0 Assigned ID: 1310 ----- Attempting Submission 1 (Thu Feb 28 23:08:49 GMT 2013) ----- HST Phase I Proposal 1310 (stein1.apt) successfully submitted. ----- Attempting Submission 2 (Thu Feb 28 23:48:33 GMT 2013) ----- HST Phase I Proposal 1310 (stein1.apt) successfully submitted. ----- Attempting Submission 3 (Sat Mar 02 00:31:36 GMT 2013) ----- HST Phase I Proposal 1310 (stein1.apt) successfully submitted. ----- Attempting Submission 4 (Sun Mar 03 15:30:47 GMT 2013) ----- Visit 6 is now ready to execute. Thanks! -380850664 ----- Attempting Submission 1 (Tue Jul 02 19:46:40 GMT 2013) ----- HST Phase II Proposal 13457 (13457.apt) successfully submitted. ----- Attempting Submission 2 (Tue Jul 02 20:02:52 GMT 2013) ----- ----- Attempting Submission 3 (Fri Sep 06 23:27:21 GMT 2013) ----- HST Phase II Proposal 13457 (13457.apt) successfully submitted. ----- Attempting Submission 4 (Thu Sep 12 15:06:24 GMT 2013) ----- HST Phase II Proposal 13457 (13457.apt) successfully submitted. ----- Attempting Submission 5 (Thu Sep 12 15:06:36 GMT 2013) ----- ----- Attempting Submission 6 (Fri Dec 20 23:38:36 GMT 2013) ----- ----- Attempting Submission 7 (Mon Jan 27 23:48:59 GMT 2014) ----- HST Phase II Proposal 13457 (13457_vis3.apt) successfully submitted. ----- Attempting Submission 8 (Tue Jan 28 18:24:40 GMT 2014) ----- HST Phase II Proposal 13457 (13457_v.apt) successfully submitted. ----- Attempting Submission 9 (Wed Jan 29 17:45:31 GMT 2014) ----- HST Phase II Proposal 13457 (13457_v.apt) successfully submitted. ----- Attempting Submission 10 (Wed Jan 29 17:49:48 GMT 2014) ----- ----- Attempting Submission 11 (Thu Jan 30 04:29:29 GMT 2014) ----- ----- Attempting Submission 12 (Wed Mar 05 15:08:03 GMT 2014) ----- ----- Attempting Submission 13 (Mon Apr 21 18:02:18 GMT 2014) ----- Visits6 ready. Accurate Mass Determination of the Nearby Old White Dwarf Stein 2051B through Astrometric Microlensing The very nearby and well-known cool white dwarf (WD) Stein 2051B will pass very close to a 19.5-mag background star in March 2014, with an impact parameter of <0.2 arcsec. This affords a unique opportunity for a direct determination of its mass, through measurement of the gravitational deflection of the background star's image. As it passes in front, Stein 2051B will cause a deflection of the background star's image by ~3 milliarcsec, an amount detectable at the ~10-sigma level with HST/WFC3. The gravitational deflection angle depends only on the distances and relative positions of the stars, and on the mass of the WD. Since the distances and positions can be determined precisely before the event, the astrometric measurement offers a unique and direct method to measure the mass of the WD to high accuracy (<5%). One key astrophysical prediction for WDs is the existence of a mass-radius relation, which depends primarily on the core composition of the WD. Since the radius of Stein 2051B is known (from its distance, luminosity, and effective temperature), our mass measurement will provide an important addition to the very small number of WDs with well-determined radii and masses. The mass of Stein 2051B is of special interest because it is an old and relatively massive WD. We need to know accurate locations and proper motions for Stein 2051B and the source star, in order to predict the precise circumstances of the event, including the date and impact parameter. The existing ground-based measurements do not have the 1 mas accuracy needed for these purposes, especially given the 6.5 mas/day proper motion of Stein 2051B. Therefore, we will use direct imaging with WFC3 to determine the astrometric parameters of Stein 2051B, the source star, and the surrounding reference field. These determinations need to be done well in advance of the closest encounter in March 2014, beginning in Cycle 21. The maximum deflection of the source position that is actually observable occurs just before the images of the two stars become blended (at HST resolution), which happens about 30 days before closest approach (and 30 days after closest approach). So, we need to know the time of closest approach as accurately as possible in order to schedule these two critical observations. Additional observations should be scheduled before and after those critical times, when the deflection is changing most rapidly with time. COOL STARS 12 false false 0.0 0.0 false false false AVAILABLE STAR DA This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 STAR DA This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 STAR DA This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 STAR DA This target will put LHS26 at the same location of STEIN 2051B in the target STEIN-2051B-SOURCE. J2000 J2000 WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F475W The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. ORIENT constraints are used to avoid diffraction spikes and bleed columns from Stein 2051A and B falling near the faint source star 1380585748000 228.10000000000002 (Tic-Visit :proposal-id 13457 :visit-id "01" :proposal-version -1 :trans-version "20130722" :date "12-Sep-2013 11:03:10.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 633488 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13457 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13457 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2811 :al-overhead-at-end 170 :internal-dur-at-end 652 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3491 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1388982673000 122.0 (Tic-Visit :proposal-id 13457 :visit-id "02" :proposal-version -1 :trans-version "20130722" :date "20-Dec-2013 18:30:59.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 633488 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13457 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13457 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2911 :al-overhead-at-end 170 :internal-dur-at-end 498 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3491 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 62 1392044971000 115.0 (Tic-Visit :proposal-id 13457 :visit-id "03" :proposal-version -1 :trans-version "20131031" :date "29-Jan-2014 22:41:15.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 348400 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13457 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13457 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3380 :al-overhead-at-end 174 :internal-dur-at-end 417 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3720.0 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 22.0. CASM was run in Phase II mode. 54 1395887303000 70.0 (Tic-Visit :proposal-id 13457 :visit-id "04" :proposal-version -1 :trans-version "20131031" :date "02-Mar-2014 20:10:16.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 385008 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13457 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13457 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2877 :al-overhead-at-end 174 :internal-dur-at-end 457 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3240.0 :pcs-gap 0 ) true 1 0 We need to analyze the previous visit HST data before this can be finalyzed. The scheduling data was generated by CASM 22.0. CASM was run in Phase II mode. 54 1396619356000 65.0 (Tic-Visit :proposal-id 13457 :visit-id "05" :proposal-version -1 :trans-version "20131031" :date "02-Mar-2014 20:12:42.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 385008 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13457 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13457 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2877 :al-overhead-at-end 174 :internal-dur-at-end 457 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3240.0 :pcs-gap 0 ) true 1 0 We need to analyze the previous visit HST data before this can be finalyzed. The scheduling data was generated by CASM 22.0. CASM was run in Phase II mode. 54.5 /private/var/folders/sq/f89n76pn0v36vqjlw3x3d0f40000gn/T/OPVisit4551695260320492698.xml (Tic-Visit :proposal-id 13457 :visit-id "06" :proposal-version -1 :trans-version "20131031" :date "21-Apr-2014 19:28:38.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 427792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13457 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13457 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2909 :al-overhead-at-end 83 :internal-dur-at-end 504 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3270.0 :pcs-gap 0 ) true 1 0 We need to analyze the previous visit HST data before this can be finalyzed.