same orbit, we will switch to STIS G750L for the remaining time (~31 minutes). ------------------------------------------------------------------------------------ 15297( 3) - 14-Jul-2017 17:44:22 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 FOMALHAUT-BA STAR, G V-IV RA-OFF=0.550S, DEC-OFF=-14.12", J2000 V = 18.5 +/- 0.5 CKGROUND-SOU FROM 2 RCE-OFF Comments: The offset of this target may be updated, depending on when the observation is scheduled. ------------------------------------------------------------------------------------------------------------------------------------ 2 FOMALHAUT STAR, A0-A3 V-IV RA=22H57M39.0463S +/- 0.1", J2000 V = 1.16 DEC=-29D37'20.05" +/- 0.1" Reference Frame: ICRS Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.0 0.0255 -0.16466999999999998 0.13008 ------------------------------------------------------------------------------------------------------------------------------------ 15297( 3) - 14-Jul-2017 17:44:22 - [ 3] Visit: 01 (Orbit 2: Cycle 25) Visit Requirements: ORIENT 217D TO 281 D On Hold Comments: Additional Comments: First we will acquire Fomalhaut and then offset to the 18.5 magnitude background star. 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 FOMALHAUT STIS/CCD ACQ F25ND5 MIRROR 1 0.5 S (0.5 S) Comments: Acquire Fomalhaut ------------------------------------------------------------------------------------------------------------------------------------ 2 FOMALHAUT STIS/CCD ACCUM WEDGEA1.8 MIRROR CR-SPLIT=NO, GAIN=4 4 .5 S see below (6 S) Comments: This is following the proposal ID 8788 pre-imaging of the same background star. ------------------------------------------------------------------------------------------------------------------------------------ 3 FOMALHAUT-B STIS/CCD ACCUM 52X2 G750L 7751 CR-SPLIT=NO 5 369 S ACKGROUND-S see below OURCE-OFF (1890 S) Comments: The spectrum of the background star will be compared with ID:13434 and ID:8788 datasets. ------------------------------------------------------------------------------------------------------------------------------------ 4 CCDFLAT STIS/CCD ACCUM 52X2 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 CCDFLAT STIS/CCD ACCUM 0.3X0.09 G750L 7751 2 DEF (0 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 | ------------------------------------------------------------------------------------------------------------------------------------ FOMALHAUT 1 STIS/CCD ACQ F25ND5 MIRROR none none none none 1 N/A FOMALHAUT 2 STIS/CCD ACCUM WEDGEA1. MIRROR none none 1 none 1 1.5 S 8 FOMALHAUT 2 STIS/CCD ACCUM WEDGEA1. MIRROR none none 2 none 1 1.5 S 8 FOMALHAUT 2 STIS/CCD ACCUM WEDGEA1. MIRROR none none 3 none 1 1.5 S 8 FOMALHAUT 2 STIS/CCD ACCUM WEDGEA1. MIRROR none none 4 none 1 1.5 S 8 FOMALHAUT-BACKGROUN 3 STIS/CCD ACCUM 52X2 G750L 7751 none none 1 none 1 378.0 S D-SOURCE-OFF FOMALHAUT-BACKGROUN 3 STIS/CCD ACCUM 52X2 G750L 7751 none none 2 none 1 378.0 S D-SOURCE-OFF FOMALHAUT-BACKGROUN 3 STIS/CCD ACCUM 52X2 G750L 7751 none none 3 none 1 378.0 S D-SOURCE-OFF 15297( 3) - 14-Jul-2017 17:44:22 - [ 4] 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 | ------------------------------------------------------------------------------------------------------------------------------------ FOMALHAUT-BACKGROUN 3 STIS/CCD ACCUM 52X2 G750L 7751 none none 4 none 1 378.0 S D-SOURCE-OFF FOMALHAUT-BACKGROUN 3 STIS/CCD ACCUM 52X2 G750L 7751 none none 5 none 1 378.0 S D-SOURCE-OFF CCDFLAT 4 STIS/CCD ACCUM 52X2 G750L 7751 none none 1 none 1 N/A CCDFLAT 4 STIS/CCD ACCUM 52X2 G750L 7751 none none 2 none 1 N/A CCDFLAT 5 STIS/CCD ACCUM 0.3X0.09 G750L 7751 none none 1 none 1 N/A CCDFLAT 5 STIS/CCD ACCUM 0.3X0.09 G750L 7751 none none 2 none 1 N/A 15297( 3) - 14-Jul-2017 17:44:22 - [ 5] Summary Form for Proposal 15297 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.3X0.09, 52X2, F25ND5, WEDGEA1.8 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO, GAIN=4 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 217D TO 281 D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G750L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names CCDFLAT, FOMALHAUT, FOMALHAUT-BACKGROUND-SOURCE-OFF ------------------------------------------------------------------------------------------------------------------------------------