Active Asteroid (3200) Phaethon during its unusually close approach to Earth

N/A 76480 Assigned ID: 324 ----- Attempting Submission 1 (Thu Apr 06 22:46:49 GMT 2017) ----- Ephemeris Center: HUBBLE is recommended only when observing a target closer than 3.8 million kilometers. If the target is farther than that, Ephemeris Center: EARTH is recommended. Ephemeris will need to be regenerated. fixed typos -397480445 ----- Attempting Submission 1 (Mon Jul 17 18:51:42 GMT 2017) ----- ----- Attempting Submission 2 (Mon Jul 17 20:23:18 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-2 ----- Attempting Submission 3 (Tue Jul 18 11:08:07 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-3 ----- Attempting Submission 4 (Tue Jul 18 11:18:33 GMT 2017) ----- ----- Attempting Submission 5 (Thu Jul 27 17:54:46 GMT 2017) ----- HST Phase II Proposal 15357 (prop-p2-v2.apt) successfully submitted. Receipt: # 15357-5 ----- Attempting Submission 6 (Thu Jul 27 18:06:19 GMT 2017) ----- ----- Attempting Submission 8 (Sun Jul 30 07:05:06 GMT 2017) ----- ----- Attempting Submission 9 (Wed Aug 02 16:39:28 GMT 2017) ----- ----- Attempting Submission 10 (Tue Aug 08 18:21:12 GMT 2017) ----- ----- Attempting Submission 12 (Mon Aug 14 12:21:01 GMT 2017) ----- ----- Attempting Submission 13 (Mon Aug 14 16:41:53 GMT 2017) ----- ----- Attempting Submission 14 (Wed Nov 01 12:09:46 GMT 2017) ----- ----- Attempting Submission 15 (Mon Nov 06 13:51:49 GMT 2017) ----- ----- Attempting Submission 16 (Mon Nov 06 17:22:49 GMT 2017) ----- Your proposal could not be saved. Submission aborted. ----- Attempting Submission 17 (Thu Nov 16 07:06:07 GMT 2017) ----- ----- Attempting Submission 18 (Thu Nov 16 13:45:02 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-18 ----- Attempting Submission 19 (Thu Nov 16 19:36:51 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-19 ----- Attempting Submission 20 (Thu Nov 16 19:53:34 GMT 2017) ----- ----- Attempting Submission 21 (Fri Nov 17 17:22:07 GMT 2017) ----- ----- Attempting Submission 22 (Mon Nov 20 18:37:21 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-22 ----- Attempting Submission 23 (Mon Nov 20 19:37:07 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-23 ----- Attempting Submission 24 (Mon Nov 20 19:48:43 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-24 ----- Attempting Submission 25 (Mon Nov 20 20:14:50 GMT 2017) ----- ----- Attempting Submission 26 (Tue Nov 21 06:38:58 GMT 2017) ----- ----- Attempting Submission 27 (Tue Nov 21 13:12:11 GMT 2017) ----- ----- Attempting Submission 28 (Tue Nov 21 14:47:22 GMT 2017) ----- ----- Attempting Submission 29 (Tue Nov 21 17:42:18 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-29 ----- Attempting Submission 30 (Tue Nov 21 18:03:49 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-30 ----- Attempting Submission 31 (Tue Nov 21 18:16:55 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-31 ----- Attempting Submission 32 (Tue Nov 21 18:21:59 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-32 ----- Attempting Submission 33 (Tue Nov 21 18:22:31 GMT 2017) ----- ----- Attempting Submission 34 (Mon Nov 27 12:23:46 GMT 2017) ----- HST Phase II Proposal 15357 (15357.apt) successfully submitted. Receipt: # 15357-34 ----- Attempting Submission 35 (Mon Nov 27 12:32:18 GMT 2017) ----- APT cannot calculate ephemeris from the manually inserted orbital elements. I tested the fixed coordinates with Visit Planner which suggested that they are schedulable. The approximate coordinates are given in Proposal Description. Active Asteroid (3200) Phaethon during its unusually close approach to Earth The unusual asteroid and possible dormant comet (3200) Phaethon will pass 0.069 AU (27 lunar distances) from the Earth in Dec 2017, the closest since its discovery in 1983 and also until 2093. Phaethon is classified as an asteroid but has been associated with the strong Geminid meteor shower, implying significant mass loss during its previous orbits of which the mechanism remains poorly understood. We hereby request two HST GO orbits to observe Phaethon with HST/ACS during its flyby in Dec 2017. Our goal is to look for accompanying meter-sized fragments as well as to detect the associated dust (meteoroid) dust trail. The proposed observation will provide valuable information for the origin of Phaethon's mass loss. HST's high angular resolution and sensitivity is critical for achiving the maximum science return from this unprecedented clost approach. The main goal of this program is to search for meter-sized fragments from Phaethon (point sources). The images will also enable search for Phaethon's associated dust trail (extended source) which will be done on a best-effort basis. Orbital elements are derived from an ensemble of synthetic fragments, represented by an artificial object, "Phaethon-clone". The position of Phaethon-clone at the observation window is roughly RA=265 deg, Dec=+55 deg. The probability ellipse is oriented along 27 deg (N=0 deg) and is about 10' wide, 6 deg long. We use pos-targ to offset the two visits; however, the on-sky orientation depends on the orientation of HST focal plane, which is unknown at this point. The pos-targ parameters are subjected to update when the orientation of the HST focal plane is known. In the worst case scenario that the pos-targ are perpendicular to the ellipse axis, the images are still within the probability ellipse and are therefore useful for science. We plan to use 2 orbits to image a total of two positions (each position include its respective dithering) with ACS/WFC, covering a 6'-wide section within the probability ellipse. For each visit, we will take four 545-s exposures, dithering between two points that are 10 pixels apart in both x and y directions, in order to migrate the effects of cosmic rays and comtamination of background star trails. We plan to use Broadband V (F606W) filter in order to derive spectral information of any detected fragments. We set FLASH=3 in order to correct for poor charge transfer efficiency (CTE). The ACS Exposure Time Calculator indicates that a signal-to noise ratio of 4 can be reached in 545 s exposure, assuming a solar-type spectrum point source at V=27.0, corresponding to a 1-m-sized object (assuming a geometric albedo of 0.10 similar to Phaethon). Observations are planned for a 4-hour window near 2017 Dec 14 14:00 UT, the time that the Earth passes the minimum orbit intersection distance (MOID) point of which the fragments near this position are closest (~0.02 au). This position is far from Phaethon itself on the sky plane (more than tens of degrees) due to the geometry caused by the close approach, therefore Phaethon will not be in the images and cannot be used as an acquisition target. Solar System 6 false false false false false false SUPPORTED SOLAR SYSTEM NO OFFSET clone of asteroid (3200) Phaethon TYPE=ASTEROID,A=1.271005134,E=0.88991227,I=22.253726,O=265.22932,W=322.17133,M=304.57093,EQUINOX=J2000,EPOCH=01-NOV-2017:12:00:00,EpochTimeScale=TDB HUBBLE ACS/WFC Imaging No No CLEAR1L 1501398205760 The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 15357 :visit-id "01" :proposal-version -1 :trans-version "20170613" :date "30-Jul-2017 00:03:24.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1136896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15357 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15357 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2728 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3202 :pcs-gap 0 ) false 1 0 1501398209174 The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 15357 :visit-id "02" :proposal-version -1 :trans-version "20170613" :date "30-Jul-2017 00:03:28.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1136896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15357 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15357 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2708 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3202 :pcs-gap 0 ) false 1 0 Spectral Element for both exposures should be CLEAR. Spectral Element for both exposures should be CLEAR. Spectral Element for both exposures should be CLEAR. Spectral Element for both exposures should be CLEAR. 1510938373172 (Tic-Visit :proposal-id 15357 :visit-id "03" :proposal-version -1 :trans-version "20170613" :date "17-Nov-2017 12:06:12.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1136896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15357 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 15357 :visit-id "03" :obset-id "A3" :pcs-mode "GYRO" ) (Tic-Orbit :proposal-id 15357 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2603 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3202 :pcs-gap 0 ) false 1 0 1510938374400 (Tic-Visit :proposal-id 15357 :visit-id "04" :proposal-version -1 :trans-version "20170613" :date "17-Nov-2017 12:06:14.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1136896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15357 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 15357 :visit-id "04" :obset-id "A4" :pcs-mode "GYRO" ) (Tic-Orbit :proposal-id 15357 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2603 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3202 :pcs-gap 0 ) false 1 0 Spectral Element for both exposures should be CLEAR. Spectral Element for both exposures should be CLEAR. Spectral Element for both exposures should be CLEAR. Spectral Element for both exposures should be CLEAR. 1510939294357 (Tic-Visit :proposal-id 15357 :visit-id "13" :proposal-version -1 :trans-version "20170613" :date "17-Nov-2017 12:21:33.0" :trans-errors '(:WARNINGS 18 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 317136 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15357 :visit-id "13" :obset-id "13" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 15357 :visit-id "13" :obset-id "B3" :pcs-mode "GYRO" ) (Tic-Orbit :proposal-id 15357 :visit-id "13" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2525 :al-overhead-at-end 0 :internal-dur-at-end 344 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3202 :pcs-gap 0 ) false 1 0 1511246073475 (Tic-Visit :proposal-id 15357 :visit-id "14" :proposal-version -1 :trans-version "20170613" :date "20-Nov-2017 22:34:31.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 317136 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15357 :visit-id "14" :obset-id "14" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 15357 :visit-id "14" :obset-id "A4" :pcs-mode "GYRO" ) (Tic-Orbit :proposal-id 15357 :visit-id "14" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2475 :al-overhead-at-end 0 :internal-dur-at-end 344 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3202 :pcs-gap 0 ) false 1 0