15511( 6) - 14-Dec-2018 18:54:54 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15511 Version: 6 Check-in Time: 14-Dec-2018 18:54:54 STScI Edit Number: 1 Title Measurement of the Expansion Proper Motions of the Ou4 Giant Bipolar Outflow to Determine its Distance and its True Nature ------------------------------------------------------------------------------------ Type Cycle GO 26 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Nicolas Grosso Laboratoire d'Astrophysique de Marseille Y CoI: Dr. Romano Luigi Maria Corradi Instituto de Astrofisica de Canarias N CoI: Prof. Agnes Acker Universite de Strasbourg I N ------------------------------------------------------------------------------------ Abstract Ou4 is a giant bipolar outflow with a total length of 1.2 degrees on the sky that was discovered in the optical in the direction of the blister HII region Sh2-129. The distance, the nature, and the driving source of Ou4 are, however, not known. Ou4 is relevant for the study of the eruptive phenomena producing collimated outflows from evolved low-mass binary stars and young, massive stellar systems. Our morpho-kinematics study of the Ou4 south bow-shock has allowed us to predict its expansion proper motion that is directly related to its distance. We propose to image the brightest [O III] emission of this bow-shock with the UVIS channel of the WFC3 in Cycle 24 and 26 in order to determine the distance of this largest known stellar bipolar outflow from its expansion proper motions. This measurement is crucial to determine the true nature of Ou4: either a foreground planetary nebula or a giant bipolar outflow launched ~90, 000 years ago by HR 8119, the young massive triple system ionising Sh2-129. ------------------------------------------------------------------------------------ Observations Description ------------------------ The first epoch observation was obtained on 2016-10-23 with ORIENT=78.8 degrees. To increase the time separation between the first and this second observation, we increase ORIENT of about 180 degrees to allow scheduling in May 2019 and consequently change the pointing to survey the same area of the bow shock. We use the observing strategy of the first epoch observation. We use the WFC3/UVIS channel with the F502N narrow filter to survey the brightest emission of the 5007 A line of the [O III] doublet in the Ou4 giant bipolar outflow. We execute dithered exposures using the B6 pattern (pre-defined WFC3-UVIS-MOS-DITH-LINE pattern has been modified), which combines two step over the chip gap to maximize the surveyed area and sub-pixel steps to improve the PSF sampling (WFC3 ISR 2010-09). The six frames are executed inside the same orbit for the best dither pointing accuracy. We use parallel buffer dumps. We add a flash at the end of each exposure (12 electrons) to reduce the charge losses during the detector readouts. 15511( 6) - 14-Dec-2018 18:54:54 - [ 2] ------------------------------------------------------------------------------------ 15511( 6) - 14-Dec-2018 18:54:54 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 OU4-SOUTH-LO ISM, BIPOLAR OUTFLOW, RA=21H13M23.4580S, J2000 2.25E-16 BE EMISSION LINE NEBULA, DEC=+59D24'26.96" HII REGION, SHOCK FRONT, WIND Reference Frame: ICRS Extended: YES Comments: The target is extended and has a very small expansion proper motion. The pointing coordinates are optimized to maximize the emission survey. The flux is our surface brightness threshold in erg/s/cm2/arcsec2. ------------------------------------------------------------------------------------------------------------------------------------ 15511( 6) - 14-Dec-2018 18:54:54 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-MOS-DITH-LINE WFC3-UVIS-MOS-DITH-LINE Pattern_Purpose DITHER DITHER Number_Of_Points 3 2 Point_Spacing 2.632 0.119 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 47.134 33.715 Angle_Between_Sides Center_Pattern YES NO Pattern_Comments: Pre-defined WFC3-UVIS-MOS-DITH-LINE pattern has been modified to obtain B6 pattern (WFC3 ISR 2010-09). ------------------------------------------------------------------------------------------------------------------------------------ 15511( 6) - 14-Dec-2018 18:54:54 - [ 5] Visit: 01 (second epoch imaging) Visit Requirements: ORIENT 252D TO 256 D On Hold Comments: Additional Comments: Two consecutive orbits. We require a specific orientation to maximize the time baseline, to survey the same area of the bow shock that was observed in 2016, and to put a V=10.7-mag star in quadrant C to prevent any filter and window ghost artifacts (the latter being produced in a such narrow filter image by star with V<12 mag in quadrant D; WFC3 ISR 2011-16) that would disturb our proper motion measurement. We use an angle tolerance to increase the schedulability (16-26 May 2019). 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 OU4-SOUTH-L WFC3/UVI ACCUM UVIS F502N FLASH=12 1 1000 S PATTERN 1 1 OBE S see below (2373 S) Comments: We add a flash at the end of each exposure (12 electrons) to reduce the charge losses during the detector readouts. ------------------------------------------------------------------------------------------------------------------------------------ 2 OU4-SOUTH-L WFC3/UVI ACCUM UVIS F502N FLASH=12 1 1000 S PATTERN 1 2 OBE S see below (2404 S) Comments: We add a flash at the end of each exposure (12 electrons) to reduce the charge losses during the detector readouts. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ OU4-SOUTH-LOBE 1 WFC3/UVI ACCUM UVIS F502N 1 1 none none 1 396.0 S S OU4-SOUTH-LOBE 1 WFC3/UVI ACCUM UVIS F502N 1 2 none none 1 395.0 S S OU4-SOUTH-LOBE 1 WFC3/UVI ACCUM UVIS F502N 2 1 none none 1 396.0 S S OU4-SOUTH-LOBE 1 WFC3/UVI ACCUM UVIS F502N 2 2 none none 1 395.0 S S OU4-SOUTH-LOBE 1 WFC3/UVI ACCUM UVIS F502N 3 1 none none 1 396.0 S S OU4-SOUTH-LOBE 1 WFC3/UVI ACCUM UVIS F502N 3 2 none none 1 395.0 S S OU4-SOUTH-LOBE 2 WFC3/UVI ACCUM UVIS F502N 1 1 none none 2 401.0 S S OU4-SOUTH-LOBE 2 WFC3/UVI ACCUM UVIS F502N 1 2 none none 2 400.0 S S 15511( 6) - 14-Dec-2018 18:54:54 - [ 6] 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 | ------------------------------------------------------------------------------------------------------------------------------------ OU4-SOUTH-LOBE 2 WFC3/UVI ACCUM UVIS F502N 2 1 none none 2 401.0 S S OU4-SOUTH-LOBE 2 WFC3/UVI ACCUM UVIS F502N 2 2 none none 2 400.0 S S OU4-SOUTH-LOBE 2 WFC3/UVI ACCUM UVIS F502N 3 1 none none 2 401.0 S S OU4-SOUTH-LOBE 2 WFC3/UVI ACCUM UVIS F502N 3 2 none none 2 401.0 S S 15511( 6) - 14-Dec-2018 18:54:54 - [ 7] Summary Form for Proposal 15511 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=12 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 252D TO 256 D, PATTERN 1 1, PATTERN 1 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F502N ------------------------------------------------------------------------------------------------------------------------------------ Target Names OU4-SOUTH-LOBE ------------------------------------------------------------------------------------------------------------------------------------