This is the revised version of 10628 with a new ORIENT value of 260. Alison Vick reported this morning that the previous ORIENT=240 did not have guide-stars. ----- Submission 1 (Fri Apr 29 14:58:05 GMT 2005) ----- ----- Submission 2 (Mon May 02 16:09:09 GMT 2005) ----- Assigned ID: 9 ----- Submission 1 (Wed Jan 12 17:31:48 GMT 2005) ----- Determining the Lifetime of Planetary Nebula Knots from Observations of the Core of the Helix Nebula. Knots within the Planetary Nebulae (PN) are ubiquitous components and form at the interface of the expanding ionized zone and the surrounding dusty and molecule-rich neutral layers. About half of the total mass ejected by the precursor star becomes trappped in the Knots, which will join the Interstellar Medium (ISM) within a few tens of thousands of years. If they survive, they may be the source of the micro-structures that appear to be common in the ISM, a result that would be important in understanding the exchange of matter between stars and the ISM. We propose observations that will characterize the Knots over a wider ionization range and ages than has been done before, which should yield the best model for the Knots and therefore the best prediction of their fates. Knots are not seen within a well defined distance from the central star. We don't know if this is because they are being destroyed by photoevaporation (since the inner Knots would be the youngest), an important factor in our modeling. However, the inner core of the Helix Nebula has not been imaged in the HeII emission that dominates the region. We propose eight orbits of observations that will search the inner core of the Helix for undetected knots using the WFPC2 HeII F469N filter and the ACS-WFC F502N filter that isolates [OIII] emission. Our WFPC2 pointing will also allow imaging the best studied knot in HeII, giving us the best possible data for that Knot. These combined results will be modeled with the new Hydro-Cloudy code, allowing us to determine if they will survive the PN stage and become components of the ISM. At no additional cost of observing time we will be able to derive a calibration of the WFPC2 F469N filter, to make unprecedented quality parallel images in molecular hydrogen, and to extended the coverage of high resolution emission-line images of the Helix Nebula.
We will make eight orbits of observations using four close pointings within the same object, the Helix Nebula-NGC 7293.The primary instrument will be the WFPC2, where all of the observations will be made using the F469N filter, a new pointing will be made for each orbit. Coordinated parallel observations will be made with at each WFPC2 setting. The NIC3 observations will be made with the F212N and F215N filters at each pointing. The ACS observations will be made with the F502N and F658N filters, alternating with the pointings.Orientation is very important in this program. ORIENT=240 is the best value for the Two-Gyro-Mode. If this value cannot be scheduled, I would want to substitute new pointing coordinates for the ORIENT value that is available. In the event that these observations are scheduled early in Cycle 14 and the Three-Gyro-Mode is available, I would want to use a new ORIENT value (060) and to using a different set of pointings. Please keep me apprised of this possibility. ISM AND CIRCUMSTELLAR MATTER 12 false 0 0.0 false 0 false false false false SUPPORTED ISM PLANETARY NEBULA Coordinates taken from an earlier HST WFPC2 image. V magnitude is a dummy as there are no bright stars in the FOV. Total flux from object is log F(Hb)=-9.35 (ergs/cmsq/sec J2000 22 29 38.3500 -20 50 13.60 J2000 ISM PLANETARY NEBULA Coordinates taken from an earlier HST WFPC2 image. V magnitude is a dummy as there are no bright stars in the FOV. Total flux from object is log F(Hb)=-9.35 (ergs/cmsq/sec 00 00 0.0000 +00 00 0.00 J2000 ISM PLANETARY NEBULA Coordinates taken from an earlier HST WFPC2 image. V magnitude is a dummy as there are no bright stars in the FOV. Total flux from object is log F(Hb)=-9.35 (ergs/cmsq/sec 00 00 0.0000 +00 00 0.00 J2000 ISM PLANETARY NEBULA Coordinates taken from an earlier HST WFPC2 image. V magnitude is a dummy as there are no bright stars in the FOV. Total flux from object is log F(Hb)=-9.35 (ergs/cmsq/sec 00 00 0.0000 +00 00 0.00 J2000 WFPC2 Imaging No F469N ACS/WFC Imaging No No F502N ACS/WFC Imaging No No F660N ACS/WFC Imaging No No F658N NIC3 Imaging No No F212N NIC3 Imaging No No F215N WFPC2 Imaging No F656N WFPC2 Imaging No F658N NIC3 Imaging No No F212N NIC3 Imaging No No F215N (Tic-Visit :proposal-id 10628 :visit-id "01" :proposal-version -1 :trans-version "20050323" :date "02-May-2005 10:23:33.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "23" :si-bright-earth-limb-angle 20.0 :data-volume 2146496 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 10628 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 10628 :visit-id "01" :orbit-number 1 :pcs-time 367 :si-vis-utilization 2880 :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 3258 :pcs-gap 0 ) (Tic-Orbit :proposal-id 10628 :visit-id "01" :orbit-number 2 :pcs-time 367 :si-vis-utilization 2891 :al-overhead-at-end 13 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3258 :pcs-gap 0 ) (Tic-Orbit :proposal-id 10628 :visit-id "01" :orbit-number 3 :pcs-time 367 :si-vis-utilization 2891 :al-overhead-at-end 16 :internal-dur-at-end 471 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3258 :pcs-gap 0 ) false 3 0 (Tic-Visit :proposal-id 10628 :visit-id "02" :proposal-version -1 :trans-version "20050323" :date "02-May-2005 10:25:20.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "23" :si-bright-earth-limb-angle 20.0 :data-volume 2146496 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 10628 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 10628 :visit-id "02" :orbit-number 1 :pcs-time 367 :si-vis-utilization 2880 :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 3258 :pcs-gap 0 ) (Tic-Orbit :proposal-id 10628 :visit-id "02" :orbit-number 2 :pcs-time 367 :si-vis-utilization 2891 :al-overhead-at-end 13 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3258 :pcs-gap 0 ) (Tic-Orbit :proposal-id 10628 :visit-id "02" :orbit-number 3 :pcs-time 367 :si-vis-utilization 2891 :al-overhead-at-end 13 :internal-dur-at-end 471 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3258 :pcs-gap 0 ) true 3 0 (Tic-Visit :proposal-id 10628 :visit-id "03" :proposal-version -1 :trans-version "20050323" :date "02-May-2005 10:25:53.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "23" :si-bright-earth-limb-angle 20.0 :data-volume 1431008 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 10628 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 10628 :visit-id "03" :orbit-number 1 :pcs-time 367 :si-vis-utilization 2880 :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 3258 :pcs-gap 0 ) (Tic-Orbit :proposal-id 10628 :visit-id "03" :orbit-number 2 :pcs-time 367 :si-vis-utilization 2891 :al-overhead-at-end 14 :internal-dur-at-end 409 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3258 :pcs-gap 0 ) true 2 0