0 Assigned ID: 1932 ----- Attempting Submission 1 (Fri Apr 09 14:34:30 GMT 2021) ----- FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser Edited the BETWEENs for visit 3 to avoid times when 288P should not be observed due to the proximity of bright background stars. These now cover 2 weeks for increased scheduling flexibility. A new target (288P-B) has been defined for V3 (compared to V1+V2), It is the same asteroid, but reflects the updated JPL ephemeris. 1286877295 Your proposal could not be saved. Submission aborted. Your proposal could not be saved. Submission aborted. ----- Attempting Submission 1 (Fri Jul 23 07:56:45 GMT 2021) ----- ----- Attempting Submission 2 (Sat Jul 09 08:15:54 GMT 2022) ----- ----- Attempting Submission 3 (Thu Sep 01 19:30:07 GMT 2022) ----- HST Phase II Proposal 16993 successfully submitted. Receipt: # 16993-3 ----- Attempting Submission 4 (Thu Sep 01 20:25:28 GMT 2022) ----- ----- Attempting Submission 5 (Tue Nov 01 15:11:57 GMT 2022) ----- When running the ETC for the actual zodiacal light background on Nov-03 (WFC3UVIS.im.1812541, used as reference date for all three visits), the calculated background is 18 electrons, which is only slightly below the recommended 20 electrons. We expect that the true background will be further elevated due to residual dust near the object, and therefore assume that CTE will be acceptable. The binary asteroid 288P is unusual both for its sublimation-driven activity and for its peculiar mutual orbit combining similarly-sized components with a wide separation and high eccentricity. The second half if 2022 will witness the 288P system emerging from its second perihelion passage after the binary nature was discovered. We here seek to verify the possibility indicated by earlier HST observations that the mutual orbit was perturbed by an outgassing-induced torque during the 2016/17 perihelion passage. If confirmed, the activity could have led to the unusually wide semimajor axis that cannot be achieved directly from rotational fission. In addition we seek to consolidate the identity of the active component(s) to find out if the activity is a direct consequence of the splitting event leading to binary formation. We also aim to constrain the size of the largest dust particles emitted from the active component(s) that is diagnostic of the strength of sublimation and the potential role played by fast rotation in lifting the dust. Finally, we seek to understand whether the level of activity is constant between apparitions, or if a trend can be identified that would indicate the evolution of exposed ice on main belt asteroids with time. We request five orbits of HST/WFC3 time to be scheduled at roughly 4 week intervals between August and December 2022. These data will allow us to measure the brightness and separations of the components and the evolution of dust lingering from the perihelion passage in winter 2021/22. Only HST is able to spatially resolve the components (max. separation 0.1 arcsec) and central dust cloud of this faint (V=22mag) target. The purpose of this proposal is to observe how activity decreases and ends as the binary main-belt comet 288P moves out from perihelion in the second half of 2022. We plan to observe 288P in 4-weeks intervals between mid-August and early December. Hence two of these 1-orbit visits fall into Cycle 29 and three into Cycle 30. This phase 2 proposal is for the three Cycle 30 visits only. The visits should be carried out around 2022 October 08, November 05, and December 03, with a flexibility of 1 week. We expect a target brightness of V=22.5 mag, depending on time. In each orbit, we will take 8 exposures of 239s using the C512C subarray of WFC3 and perform a 2-point dither pattern to mitigate hot pixels and cosmic ray hits, obtaining 4 exposures at each dither point. This provides a total exposure time of 1912 s = 32 min. The ephemeris is known with uncertainty <1arcsec, such that there is no risk of missing the target even using the C512C sub-array. We will use the wide bandpass filter F606W for an optimum trade-off between sensitivity and highest resolution, and maximum compatibility with data from earlier epochs. The target will be at solar elongations between 105 and 175deg. Jessica Agarwal previously analyzed HST data on active asteroids to place constraints on the dust ejection process from the dust dynamics and photometry. She is the PI of several HST programs that lead to the discovery and further analysis of the unusual binary main-belt comet 288P. She will carry out the PSF fitting to measure the component separations and brightnesses, and fit the orbit. Yoonyoung Kim is an expert in the dynamical modeling of dust moving under the action of gravity, solar radiation pressure and initial velocity distribution and will carry out the dust dynamical modelling, David Jewitt has an extensive record of research into the study of small solar system bodies, especially the Kuiper belt objects and the cometary nuclei. In the last decade he has written >20 refereed papers based on Hubble data. He will contribute to the measurement, analysis and interpretation of the data and to writing up the results for publication. Max Mutchler is an expert on Hubble's cameras. He will contribute to the subsampling observing strategy, and special image processing for moving targets. Harold Weaver is a veteran Hubble observer, mostly of comets, with many Hubble-related publications. He will contribute to optimizing the observation strategy and to interpreting the data. Stephen Larson is an experienced investigator of small Solar system bodies and the PI of the Catalina Sky Survey, from which previous HST targets including the outburst of (596) Scheila, P/2013 R3 and 313P were discovered. He will contribute to the data interpretation. Solar System Astronomy 6 false false false false false false false SUPPORTED SOLAR SYSTEM YES ASTEROID Binary main-belt comet TYPE=ASTEROID,A=3.048986186274839,E=0.2010716723979907,I=3.240152574320395 ,O=83.18716341122048,W=281.0201183529284,M=37.18809486522964,EQUINOX=J2000,EPOCH=28-MAY-2017:00:00:00,EpochTimeScale=TDB EARTH SOLAR SYSTEM YES ASTEROID Binary main-belt comet TYPE=ASTEROID,A=3.048895795723726,E=0.2010747670269393,I=3.240200267468515 ,O=83.18689950470417,W=281.0089661495639,M=50.34116073331901,EQUINOX=J2000,EPOCH=07-AUG-2017:00:00:00,EpochTimeScale=TDB EARTH WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F606W POS-TARG DITHER 0.145 LINE false false 2 46.84 WFC3-UVIS-DITHER-LINE 1 false 1667315485560 Using ephemeris for target 16993-01-288P ephemeris data for target 16993-01-288P does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 22.250 to 24.182. ephemeris interval: 22.304 to 24.306 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. /tmp/OPVisit8466396591479875675.xml BETWEENs will be used to avoid times when 288P should not be observed due to the proximity of bright background stars. These need to be updated once the HST orbit for this epoch is known in the JPL/Horizons system. 1665177077000 259.0 (Tic-Visit :proposal-id 16993 :visit-id "01" :proposal-version -1 :trans-version "20220630" :date "01-Nov-2022 16:11:25.0" :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 36624 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16993 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16993 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2388 :al-overhead-at-end 0 :internal-dur-at-end 77 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) true 1 0 When running the ETC for the actual zodiacal light background on Nov-03 (WFC3UVIS.im.1812541, used as reference date for all three visits), the calculated background is 18 electrons, which is only slightly below the recommended 20 electrons. We expect that the true background will be further elevated due to residual dust near the object, and therefore assume that CTE will be acceptable. 1667315488428 Using ephemeris for target 16993-02-288P ephemeris data for target 16993-02-288P does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 22.250 to 24.182. ephemeris interval: 22.304 to 24.306 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. /tmp/OPVisit3252025209227045458.xml BETWEENs will be used to avoid times when 288P should not be observed due to the proximity of bright background stars. These need to be updated once the HST orbit for this epoch is known in the JPL/Horizons system. 1667565145000 267.0 (Tic-Visit :proposal-id 16993 :visit-id "02" :proposal-version -1 :trans-version "20220630" :date "01-Nov-2022 16:11:28.0" :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 36624 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16993 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16993 :visit-id "02" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2388 :al-overhead-at-end 0 :internal-dur-at-end 77 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) true 1 0 When running the ETC for the actual zodiacal light background on Nov-03 (WFC3UVIS.im.1812541, used as reference date for all three visits), the calculated background is 18 electrons, which is only slightly below the recommended 20 electrons. We expect that the true background will be further elevated due to residual dust near the object, and therefore assume that CTE will be acceptable. 1667315416749 Using ephemeris for target 16993-03-288P-B ephemeris data for target 16993-03-288P-B does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 22.250 to 24.182. ephemeris interval: 22.304 to 24.306 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. /home/agarwal/Proposals/HST29_288P/Phase2/OP-cache/288P_deactivation_C30_phase2_221101-v03.xml BETWEENs are defined to avoid times when 288P should not be observed due to the proximity of bright background stars. A new target (288P-B) has been defined compared to V1+V2, to reflect the updated JPL ephemeris. (Tic-Visit :proposal-id 16993 :visit-id "03" :proposal-version -1 :trans-version "20220630" :date "01-Nov-2022 16:10:16.0" :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 36624 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16993 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16993 :visit-id "03" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2388 :al-overhead-at-end 0 :internal-dur-at-end 77 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) true 1 0 When running the ETC for the actual zodiacal light background on Nov-03 (WFC3UVIS.im.1812541, used as reference date for all three visits), the calculated background is 18 electrons, which is only slightly below the recommended 20 electrons. We expect that the true background will be further elevated due to residual dust near the object, and therefore assume that CTE will be acceptable.