12909( 13) - 13-Nov-2013 20:54:37 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12909 Version: 13 Check-in Time: 13-Nov-2013 20:54:37 STScI Edit Number: 4 Title WFC3 Micro-arcsecond astrometry of the possible SNIa progenitor BPM 71214 ------------------------------------------------------------------------------------ Type Cycle GO 20 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. John Henry Debes Space Telescope Science Institute Y CoI: Prof. Boris T. Gaensicke The University of Warwick Y CoI: Dr. Stefano Casertano Space Telescope Science Institute Y CoI: Dr. Adam Riess Space Telescope Science Institute Y CoI: Prof. Detlev G. Koester Universitat Kiel Y CoI: Dr. Elme Breedt The University of Warwick Y CoI: Dr. John W. MacKenty Space Telescope Science Institute Y ------------------------------------------------------------------------------------ Abstract We propose to use the newly commissioned scanning mode on WFC3 to obtain astrometric measurements of the ~0.008 AU WD/M dwarf binary BPM 71214. This system is a fascinating mystery for post-common envelope binary evolution and may be a SN1a progenitor. COS spectra of the WD in the system shows that it is rapidly rotating with a vsin i of 200 km/s, implying that it has already accreted significant mass from its companion, but mass transfer has since stopped. The COS spectra imply a near Chandrasekar mass for the WD, while optical spectroscopy suggests a mass of 0.8 M_Sun. We propose to take four orbits of WFC3 observations in scanning mode to obtain astrometric measurements of this system at a per-measurement precision of ~30~micro-arcseconds. Such measurements will definitively constrain the mass of the WD and fully solve for both masses in the binary. ------------------------------------------------------------------------------------ Observations Description ------------------------ We wish to obtain spatial scans along the xpos and ypos directions of BPM 71214 (LL Eri) in order to obtain high precision astrometric measurements relative to comparison stars in order to resolve its orbital motion between an M dwarf and WD. We attempt this using a combination of Red (F814W) and Blue (F390W) scans. The first two orbits we plan to take spatial scans only in the Red filters to accurately determine the orientation of the orbit on the sky. This will allow us to maximize our sensitivity by aligning our subsequent scan direction perpendicular to the maximum elongation direction of the binary orbit on the sky. We wish to have two consecutive HST orbits for both sets of observations, to ensure measurements that roughly overlap in orbital phase. We wish to make sure that our orbits begin at approximately orbital phase=0.25+/-0.05 or 0.75+/-0.050, whichever is more schedualable. The ephemeris currently has unacceptably large uncertainty, but we should have an updated ephemeris within a few weeks. Real Time Justification ----------------------- 12909( 13) - 13-Nov-2013 20:54:37 - [ 2] Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 12909( 13) - 13-Nov-2013 20:54:37 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V-LL-ERI STAR, DA RA=03H32M43.4518S +/- 0.5", J2000 V = 14.6 DEC=-08D55'39.32" +/- 0.5" Reference Frame: ICRS Comments: Target coordinates also confirmed with coordinates from GO 12474 This object was generated by the targetselector and retrieved from the SIMBAD database.This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1998.936 0.008023873847704333 -0.09440000000000001 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 12909( 13) - 13-Nov-2013 20:54:37 - [ 4] Visit: 01 Visit Requirements: SCHED 100%; ORIENT 309D TO 330 D; ORIENT 39D TO 60 D; ORIENT 129D TO 150 D; Period 0.201626 D AND ZERO-PHASE HJD2452318.102 On Hold Comments: Additional Comments: Take scans in Xpos and Ypos directions in F814W, starting from the UVIS1 point. Scans should be ~2000 (X), 1000 (Y) pixels in length almost aligned with Xpos and Ypos directions, but slightly off to allow pixel boundary crossings. Ideally we want to start the target and its reference, which is at a separation of ~16.3" and a PA of 324.8 degrees, in a region of the detector least affected by detector and geometric distortion effects. 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 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 496 S (496 POS TARG 10, null; S S) SPATIAL SCAN 0.15, 183.65 Degrees, Forward; PHASE 0.205 TO 0.230; GS ACQ SCENARIO BASE1B3; SEQ 1-4 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 495 S (495 POS TARG -15, null; S S) SPATIAL SCAN 0.07, 90.05 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 3 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 496 S (496 POS TARG 10, 0; SPATIAL S S) SCAN 0.15, 183.65 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 4 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 494 S (494 POS TARG -15, null; S S) SPATIAL SCAN 0.08, 90.05 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 5 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 532 S (532 POS TARG 15, null; S S) SPATIAL SCAN 0.15, 183.65 Degrees, Forward; SEQ 5-8 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 6 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 529 S (529 POS TARG -15, -10; S S) SPATIAL SCAN 0.08, 90.05 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 7 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 533 S (533 POS TARG 15, null; S S) SPATIAL SCAN 0.15, 183.65 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 8 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 529 S (529 POS TARG -15, -10; S S) SPATIAL SCAN 0.08, 90.05 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 12909( 13) - 13-Nov-2013 20:54:37 - [ 5] 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 | ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-LL-ERI 1 WFC3/UVI ACCUM UVIS1 F814W none none none none 1 N/A S V-LL-ERI 2 WFC3/UVI ACCUM UVIS1 F814W none none none none 1 N/A S V-LL-ERI 3 WFC3/UVI ACCUM UVIS1 F814W none none none none 1 N/A S V-LL-ERI 4 WFC3/UVI ACCUM UVIS1 F814W none none none none 1 N/A S V-LL-ERI 5 WFC3/UVI ACCUM UVIS1 F814W none none none none 2 N/A S V-LL-ERI 6 WFC3/UVI ACCUM UVIS1 F814W none none none none 2 N/A S V-LL-ERI 7 WFC3/UVI ACCUM UVIS1 F814W none none none none 2 N/A S V-LL-ERI 8 WFC3/UVI ACCUM UVIS1 F814W none none none none 2 N/A S 12909( 13) - 13-Nov-2013 20:54:37 - [ 6] Visit: 02 Visit Requirements: SCHED 100%; ORIENT 309D TO 330 D; ORIENT 39D TO 60 D; ORIENT 129D TO 150 D; Period 0.201626 D AND ZERO-PHASE HJD2452318.102 On Hold Comments: Additional Comments: Same as Visit 1 but with F814W and F390W 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 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 492 S (492 POS TARG 10, null; S S) SPATIAL SCAN 0.15, 183.65 Degrees, Forward; PHASE 0.205 TO 0.230; GS ACQ SCENARIO BASE1B3; SEQ 1-4 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 487 S (487 POS TARG -15, null; S S) SPATIAL SCAN 0.07, 90.05 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 3 V-LL-ERI WFC3/UVI ACCUM UVIS1 F390W 1 492 S (492 POS TARG 10, 0; SPATIAL S S) SCAN 0.15, 183.65 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 4 V-LL-ERI WFC3/UVI ACCUM UVIS1 F390W 1 486 S (486 POS TARG -15, null; S S) SPATIAL SCAN 0.07, 90.05 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 5 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 522 S (522 POS TARG 15, null; S S) SPATIAL SCAN 0.15, 183.65 Degrees, Forward; SEQ 5-8 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 6 V-LL-ERI WFC3/UVI ACCUM UVIS1 F814W 1 517 S (517 POS TARG -15, null; S S) SPATIAL SCAN 0.07, 90.05 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 7 V-LL-ERI WFC3/UVI ACCUM UVIS1 F390W 1 522 S (522 POS TARG 15, null; S S) SPATIAL SCAN 0.15, 183.65 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 8 V-LL-ERI WFC3/UVI ACCUM UVIS1 F390W 1 517 S (517 POS TARG -15, null; S S) SPATIAL SCAN 0.07, 90.05 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ 12909( 13) - 13-Nov-2013 20:54:37 - [ 7] 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 | ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-LL-ERI 1 WFC3/UVI ACCUM UVIS1 F814W none none none none 1 N/A S V-LL-ERI 2 WFC3/UVI ACCUM UVIS1 F814W none none none none 1 N/A S V-LL-ERI 3 WFC3/UVI ACCUM UVIS1 F390W none none none none 1 N/A S V-LL-ERI 4 WFC3/UVI ACCUM UVIS1 F390W none none none none 1 N/A S V-LL-ERI 5 WFC3/UVI ACCUM UVIS1 F814W none none none none 2 N/A S V-LL-ERI 6 WFC3/UVI ACCUM UVIS1 F814W none none none none 2 N/A S V-LL-ERI 7 WFC3/UVI ACCUM UVIS1 F390W none none none none 2 N/A S V-LL-ERI 8 WFC3/UVI ACCUM UVIS1 F390W none none none none 2 N/A S 12909( 13) - 13-Nov-2013 20:54:37 - [ 8] Summary Form for Proposal 12909 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO BASE1B3, ORIENT 129D TO 150 D, ORIENT 309D TO 330 D, ORIENT 39D TO 60 D, PHASE 0.205 TO 0.230, POS TARG -15, -10, POS TARG -15, null, POS TARG 10, 0, POS TARG 10, null, POS TARG 15, null, Period 0.201626 D AND ZERO-PHASE HJD2452318.102 , SCHED 100%, SEQ 1-4 NON-INT, SEQ 5-8 NON-INT, SPATIAL SCAN 0.07, 90.05 Degrees, Forward, SPATIAL SCAN 0.08, 90.05 Degrees, Forward, SPATIAL SCAN 0.15, 183.65 Degrees, Forward ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F390W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names V-LL-ERI ------------------------------------------------------------------------------------------------------------------------------------