0Assigned ID: 3813
----- Attempting Submission 1 (Thu Oct 13 20:47:28 GMT 2022) -----Unsupported characters were found in Observing Description and replaced with |*|
ORBITAL VISIBILITY OVERRUN
ORBITAL VISIBILITY OVERRUN
ORBITAL VISIBILITY OVERRUN
ORBITAL VISIBILITY OVERRUNThis is the initial submission. This observation has solar exclusion fast approaching on Jan 7 so we are ready to make adjustments for schedulability. Although the asteroid pair would fit within the 2k subarray we are interested in the area around them too, so would be very reluctant to move away from full-frame WFC3 imaging. But then to get 5 x 348s exposures in each orbit I had to specify SCHED=30 which may not be feasible. The orient range is available in the first week of January and is included to help visualize the pointing in Aladin (it could be removed). A gap dither is included between the orbits, and we may add another offset to optimize the placement of the two nuclei within the frame, whicl avoiding the chip gaps. -- Max Mutchler64880825----- Attempting Submission 1 (Fri Dec 02 18:30:06 GMT 2022) -----Slight overrrun with SCHED=30 will be discussed with our Program Coordinator.A New Asteroid PairMain belt asteroids 2010 UM26 and 2010 RN221 share almost identical orbital elements and currently appear as comoving objects only 35 arcsec apart in the plane of the sky. They are products of the recent breakup of a parent body, but the nature of this body and the details of the breakup are unknown. Breakup through rotational instability is suspected based on the very small (cm/sec) separation velocity, and this process is increasingly recognised as of particular importance in the evolution and disintegration of small asteroids. With a separation age measured in decades rather than millions of years as for other asteroid pairs, this pair presents the opportunity to study breakup in its earliest stages. We propose deep, high resolution imaging with HST and WFC3 to examine 1) the number and distribution of fragments and 2) the debris sheet expected from rotational instability. These observations will set the baseline appearance and provide a reference for the sensible planning of additional observations in future cycles.We propose deep imaging observations with WFC3 and the F350LP filter. The latter filter has an extraordinarily wide bandpass that provides maximum sensitivity to faint objects and has become the filter of choice for numerous solar system programs where deep imaging is needed. The main penalty of using this broad filter is that the color term is significant at the 0.1 magnitude level, but this is not a hindrance for the proposed observations. We request 4 HST orbits to accumulate a deep image, and will obtain 6 images each of 300 s duration in each orbit, dithered to provide protection from CCD defects. For this measurement, the greater the amount of on-source time the better. However, in realistic view of the scarcity of Hubble time, we here request a minimum of 4 orbits in order to conduct the observations. This request has two motivations. First, we need the deepest images to detect faint (small) fragments in this system and so to define the size distribution. As in 331P, we expect that the faintest objects are numerically dominant, putting a high premium on deep data. The WFC3 exposure time calculator indicates that in 4 orbits with this exposure and filter, we will reach a 5 limiting magnitude V = 26.8. At this limit, the corresponding object diameter is 40 m (for the same 0.24 albedo). Bodies this small contain 104 of the mass contained in 2010 UM26. This sensitivity calculation neglects any noise contribution from diffuse light in a background particle trail, but there is no meaningful way to estimate the trail brightness or the noise contribution in detail. However, observations of comets and other solar system bodies with particle trails suggest that the loss due to elevated background signal might be a few tenths of a magnitude in the detection of embedded point sources. Second, a major problem in deep solar system imaging is set by background sources which are trailed across the images as a result of parallactic motion of the target. Images secured in a single orbit are often insufficient to remove trailed background objects but better suppression is possible when combining data from several orbits having completely different stellar and galactic backgrounds. Therefore, combining data from 4 orbits will give us a deeper limiting magnitude and a better suppression of background structure due to trailed objects. The request for 4 orbits is further buttressed by examination of archival data from 331P (GO 14192, 14475, 14798, and 15360) where 4 orbits with the best trailed galaxy elimination schemes were needed to reveal a majority of the faint fragments and to define the trail surface brightness profile. The two asteroids 2010 UM26 and 2010 RN221 are co-moving objects separated by about 35 in the plane of the sky, which fit neatly within the 210 field of view of WFC3. The distribution of smaller (fainter) fragments is unknown, however, and the fragment train could be longer. We will position the asteroid pair so as to obtain maximum visibility along the UM26 - RN221 line, which is closely approximated by the projected orbital line as cal- culated from JPL Horizons. The ephemeris uncertainties of 2010 UM26 and 2010 RN221 are <1 and therefore of no consequence for the planning of these observations. We request observations as soon as possible before UT 2023 January 7, after which the elon- gation of the target will fall below the 55 limit for observations with HST. After January 7, the elongation will remain too small for HST until 2023 September 18. Observations in Cycle 31 will be possible but with a considerably less favorable observing geometry. For example, the heliocentric, rH, and geocentric, distances, will change from rH, = 1.750, 2.114 AU on UT 2023 January 7 to rH, = 2.513, 2.943 AU on UT 2023 September 18, corresponding to a m = 1.50 magnitude (factor of 4.0) loss in brightness. Observations at later dates would require integration times longer by roughly 42 = 16, or more, than those secured before 2023 January 7, in order to reach the same absolute sensitivity to faint components. The Earth (and HST) will cross the orbit plane on UT November 17, but will remain within 1.4 of the orbit plane until the observing window closes on January 7. Observations from small out-of-plane angles confer an advantage in the detection of low surface brightness, low velocity material, which remains close to the orbit plane of the source body.PI Jewitt is experienced in the study of solar system bodies with HST and other telescopes. CoI Kim is an expert in the modeling of dust dynamics, needed to interpret the trail dynamics. CoI Li is experienced in digital imaging analysis. CoI Mutchler is an expert in matching the capabilities of HST/WFC3 to the scientific study of challenging non-sidereal targets.Solar System Astronomy3falsefalsefalsefalsefalsetruefalseSUPPORTEDSOLAR SYSTEMASTEROIDasteroid pairTYPE=ASTEROID,A=2.576600452914094,E=0.3261426763028916,I=3.860178858863982
,O=235.388737551938,W=119.1361691836958,M=54.50043230195645,EQUINOX=J2000,EPOCH=12-APR-2015:00:00:00,EpochTimeScale=TDBEARTHWFC3/UVISImagingNoNoF350LPUsing ephemeris for target 17288-01-2010UM26ephemeris data for target 17288-01-2010UM26 does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 22.213 to 24.182. ephemeris interval: 22.334 to 24.336Timing link suitability includes constraints ([Sequence (01 02 03 04) within 0.5 days])Hst Same orient constraint links visits (01 02 03 04)The scheduling data was generated by CASM 30.3.CASM was run in Phase II mode.(Tic-Visit
:proposal-id 17288
:visit-id "01"
:proposal-version -1
:trans-version "20220630"
:date "02-Dec-2022 13:19:14.0"
:trans-errors '(:WARNINGS 1 :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 1443744
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 17288
:visit-id "01"
:obset-id "01"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 17288
:visit-id "01"
:orbit-number 1
:pcs-time 393
:si-vis-utilization 2421
:al-overhead-at-end 0
:internal-dur-at-end 668
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 2782
:pcs-gap 0
)false11Using ephemeris for target 17288-02-2010UM26ephemeris data for target 17288-02-2010UM26 does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 22.213 to 24.182. ephemeris interval: 22.334 to 24.336Timing link suitability includes constraints ([Sequence (01 02 03 04) within 0.5 days])Hst Same orient constraint links visits (01 02 03 04)The scheduling data was generated by CASM 30.3.CASM was run in Phase II mode.(Tic-Visit
:proposal-id 17288
:visit-id "02"
:proposal-version -1
:trans-version "20220630"
:date "02-Dec-2022 13:19:15.0"
:trans-errors '(:WARNINGS 1 :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 1443744
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 17288
:visit-id "02"
:obset-id "02"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 17288
:visit-id "02"
:orbit-number 1
:pcs-time 393
:si-vis-utilization 2421
:al-overhead-at-end 0
:internal-dur-at-end 668
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 2782
:pcs-gap 0
)false11Using ephemeris for target 17288-03-2010UM26ephemeris data for target 17288-03-2010UM26 does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 22.213 to 24.182. ephemeris interval: 22.334 to 24.336Timing link suitability includes constraints ([Sequence (01 02 03 04) within 0.5 days])Hst Same orient constraint links visits (01 02 03 04)The scheduling data was generated by CASM 30.3.CASM was run in Phase II mode.(Tic-Visit
:proposal-id 17288
:visit-id "03"
:proposal-version -1
:trans-version "20220630"
:date "02-Dec-2022 13:19:15.0"
:trans-errors '(:WARNINGS 1 :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 1443744
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 17288
:visit-id "03"
:obset-id "03"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 17288
:visit-id "03"
:orbit-number 1
:pcs-time 393
:si-vis-utilization 2421
:al-overhead-at-end 0
:internal-dur-at-end 668
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 2782
:pcs-gap 0
)false11Using ephemeris for target 17288-04-2010UM26ephemeris data for target 17288-04-2010UM26 does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 22.213 to 24.182. ephemeris interval: 22.334 to 24.336Timing link suitability includes constraints ([Sequence (01 02 03 04) within 0.5 days])Hst Same orient constraint links visits (01 02 03 04)The scheduling data was generated by CASM 30.3.CASM was run in Phase II mode.(Tic-Visit
:proposal-id 17288
:visit-id "04"
:proposal-version -1
:trans-version "20220630"
:date "02-Dec-2022 13:19:16.0"
:trans-errors '(:WARNINGS 1 :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 1443744
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 17288
:visit-id "04"
:obset-id "04"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 17288
:visit-id "04"
:orbit-number 1
:pcs-time 393
:si-vis-utilization 2421
:al-overhead-at-end 0
:internal-dur-at-end 668
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 2782
:pcs-gap 0
)false11