0 Assigned ID: 7420 ----- Attempting Submission 1 (Thu Apr 16 15:20:36 GMT 2026) ----- HST Phase I Proposal 7420 successfully submitted. Receipt: # 7420-1 ----- Attempting Submission 2 (Thu Apr 16 17:49:07 GMT 2026) ----- HST Phase I Proposal 7420 successfully submitted. Receipt: # 7420-2 ----- Attempting Submission 3 (Thu Apr 16 17:54:40 GMT 2026) ----- Could not connect to APT Status Server Exposure time can be shortened slightly if needed for schedulability 1852682748 ----- Attempting Submission 1 (Thu Aug 13 23:50:01 GMT 2026) ----- unknown server or database connection problem - warning everything seems to be working so not sure what the problem might be Testing the Collision-Color-Satellite Connection in the Trojans Large asteroids with small satellites are frequently associated with collisional families. Among the Trojans the Eurybates family is the largest of only six known families. (3548) Eurybates, the largest member of this family, is the first Trojan target of the Lucy Discovery mission. Eurybates also has a satellite and, intriguingly, is a spectrally neutral C-type in a population where more than 90% are redder P- or D-type objects. C-type collisional family asteroids with satellites are known in the Main Belt where C-types are common. But with just a single example of the apparent connection between collisions, satellite formation and unusual color in the Trojans, it is difficult to reach a conclusion about the causal nature of these correlated properties. However, there are two ideal candidates for testing this correlation - the C-type Trojan asteroids (4709) Ennomos and (9799) Thronium - both have recently been shown to have collisional families and both are less-red than the vast majority of Trojans. By using HST to search for satellites, we propose to test the hypothesis that all three properties are causally related. If satellites are found, the likelihood of chance correlation is significantly reduced. Identifying the processes at work as "normal" will enhance the value of the upcoming Lucy encounter with Eurybates by allowing discoveries in that system to be extrapolated to other objects and populations. If no satellites are identified, we will tighten constraints on the outcomes and subsequent evolution of collisional processing in the Trojans. This proposal will execute two visits each to two Trojan asteroid that are possible analogs to Eurybates. Both are largest members of collisional families and both are unusually neutral in color, like Eurybates. Each visit will have six exposures in the F350LP filter to go as deep as possible in order to search for satellites that might have resulted from the family forming collision. The two visits for each object will be separated by a minimum time calculated to give even very wide possible satellites enough time to have moved at least 1/4 of an orbit to improve the chance of detection at at least one epoch. A line dither pattern will be used with an offset between each iteration of the dither to achieve sub pixel dithering. The PI has more than three decades of experience with HST and has successfully completed many previous programs and has a substantial track record of HST-related publication. The co-I is also highly experienced with both HST and JWST and has special expertise in HST data reduction and analysis. All required tools and expertise necessary to successfully complete the proposed work are in place. Solar System Astronomy 6 false false false false false false false SUPPORTED SOLAR SYSTEM ASTEROID Trojan Asteroid (4709) Ennomos TYPE=ASTEROID,A=5.274586528852086,E=0.02264257597954345,I=25.41386995274401,O=253.0588450054122,W=83.67865706597865,M=92.72663675193036,EQUINOX=J2000,EPOCH=09-JUN-2026:00:00:00,EpochTimeScale=TDB EARTH SOLAR SYSTEM ASTEROID Trojan Asteroid (9799) Thronium TYPE=ASTEROID,A=5.191110558168659,E=0.04685583179040113,I=30.51270344780228,O=259.5593137497432,W=115.3240300704947,M=159.6742252254411,EQUINOX=J2000,EPOCH=09-JUN-2026:00:00:00,EpochTimeScale=TDB EARTH WFC3/UVIS Imaging No No F350LP WFC3/UVIS Imaging No No F350LP WFC3/UVIS Imaging No No F350LP WFC3/UVIS Imaging No No F350LP POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 1 false /private/var/folders/w0/gxr42v9n52d71z2s3jxvdk6m0000gq/T/OPVisit15985726390100426193.xml Timing link suitability includes constraints ([02 After 01 by 12.0 to 120.0 days]) The scheduling data was generated by CASM 34.2. 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(Tic-Visit :proposal-id 18364 :visit-id "11" :proposal-version -1 :trans-version "20260618" :date "13-Aug-2026 17:34:26.0" :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 27472 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18364 :visit-id "11" :obset-id "11" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18364 :visit-id "11" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2511 :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 2979 :pcs-gap 0 ) true 1 0 /private/var/folders/w0/gxr42v9n52d71z2s3jxvdk6m0000gq/T/OPVisit18341476513209188521.xml Timing link suitability includes constraints ([12 After 11 by 20.0 to 120.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. 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