Updated scan rates for Visit 2 so the target does not run off the chip. Everything else is the same. 492850999 ----- Attempting Submission 6 (Fri Mar 29 11:36:44 GMT 2013) ----- ----- Attempting Submission 7 (Tue Apr 02 15:51:36 GMT 2013) ----- ----- Attempting Submission 8 (Wed Nov 13 20:45:59 GMT 2013) ----- 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. 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. HOT STARS 12 false false 0.0 0.0 false false false SUPPORTED STAR DA 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. J2000 J2000 WFC3/UVIS Imaging No No F390W WFC3/UVIS Imaging No No F814W Phase windows are not calculated when the gap between schedulable intervals is less than 1 days, assuming no scheduling restrictions for constraint Phase 0.205/0.230. The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. /private/var/folders/9d/jk8g77fd2jx3sxdb33rhwx48000300/T/OPVisit3873058824799135466.xml 1384375494986 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. 1384147643000 330.0 (Tic-Visit :proposal-id 12909 :visit-id "01" :proposal-version -1 :trans-version "20130502" :date "13-Nov-2013 15:44:54.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2310000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12909 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12909 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2682 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3015 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12909 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2793 :al-overhead-at-end 0 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3015 :pcs-gap 0 ) true 2 0 Phase windows are not calculated when the gap between schedulable intervals is less than 1 days, assuming no scheduling restrictions for constraint Phase 0.205/0.230. The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. /private/var/folders/9d/jk8g77fd2jx3sxdb33rhwx48000300/T/OPVisit2422702474184509109.xml 1384375529107 Same as Visit 1 but with F814W and F390W (Tic-Visit :proposal-id 12909 :visit-id "02" :proposal-version -1 :trans-version "20130502" :date "13-Nov-2013 15:45:28.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2310000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12909 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12909 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2682 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3015 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12909 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2793 :al-overhead-at-end 0 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3015 :pcs-gap 0 ) true 2 0