16921( 6) - 11-Jul-2022 12:09:46 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16921 Version: 6 Check-in Time: 11-Jul-2022 12:09:46 STScI Edit Number: 1 Title Enabling a First in a Lifetime Multi-Wavelength Gas and Dust Coma Characterization of the Centaur 39P/Oterma ------------------------------------------------------------------------------------ Type Cycle GO 29 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Charles Schambeau University of Central Florida Board of Y Trustees CoI: Dr. Adam McKay American University N CoI: Dr. Eva Lilly Planetary Science Institute N CoI: Dr. Yanga Fernandez University of Central Florida Board of N Trustees CoI: Olga Harrington Pinto University of Central Florida Board of N Trustees CoI: Dr. Theodore Richard Kareta Lowell Observatory N ------------------------------------------------------------------------------------ Abstract 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. ------------------------------------------------------------------------------------ Observations Description ------------------------ 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 16921( 6) - 11-Jul-2022 12:09:46 - [ 2] 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. ------------------------------------------------------------------------------------ 16921( 6) - 11-Jul-2022 12:09:46 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 TARGET NAME: 39P ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: COMET Comet and Active Centaur 39P/Oterma ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 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 ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 24 Ephemeris Center: EARTH Acquisition Uncertainty: 1.0 " Extended: YES ------------------------------------------------------------------------------------------------------------------------------------ 16921( 6) - 11-Jul-2022 12:09:46 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE-3PT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.135 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.135 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 16921( 6) - 11-Jul-2022 12:09:46 - [ 5] Visit: 01 (39P images) Visit Requirements: BETWEEN 08-JUL-2022:00:00:00 AND 28-JUL-2022:00:00:00; BETWEEN 29-JUL-2022:00:00:00 AND 22-AUG-2022:00:00:00 On Hold Comments: Additional Comments: This should include two orbits to acquire images in the three filters. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 39P WFC3/UVI ACCUM UVIS2-C1K F475W FLASH=12 1 400 S PATTERN 1 1 S 1C-SUB see below (1128 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 39P WFC3/UVI ACCUM UVIS2-C1K F625W FLASH=12 1 300 S PATTERN 2 2 S 1C-SUB see below (590 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 39P WFC3/UVI ACCUM UVIS2-C1K F625W FLASH=12 1 300 S POS TARG 0.135, 0.135 S 1C-SUB see below (358 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 39P WFC3/UVI ACCUM UVIS2-C1K F775W FLASH=12 1 450 S PATTERN 1 4 S 1C-SUB see below (1524 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ 39P 1 WFC3/UVI ACCUM UVIS2-C1 F475W 1 none none none 1 376.0 S S K1C-SUB 39P 1 WFC3/UVI ACCUM UVIS2-C1 F475W 2 none none none 1 376.0 S S K1C-SUB 39P 1 WFC3/UVI ACCUM UVIS2-C1 F475W 3 none none none 1 376.0 S S K1C-SUB 39P 2 WFC3/UVI ACCUM UVIS2-C1 F625W 1 none none none 1 295.0 S S K1C-SUB 39P 2 WFC3/UVI ACCUM UVIS2-C1 F625W 2 none none none 1 295.0 S S K1C-SUB 39P 3 WFC3/UVI ACCUM UVIS2-C1 F625W none none none none 2 358.0 S S K1C-SUB 39P 4 WFC3/UVI ACCUM UVIS2-C1 F775W 1 none none none 2 508.0 S S K1C-SUB 39P 4 WFC3/UVI ACCUM UVIS2-C1 F775W 2 none none none 2 508.0 S S K1C-SUB 39P 4 WFC3/UVI ACCUM UVIS2-C1 F775W 3 none none none 2 508.0 S S K1C-SUB 16921( 6) - 11-Jul-2022 12:09:46 - [ 6] Summary Form for Proposal 16921 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2-C1K1C-SUB ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=12 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 08-JUL-2022:00:00:00 AND 28-JUL-2022:00:00:00, BETWEEN 29-JUL-2022:00:00:00 AND 22-AUG-2022:00:00:00, PATTERN 1 1, PATTERN 1 4, PATTERN 2 2, POS TARG 0.135, 0.135 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F475W, F625W, F775W ------------------------------------------------------------------------------------------------------------------------------------ Target Names 39P ------------------------------------------------------------------------------------------------------------------------------------