Cannot find file /Users/charlesschambeau/Desktop/39P-HST-proposal-draft2.pdf 0 Assigned ID: 2656 ----- Attempting Submission 1 (Thu Jan 27 19:48:01 GMT 2022) ----- HST Phase I Proposal 2656 successfully submitted. Receipt: # 2656-1 ----- Attempting Submission 2 (Mon Jan 31 14:44:27 GMT 2022) ----- 2022-07-08: The ephemeris has been updated using an updated orbit from JPL Horizons. -301011619 ----- Attempting Submission 1 (Tue Mar 22 21:31:12 GMT 2022) ----- ----- Attempting Submission 2 (Mon Apr 18 14:52:34 GMT 2022) ----- HST Phase II Proposal 16921 successfully submitted. Receipt: # 16921-2 ----- Attempting Submission 3 (Wed May 18 17:54:48 GMT 2022) ----- ----- Attempting Submission 4 (Fri Jul 08 20:52:43 GMT 2022) ----- Centaurs are the dynamical intermediary between the more distant and thermally pristine Trans-Neptunian Objects (TNOs) with the more processed and active Jupiter-Family Comets (JFCs). In the Centaur region between Neptune and Jupiter the thermal activation of many cosmogonically abundant volatile species occurs driving comae activity. Investigations of these distant comae provide salient data to test models of the solar system's formation. To date thorough Centaur gas comae characterizations are prohibitive due to instrumental sensitivity limitations, however the newly launched James Webb Space Telescope (JWST) will provide the sensitivities necessary to probe Centaur gas comae. Six Centaurs have been approved for JWST Cycle 1 gas comae characterizations [McKay et al. 2021] with additional contemporaneously acquired dust comae observations from other observatories. Of the six JWST Centaur targets 39P/Oterma is predicted to be beyond suitable characterization through ground-based assets during the Cycle 1 NIRSpec observations. We request 2 HST orbits during Cycle 29 (Jul. - Aug. 2022) of WFC3-UVIS imaging to contemporaneously characterize the dust coma of the Centaur 39P/Oterma during scheduled Cycle 1 JWST NIRSpec gas coma characterization. The tight, stable, and well characterized WFC3 PSF in combination with HST's sensitivity to low surface brightness provide the only observational platform currently available to detect and isolate the flux from 39P's dust coma from its nucleus contribution. If a suitable ramp up of comae activity occurs before the scheduled JWST observations we will forgo the HST observations, instead utilizing ground-based assets. We will use two orbits of HST/WFC3 to observe the active Centaur 39P/Oterma's dust coma color and morphology to complement its Cycle 1 JWST NIRSpec IFU Prism gas coma characterization. Due to the variable nature of comae activities it is important to schedule the HST observations as close as possible to the JWST observations to ensure a direct comparison of the time variable coma environment. We will acquire imaging data in WFC3-UVIS in the F475W (SDSS g), F625W (SDSS r), and F775W (SDSS i) filters in order to compare to ensemble studies of comes and Centaurs that commonly use the SDSS gri or BVRI systems. The ephemeris uncertainty of 39P is low (approximately 1 arcsecond) so we choose to use the UVIS-M1K1C-SUB subarray (40 arcsecond FOV) to allow more images to be acquired before buffer dumps. The coma surface brightness during the JWST and HST observations is not know a priori so we base out exposure times to achieve a S/N of > 50 for each of the filters. A total integration of g (20 minutes), r (15 minutes) and i (23 minutes) is planned to achieve the desired S/N. The telescope will be dithered between individual exposures to mitigate effects of bad pixels and for the removal of cosmic rays. The detector pixels will not be binned retaining the native 0.04 arcseconds per pixel resolution. Dr. Charles Schambeau has expertise in HST data reduction for the WFC3-UVIS instrument. He is an expert in analyzing broadband imaging of cometary and Centaur comae and the modeling effort of our program. He has 4 papers published in the past 6 years related to this research. Dr. Adam McKay is the PI of the JWST program and will perform the NIRSpec spectral analysis for gas comae measurements. Additionally, Dr. Eva Lilly (Schunova), Dr. Teddy Kareta, Ms. Olga Harrington-Pinto, and Dr. Yanga Fernandez are experts in the analysis and interpretation of comet and Centaur comae and their activation mechanisms. Solar System Astronomy 3 false false false false false true false SUPPORTED SOLAR SYSTEM YES COMET Comet and Active Centaur 39P/Oterma TYPE=COMET,Q=5.702220310895506,E=0.2293325146529492,I=1.470359413259978 ,O=304.5833580651899,W=88.70051288508857,T=03-APR-2023:21:44:02,TTimeScale=TDB,EQUINOX=J2000,EPOCH=10-SEP-2014:00:00:00,EpochTimeScale=TDB EARTH WFC3/UVIS Imaging No No F475W WFC3/UVIS Imaging No No F625W WFC3/UVIS Imaging No No F775W POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 1 false POS-TARG DITHER 0.135 LINE false false 2 46.84 LINE 2 false 1657313442154 Using ephemeris for target 16921-01-39P ephemeris data for target 16921-01-39P does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 21.213 to 23.182. ephemeris interval: 22.181 to 24.183 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. /private/var/folders/yl/s40978h128v5q7fw8lz60dnr0000gn/T/OPVisit8827510786368339068.xml This should include two orbits to acquire images in the three filters. 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