0 Assigned ID: 73 ----- Attempting Submission 1 (Tue Apr 07 06:35:18 GMT 2015) ----- If the target coordinates are not known to 0.4" (or better), an ACQ/SEARCH should precede the ACQ/IMAGE. If the target coordinates are not known to 0.4" (or better), an ACQ/SEARCH should precede the ACQ/IMAGE. If the target coordinates are not known to 0.4" (or better), an ACQ/SEARCH should precede the ACQ/IMAGE. If the target coordinates are not known to 0.4" (or better), an ACQ/SEARCH should precede the ACQ/IMAGE. If the target coordinates are not known to 0.4" (or better), an ACQ/SEARCH should precede the ACQ/IMAGE. If the target coordinates are not known to 0.4" (or better), an ACQ/SEARCH should precede the ACQ/IMAGE. If the target coordinates are not known to 0.4" (or better), an ACQ/SEARCH should precede the ACQ/IMAGE. Two targets were removed as they were already observed or scheduled for observation by COS. The extra orbits are used to increase the S/N of the fainter targets. 1447902497 ----- Attempting Submission 1 (Wed Jul 22 18:59:12 GMT 2015) ----- ----- Attempting Submission 2 (Wed Jan 13 16:32:54 GMT 2016) ----- ----- Attempting Submission 3 (Tue Apr 05 14:19:49 GMT 2016) ----- The target coordinates are known to 0.4". Connecting white dwarf rotation and debris accretion Recent Kepler photometry has revealed that half of white dwarfs have periodic, low-level (~10^-3-10^-4), optical variations. HST UV spectroscopy has shown that half of white dwarfs are actively accreting rocky planetary debris. By obtaining UV spectra of 9 WDs monitored with Kepler, we will test the hypothesis that these two phenomena are causally connected, i.e. that the optical periodic modulation is caused by WD rotation coupled with an inhomogeneous surface distribution of accreted metals. If there is a match between the periodically variable WDs and the WDs with UV line opacity, this will confirm the hypothesis. The Kepler photometric modulation will then be established as the first method that can provide reliable rotation periods for hundreds of normal WDs. WD rotation is a critical observable for understanding stellar evolution, stellar mass loss, Type-Ia supernova progenitors and more, but rotation periods have been measured for only tens of WDs, mainly rare magnetic ones. Furthermore, confirmation of the connection between UV line opacity and optical modulation will provide an inexpensive photometric probe for identifying accretion of rocky debris in large samples of WDs, and mapping its dependence on WD (and progenitor system) properties. If the hypothesis is rejected (there is no match between UV line opacity and optical modulation), this will point to alternative and no-less-interesting explanations for the optical variability, e.g. the abundant presence of close-in companions to WDs, such as giant planets or secondary cool WDs. Sample Selection: To test the correspondence between the existence of periodic optical variability and the presence of UV metal absorption lines in WDs, we will observe 9 WDs that have been monitored for low-level variability with good S/N: four WDs that have clear periodic modulation, and five that do not, with upper limits on any periodic variability at amplitude levels below 100 ppm (i.e. 10^-4 ). Additional selection criteria for all 9 WDs are: visual magnitude < 18 mag, to ensure sufficient S/N; effective temperatures T eff < 32000K, to avoid WDs in which radiative levitation plays a role in the presence of atmospheric metals; surface gravity 7.5 < log g < 8.5, to include only bona-fide normal WDs of the kind whose UV metal pollution has been studied. The choice of 9 WDs will permit, in principle, to significantly reject the null hypothesis that optical modulations and UV metal pollution are unrelated. Assuming that in two of the nine WDs there could be a mismatch between the presence of optical modulation and UV metal lines, due to a different cause for the modulation (e.g. rotation plus magnetic dichroism, or beaming due to a close companion), this would still leave seven WDs with a match between the two effects. Since the probability of any WD to display each effect alone is ~50% (Koester et al., 2014; Maoz et al., 2015), the chance probability for seven matches would be 2^-7 < 1%, and thus seven or more matches will firmly reject the null hypothesis. Observations: Each WD will be observed for one orbit with COS/FUV, except for the three faint WDs with no FUV magnitude measurements, which will be observed for two orbits, in order to achieve higher S/N, as two WDs of our sample were already observed/scheduled for observation by COS. For acquisition we will generally use the COS/NUV ACQ/IMAGE mode with MirrorB. For two of the targets, which are too bright to be acquired with ACQ/IMAGE, we will use instead COS/FUV with ACQ/PEAKXD and ACQ/PEAKD modes. Science exposures will be taken using the TIME-TAG mode by the G130M grating of COS/FUV with a central wavelength of 1291A, which will cover the wavelength range 1130-1435A. We will dither the exposures over the four FP-POS settings in order to remove fixed pattern noise. We will fill each orbit with a net exposure time of ~35 min, to get a S/N ~ 10 per resolution element, more than adequate for detecting and measuring the UV metal lines. HOT STARS 12 false true false false false false SUPPORTED STAR DA NO A<50 ppm, T=16kK, DA E(B-V)=0.111 J2000 J2000 STAR DA NO A<70 ppm, T=14kK, DA E(B-V)=0.058 J2000 J2000 GALEX FUV=16.5AB STAR DB NO P=0.6 d, A=500 ppm, T~34kK, DB E(B-V)=0.112 Temperature according to SED J2000 J2000 GALEX FUV=16.7AB, GALEX NUV=16.8AB STAR DA NO P=0.37d,A=800 ppm,T=30.5kK DA E(B-V)=0.081 J2000 J2000 GALEX FUV=16.2AB STAR DA NO P=0.09 d, A=300 ppm,T=23kK, DA E(B-V)=0.043 J2000 J2000 GALEX FUV=15.2AB STAR DA NO A<50 ppm. T=19kK, DA E(B-V)=0.1118 J2000 J2000 STAR DA NO A<80 ppm, T=24kK, DA+DA E(B-V) = 0.1513 J2000 J2000 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 The scheduling data was generated by CASM 24.0. CASM was run in Phase II mode. /home/naama/Dropbox/University/PhD/Research/WD/HST/OP-cache/PhaseII_revision2-v01.xml (Tic-Visit :proposal-id 14082 :visit-id "01" :proposal-version -1 :trans-version "20160129" :date "05-Apr-2016 17:09:00.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 156736 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14082 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14082 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3018 :al-overhead-at-end 0 :internal-dur-at-end 67 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3352 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14082 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3130 :al-overhead-at-end 0 :internal-dur-at-end 360 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3352 :pcs-gap 0 ) true 2 0 Exposure time (seconds) = 5,437.0000 at wavelength 1310.00A gives: SNR = 10.7515 (per resolution element) The scheduling data was generated by CASM 24.0. CASM was run in Phase II mode. /home/naama/Dropbox/University/PhD/Research/WD/HST/OP-cache/PhaseII_revision2-v02.xml (Tic-Visit :proposal-id 14082 :visit-id "02" :proposal-version -1 :trans-version "20160129" :date "05-Apr-2016 17:09:01.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 87168 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14082 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14082 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3019 :al-overhead-at-end 0 :internal-dur-at-end 341 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3352 :pcs-gap 0 ) true 1 0 Exposure time (seconds) = 2,275.0000 at wavelength 1310.00A gives: SNR = 10.4222 (per resolution element) The scheduling data was generated by CASM 24.0. CASM was run in Phase II mode. /home/naama/Dropbox/University/PhD/Research/WD/HST/OP-cache/PhaseII_revision2-v03.xml (Tic-Visit :proposal-id 14082 :visit-id "03" :proposal-version -1 :trans-version "20160129" :date "05-Apr-2016 17:09:02.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 121920 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14082 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14082 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2974 :al-overhead-at-end 0 :internal-dur-at-end 350 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3307 :pcs-gap 0 ) true 1 0 Exposure time (seconds) = 2,227.0000 at wavelength 1310.00A gives: SNR = 12.6901 (per resolution element) The scheduling data was generated by CASM 24.0. CASM was run in Phase II mode. /home/naama/Dropbox/University/PhD/Research/WD/HST/OP-cache/PhaseII_revision2-v04.xml (Tic-Visit :proposal-id 14082 :visit-id "04" :proposal-version -1 :trans-version "20160129" :date "05-Apr-2016 17:09:03.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 87168 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14082 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14082 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2974 :al-overhead-at-end 0 :internal-dur-at-end 341 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3307 :pcs-gap 0 ) true 1 0 Exposure time (seconds) = 2,218.0000 at wavelength 1310.00A gives: SNR = 15.9079 (per resolution element) The scheduling data was generated by CASM 24.0. CASM was run in Phase II mode. /home/naama/Dropbox/University/PhD/Research/WD/HST/OP-cache/PhaseII_revision2-v05.xml (Tic-Visit :proposal-id 14082 :visit-id "05" :proposal-version -1 :trans-version "20160129" :date "05-Apr-2016 17:09:04.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 156736 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14082 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14082 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3019 :al-overhead-at-end 0 :internal-dur-at-end 360 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3352 :pcs-gap 0 ) true 1 0 Exposure time (seconds) = 2,284.0000 at wavelength 1310.00A gives: SNR = 24.2557 (per resolution element) The scheduling data was generated by CASM 24.0. CASM was run in Phase II mode. /home/naama/Dropbox/University/PhD/Research/WD/HST/OP-cache/PhaseII_revision2-v06.xml (Tic-Visit :proposal-id 14082 :visit-id "06" :proposal-version -1 :trans-version "20160129" :date "05-Apr-2016 17:09:05.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 208864 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14082 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14082 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2933 :al-overhead-at-end 0 :internal-dur-at-end 76 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3267 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14082 :visit-id "06" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3045 :al-overhead-at-end 0 :internal-dur-at-end 379 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3267 :pcs-gap 0 ) true 2 0 Exposure time (seconds) = 5,275.0000 at wavelength 1310.00A gives: SNR = 18.7255 (per resolution element) The scheduling data was generated by CASM 24.0. CASM was run in Phase II mode. /home/naama/Dropbox/University/PhD/Research/WD/HST/OP-cache/PhaseII_revision2-v07.xml (Tic-Visit :proposal-id 14082 :visit-id "07" :proposal-version -1 :trans-version "20160129" :date "05-Apr-2016 17:09:06.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 208864 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14082 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14082 :visit-id "07" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2974 :al-overhead-at-end 0 :internal-dur-at-end 76 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3307 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14082 :visit-id "07" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3085 :al-overhead-at-end 0 :internal-dur-at-end 379 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3307 :pcs-gap 0 ) true 2 0 Exposure time (seconds) = 5,332.0000 at wavelength 1310.00A gives: SNR = 17.2929 (per resolution element)