Accreting Pulsating White Dwarfs in Cataclysmic Variables

Accreting Pulsating White Dwarfs in Cataclysmic Variables Recent ground-based observations have increased the number of known pulsating white dwarfs in close binaries with active mass transfer (cataclysmic variables) from 5 to 11 systems. Our past Cycles 8 and 11 STIS observations of the first 2 known, followed by our Cycle 13 SBC observations of the next 3 discovered, revealed the clear presence of the white dwarf and increased amplitude of the pulsations in the UV compared to the optical. The temperatures derived from the UV spectra show 4 systems are much hotter than non-interacting pulsating white dwarfs. A larger sample is needed to sort out the nature of the instability strip in accreting pulsators i.e. whether effects of composition and rotation due to accretion result in a well-defined instability strip as a function of Teff.

Our proposed observations are identical to those proposed for Cycle 13 and successfully carried out in May-July of 2005. We will use the ACS with the SBC and prism PR110L in order to obtain UV coverage from about 1170-1800A. Our goals are to obtain both time-resolved coverage in order to construct UV light curves, as well as obtain a summed spectrum with sufficient S/N to allow a temperature fit with models. Thus, the number of orbits is driven by the need to have a sufficiently long baseline to identify the pulsation frequencies, and (almost) independent of the brightness of the target. Since the number of contiguous HST orbits is limited to 5, we therefore request 30 orbits (5 for each target). To accomplish both goals, we have devised the method of continual 60-61s integrations throughout each orbit. With a zero order exposure and setup in the first orbit, we are able to obtain 26-27 exposures in the first orbit and 27-28 in each of the 4 succeeding orbits for a total of 136-138 min of exposure on each of our 6 targets. This exposure time is sufficient to provide a summed spectrum for our 18-20th mag targets. Since our proposed targets are in the same (or brighter) visual magnitude range than our past program, we anticipate comparable results. Even though these objects only outburst once in many decades, there were concerns about the (remote) possibility of one of our targets going into outburst. We successfully worked in a mode for our Cycle 13 program where ground-based observations were secured (world-wide) to monitor the sources from 2 weeks to 24 hrs before the start of the observations, once HST had scheduled them in a normal scheduling sequence. No outbursts occurred, but if they had, the observation would have been canceled to ensure the detector safety. Due to the world-wide access of the AAVSO, we anticipate a similar network of participation. Once the observations are scheduled, we will be attempting to coordinate observations of the optical pulsations in order to make the optimum match of the amplitudes between optical and UV. HOT STARS 12 false 0.0 0.0 false false false false false AVAILABLE STAR INTERACTING BINARY ZZ CETI STAR This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 02 29 29.6000 +40 02 41.00 J2000 STAR INTERACTING BINARY ZZ CETI STAR J2000 12 55 10.6500 +26 42 26.30 J2000 STAR INTERACTING BINARY ZZ CETI STAR SDSS object J2000 07 45 31.9200 +45 38 29.50 J2000 STAR INTERACTING BINARY ZZ CETI STAR SDSS object J2000 09 19 45.1100 +08 57 10.00 J2000 STAR INTERACTING BINARY ZZ CETI STAR SDSS object J2000 13 39 41.1200 +48 47 27.40 J2000 STAR INTERACTING BINARY ZZ CETI STAR SDSS object J2000 15 14 13.7200 +45 49 11.80 J2000 ACS/SBC Spectroscopic No No PR110L ACS/SBC Spectroscopic No No PR110L ACS/SBC Spectroscopic No No PR110L ACS/SBC Spectroscopic No No PR110L ACS/SBC Spectroscopic No No PR110L ACS/SBC Spectroscopic No No PR110L We will be using ground-monitoring to ensure this object is at quiescence. AFTER BY requirement needed to verify the brightness of the target using ground observations. Also, uplink opportunities are needed in the ~2 orbit interval to clear the NSSC-I Event Flag 2 and allow high-voltage turn-on, if the target is determined to be safe. (Tic-Visit :proposal-id 11163 :visit-id "01" :proposal-version -1 :trans-version "20070325" :date "04-May-2007 14:23:23.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 2575152 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11163 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11163 :visit-id "01" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2771 :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 3169 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "01" :orbit-number 2 :pcs-time 355 :si-vis-utilization 2800 :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 3169 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "01" :orbit-number 3 :pcs-time 355 :si-vis-utilization 2800 :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 3169 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "01" :orbit-number 4 :pcs-time 355 :si-vis-utilization 2800 :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 3169 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "01" :orbit-number 5 :pcs-time 355 :si-vis-utilization 2800 :al-overhead-at-end 0 :internal-dur-at-end 362 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3169 :pcs-gap 0 ) false 5 0 Set NSSC-I Event Flag 2 to allow high-voltage turn-on. Insert SQL for qasi_states ACS start/end = WFHROPER, DOOR start/end = OPEN, HCOR start/end = HOLD, LAMP start/end = HOLD, and WCOR start/end = HOLD. We will be using ground-monitoring to ensure this object is at quiescence. AFTER BY requirement needed to verify the brightness of the target using ground observations. Also, uplink opportunities are needed in the ~2 orbit interval to clear the NSSC-I Event Flag 2 and allow high-voltage turn-on, if the target is determined to be safe. (Tic-Visit :proposal-id 11163 :visit-id "02" :proposal-version -1 :trans-version "20070325" :date "04-May-2007 14:24:57.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 2501040 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11163 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11163 :visit-id "02" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2782 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "02" :orbit-number 2 :pcs-time 355 :si-vis-utilization 2727 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "02" :orbit-number 3 :pcs-time 355 :si-vis-utilization 2727 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "02" :orbit-number 4 :pcs-time 355 :si-vis-utilization 2727 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "02" :orbit-number 5 :pcs-time 355 :si-vis-utilization 2727 :al-overhead-at-end 0 :internal-dur-at-end 362 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) false 5 0 Set NSSC-I Event Flag 2 to allow high-voltage turn-on. Insert SQL for qasi_states ACS start/end = WFHROPER, DOOR start/end = OPEN, HCOR start/end = HOLD, LAMP start/end = HOLD, and WCOR start/end = HOLD. We will be using ground-monitoring to ensure this object is at quiescence. AFTER BY requirement needed to verify the brightness of the target using ground observations. Also, uplink opportunities are needed in the ~2 orbit interval to clear the NSSC-I Event Flag 2 and allow high-voltage turn-on, if the target is determined to be safe. (Tic-Visit :proposal-id 11163 :visit-id "03" :proposal-version -1 :trans-version "20070709" :date "02-Oct-2007 14:02:12.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "28" :si-bright-earth-limb-angle 20.0 :data-volume 2575152 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11163 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11163 :visit-id "03" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2822 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "03" :orbit-number 2 :pcs-time 355 :si-vis-utilization 2828 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "03" :orbit-number 3 :pcs-time 355 :si-vis-utilization 2828 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "03" :orbit-number 4 :pcs-time 355 :si-vis-utilization 2828 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "03" :orbit-number 5 :pcs-time 355 :si-vis-utilization 2828 :al-overhead-at-end 0 :internal-dur-at-end 372 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3183 :pcs-gap 0 ) false 5 0 Set NSSC-I Event Flag 2 to allow high-voltage turn-on. Insert SQL for qasi_states ACS start/end = WFHROPER, DOOR start/end = OPEN, HCOR start/end = HOLD, LAMP start/end = HOLD, and WCOR start/end = HOLD. We will be using ground-monitoring to ensure this object is at quiescence. AFTER BY requirement needed to verify the brightness of the target using ground observations. Also, uplink opportunities are needed in the ~2 orbit interval to clear the NSSC-I Event Flag 2 and allow high-voltage turn-on, if the target is determined to be safe. (Tic-Visit :proposal-id 11163 :visit-id "04" :proposal-version -1 :trans-version "20070709" :date "24-Oct-2007 06:53:18.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "28" :si-bright-earth-limb-angle 20.0 :data-volume 2501040 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11163 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11163 :visit-id "04" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2786 :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 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "04" :orbit-number 2 :pcs-time 355 :si-vis-utilization 2727 :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 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "04" :orbit-number 3 :pcs-time 355 :si-vis-utilization 2727 :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 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "04" :orbit-number 4 :pcs-time 355 :si-vis-utilization 2727 :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 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "04" :orbit-number 5 :pcs-time 355 :si-vis-utilization 2727 :al-overhead-at-end 0 :internal-dur-at-end 372 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) false 5 1 Set NSSC-I Event Flag 2 to allow high-voltage turn-on. Insert SQL for qasi_states ACS start/end = WFHROPER, DOOR start/end = OPEN, HCOR start/end = HOLD, LAMP start/end = HOLD, and WCOR start/end = HOLD. We will be using ground-monitoring to ensure this object is at quiescence. AFTER BY requirement needed to verify the brightness of the target using ground observations. Also, uplink opportunities are needed in the ~2 orbit interval to clear the NSSC-I Event Flag 2 and allow high-voltage turn-on, if the target is determined to be safe. (Tic-Visit :proposal-id 11163 :visit-id "05" :proposal-version -1 :trans-version "20070325" :date "04-May-2007 14:29:44.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 2575152 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11163 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11163 :visit-id "05" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2782 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "05" :orbit-number 2 :pcs-time 355 :si-vis-utilization 2828 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "05" :orbit-number 3 :pcs-time 355 :si-vis-utilization 2828 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "05" :orbit-number 4 :pcs-time 355 :si-vis-utilization 2828 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "05" :orbit-number 5 :pcs-time 355 :si-vis-utilization 2828 :al-overhead-at-end 0 :internal-dur-at-end 362 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3183 :pcs-gap 0 ) false 5 0 Set NSSC-I Event Flag 2 to allow high-voltage turn-on. Insert SQL for qasi_states ACS start/end = WFHROPER, DOOR start/end = OPEN, HCOR start/end = HOLD, LAMP start/end = HOLD, and WCOR start/end = HOLD. We will be using ground-monitoring to ensure this object is at quiescence. AFTER BY requirement needed to verify the brightness of the target using ground observations. Also, uplink opportunities are needed in the ~2 orbit interval to clear the NSSC-I Event Flag 2 and allow high-voltage turn-on, if the target is determined to be safe. (Tic-Visit :proposal-id 11163 :visit-id "06" :proposal-version -1 :trans-version "20070325" :date "04-May-2007 14:31:20.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 2575152 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11163 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11163 :visit-id "06" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2771 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "06" :orbit-number 2 :pcs-time 355 :si-vis-utilization 2800 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "06" :orbit-number 3 :pcs-time 355 :si-vis-utilization 2800 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "06" :orbit-number 4 :pcs-time 355 :si-vis-utilization 2800 :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 3183 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11163 :visit-id "06" :orbit-number 5 :pcs-time 355 :si-vis-utilization 2800 :al-overhead-at-end 0 :internal-dur-at-end 362 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3183 :pcs-gap 0 ) false 5 0 Set NSSC-I Event Flag 2 to allow high-voltage turn-on. Insert SQL for qasi_states ACS start/end = WFHROPER, DOOR start/end = OPEN, HCOR start/end = HOLD, LAMP start/end = HOLD, and WCOR start/end = HOLD. This Visit sets the NSSC-I Event Flag 2 that disables the high-voltage turn-on. The high-voltage will be enabled, to allow SBC observations in the corresponding Visit, using real-time commanding if the target is determined to be safe. false -1 -1 Set NSSC-I Event Flag 2 to prevent high-voltage turn-on. Insert SQL to ensure that the SBC is off when the flag is set, and for qasi_states ACS start/end = WFHROPER, DOOR start/end=OPEN, HCOR start/end=HOLD,LAMP start/end=HOLD, and WCOR start/end=HOLD. This Visit sets the NSSC-I Event Flag 2 that disables the high-voltage turn-on. The high-voltage will be enabled, to allow SBC observations in the corresponding Visit, using real-time commanding if the target is determined to be safe. false -1 -1 Set NSSC-I Event Flag 2 to prevent high-voltage turn-on. Insert SQL to ensure that the SBC is off when the flag is set, and for qasi_states ACS start/end = WFHROPER, DOOR start/end=OPEN, HCOR start/end=HOLD,LAMP start/end=HOLD, and WCOR start/end=HOLD. This Visit sets the NSSC-I Event Flag 2 that disables the high-voltage turn-on. The high-voltage will be enabled, to allow SBC observations in the corresponding Visit, using real-time commanding if the target is determined to be safe. false -1 -1 Set NSSC-I Event Flag 2 to prevent high-voltage turn-on. Insert SQL to ensure that the SBC is off when the flag is set, and for qasi_states ACS start/end = WFHROPER, DOOR start/end=OPEN, HCOR start/end=HOLD,LAMP start/end=HOLD, and WCOR start/end=HOLD. This Visit sets the NSSC-I Event Flag 2 that disables the high-voltage turn-on. The high-voltage will be enabled, to allow SBC observations in the corresponding Visit, using real-time commanding if the target is determined to be safe. false -1 -1 Set NSSC-I Event Flag 2 to prevent high-voltage turn-on. Insert SQL to ensure that the SBC is off when the flag is set, and for qasi_states ACS start/end = WFHROPER, DOOR start/end=OPEN, HCOR start/end=HOLD,LAMP start/end=HOLD, and WCOR start/end=HOLD. This Visit sets the NSSC-I Event Flag 2 that disables the high-voltage turn-on. The high-voltage will be enabled, to allow SBC observations in the corresponding Visit, using real-time commanding if the target is determined to be safe. false -1 -1 Set NSSC-I Event Flag 2 to prevent high-voltage turn-on. Insert SQL to ensure that the SBC is off when the flag is set, and for qasi_states ACS start/end = WFHROPER, DOOR start/end=OPEN, HCOR start/end=HOLD,LAMP start/end=HOLD, and WCOR start/end=HOLD. This Visit sets the NSSC-I Event Flag 2 that disables the high-voltage turn-on. The high-voltage will be enabled, to allow SBC observations in the corresponding Visit, using real-time commanding if the target is determined to be safe. false -1 -1 Set NSSC-I Event Flag 2 to prevent high-voltage turn-on. Insert SQL to ensure that the SBC is off when the flag is set, and for qasi_states ACS start/end = WFHROPER, DOOR start/end=OPEN, HCOR start/end=HOLD,LAMP start/end=HOLD, and WCOR start/end=HOLD.