HST Observations of Astrophysically Important Visual Binaries

SHORT FGS SCAN LENGTH MAY SIGNAL PROBLEMS 0 ----- Attempting Submission 1 (Tue Jul 15 00:05:38 GMT 2014) ----- warning of short scans is to be ignored. HST Observations of Astrophysically Important Visual Binaries We propose to continue our long-term program of astrometry of close visual binaries, with the primary goal of determining purely dynamical masses for 3 important main-sequence stars and 9 white dwarfs (WDs). A secondary aim is to set limits on third bodies in the systems down to planetary mass. Three of our targets are naked-eye stars with much fainter companions that are extremely difficult to image from the ground. Our other 2 targets are double WDs, whose small separations and faintness likewise make them difficult to measure using ground-based techniques. Observations have been completed for a 3rd double WD. The bright stars, to be imaged with WFC3, are: (1) Procyon (P = 40.83 yr), containing a bright F star and a much fainter WD companion. With the continued monitoring proposed here, we will obtain masses to an accuracy of better than 1%, providing a testbed for theories of both Sun-like stars and WDs. (2) Sirius (P = 50.14 yr), an A-type star also having a faint WD companion, Sirius B, the nearest and brightest of all WDs. (3) Mu Cas (P = 21.08 yr), a nearby metal-deficient G dwarf for which accurate masses will lead to the stars' helium contents, with cosmological implications. The faint double WDs, to be observed with FGS, are: (1) G 107-70 (P = 18.84 yr), and (2) WD 1818+126 (P = 12.19 yr). Our astrometry of these systems will add 4 accurate masses to the handful of WD masses that are directly known from dynamical measurements. The FGS measurements will also provide precise parallaxes for the systems, a necessary ingredient in the mass determinations. This is the Cycle 22 continuation of a program in which we are determining the orbits of visual binaries. The targets for Cycle 22 are mu Cas, WD 1818+126, and G 107-70 We have been observing WD 1818+126 and G 107-70 with FGS, and this part of the program will continue as before, with 1 orbit of POS mode observations of the target and reference stars made for both of these target fields. Mu Cas will be observed with WFC3/UVIS. We will use 1.5-sec exposures in F225W, which will not be saturated. These will be followed at each dither position with a 265-sec exposure, which will be well exposed for the cool dM companion. COOL STARS 12 false true 0.0 0.0 false false false AVAILABLE STAR G V-IV Coordinate accuracy confirmed by 2000-01 WFPC2 observations. 6/14/06: updated to ICRS system using galex website. HR321 HD6582 J2000 J2000 B-V = 0.70 EXT-STAR DC maximum parallax factor occurs Sep 29 and March 29 J2000 J2000 CALIBRATION ASTROMETRIC GSC1018.02189 J2000 J2000 CALIBRATION ASTROMETRIC GSC1018.02278 J2000 J2000 CALIBRATION ASTROMETRIC GSC1018.01251 J2000 J2000 CALIBRATION ASTROMETRIC position and magnitude from GSC2, using Kriss & Stys color transformations. N020230030828 J2000 J2000 CALIBRATION ASTROMETRIC position and magnitude from GSC2, using Kriss & Stys color transformations N020230030566 J2000 J2000 CALIBRATION ASTROMETRIC position and magnitude from GSC2, using Kriss & Stys color transformation N020230031910 J2000 J2000 CALIBRATION ASTROMETRIC position and magnitude from GSC2, color transformation using Kriss & Stys N020230031978 J2000 J2000 STAR DC double degenerate binary system, separation ~0.6" J2000 J2000 STAR M V-IV CPM companion to G107-70, ~1 arcmin distant J2000 J2000 CALIBRATION ASTROMETRIC J2000 J2000 CALIBRATION ASTROMETRIC J2000 J2000 CALIBRATION ASTROMETRIC J2000 J2000 CALIBRATION ASTROMETRIC J2000 J2000 CALIBRATION ASTROMETRIC J2000 J2000 CALIBRATION ASTROMETRIC J2000 J2000 WFC3/UVIS Imaging No No F953N WFC3/UVIS Imaging No No F953N WFC3/UVIS Imaging No No F225W FGS POS No F583W FGS POS No F583W POS-TARG DITHER 0.173 LINE 0.112 false true 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 1

false

The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. 1405378967804 /Users/nelan/Desktop/OP-cache/13876-v02.xml ORIENT requirement is done so that companion star will not lie near diffraction spikes or charge bleeding of primary star. (Tic-Visit :proposal-id 13876 :visit-id "02" :proposal-version -1 :trans-version "20140605" :date "14-Jul-2014 19:02:47.0" :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 73232 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13876 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13876 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2963 :al-overhead-at-end 45 :internal-dur-at-end 117 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3319 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. 1405382594066 /private/var/folders/5n/j2_7w4n94ds83tmth7hz6_zm0005_1/T/OPVisit1593140947058982730.xml (Tic-Visit :proposal-id 13876 :visit-id "04" :proposal-version -1 :trans-version "20140605" :date "14-Jul-2014 20:03:13.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "05" :si-bright-earth-limb-angle 15.5 :data-volume 0 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13876 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13876 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2761 :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 3117 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. 1405380857022 /private/var/folders/5n/j2_7w4n94ds83tmth7hz6_zm0005_1/T/OPVisit519203571797977924.xml Maximum parallax factors April 10, October 11. This ORIENT can schedule up to April 6, and results in a favorable projection of the G107-70 components (PA ~ 272 degrees) in the FGS frame. (Tic-Visit :proposal-id 13876 :visit-id "05" :proposal-version -1 :trans-version "20140605" :date "14-Jul-2014 19:34:16.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "05" :si-bright-earth-limb-angle 15.5 :data-volume 0 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13876 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13876 :visit-id "05" :orbit-number 1 :pcs-time 241 :si-vis-utilization 3025 :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 3358 :pcs-gap 0 ) true 1 0