14609( 7) - 17-Mar-2017 17:43:19 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14609 Version: 7 Check-in Time: 17-Mar-2017 17:43:19 STScI Edit Number: 4 Title Psyche's UV Reflectance Spectra: Exploring the origins of the largest exposed-core metallic asteroid ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Tracy M Becker Southwest Research Institute Y CoI: Dr. Kurt David Retherford Southwest Research Institute N CoI: Dr. Lorenz Roth Royal Institute of Technology N CoI: Dr. Nathaniel J. Cunningham Nebraska Wesleyan University N CoI: Dr. Lori M. Feaga University of Maryland N CoI: Dr. Linda Elkins-Tanton Arizona State University N CoI: Dr. Jan-Erik Wahlund The Swedish Institute of Space Physics N (IRF) ------------------------------------------------------------------------------------ Abstract (16) Psyche is the largest of the M-class asteroids, and is presumed to be the exposed core of a differentiated asteroid stripped of its mantle through hit-and-run collisions. However, other origins for Psyche have been proposed, including that it formed from a highly-reduced, metal rich material in the inner solar system or that its surface is olivine that has been space weathered. If (16) Psyche is an exposed core, then studying its properties enhances our understanding of the cores of all terrestrial planets, including the Earth's. If it accreted in the inner part of the solar system and was later injected into the asteroid belt, then Psyche sheds light on the conditions and subsequent evolution of the early solar system. Lastly, if Psyche is weathered olivine, then olivine may be more abundant in the solar system than currently measured, rectifying the so-called "Great Dunite Shortage". Our program to obtain high-resolution UV spectra of Psyche with the COS G140L mode and the STIS NUV MAMA G230L mode to measure spectral signatures between 90 - 315 nm is designed to distinguish between the 3 hypothesized cases. These observations will enable identification of absorption bands, especially Fe-O charge transfer bands and will be sensitive to "spectral blueing" that occurs at UV wavelengths for space-weathered objects. When combined, the presence of these UV features, or not, provides a novel test of Psyche formation theories. ------------------------------------------------------------------------------------ Observations Description ------------------------ We plan to observe (16) Psyche with two visits composed of two orbits each, with each pair of orbits dedicated to FUV and NUV spectral albedo measurements, respectively. The COS G140L mode centered at 128 nm will be used to obtain high-resolution spectra at wavelengths between ~90 - 205 nm, and would produce the first FUV spectrum of Psyche. The STIS 1st order NUV MAMA G230L mode with 52 x 0.2 slit will be used to obtain NUV spectra for the wavelength range 165 - 310 nm. We will alternate one bandpass per orbit, in two orbits per visit (FUV then NUV). During each visit, we will acquire two 1200-sec COS G140L exposures and two 1400-sec STIS NUV MAMA G230L exposures. We plan to schedule the visits so that the hemisphere viewed with each bandpass (mode) is separated by as 14609( 7) - 17-Mar-2017 17:43:19 - [ 2] close to 180 degrees as possible, for an asteroid with a 4.196-hour rotation period. Psyche's position will be offset in the 2.5-arcsec aperture by 0.5 arcsec in the COS observations in order to distinguish between signal from Psyche versus extended emissions from the geocorona + sky background. Psyche is offset toward the bottom of the aperture to avoid gain-sagged regions located higher on the detector. The empty pixels in the COS field of view in the detector rows adjacent to the Psyche spectrum for each observation are used to simultaneously measure the geocorona and sky background features. TIME-TAG mode will be used for both COS and STIS MAMA datasets. An essential requirement is to capture (16) Psyche within 4 weeks of opposition (March 3, 2017) to maximize both the size of the asteroid and also the amount of time in Earth's shadow, reducing the FUV Lyman-alpha background from terrestrial airglow from ~10-15 kR to ~2.5-4 kR. ------------------------------------------------------------------------------------ 14609( 7) - 17-Mar-2017 17:43:19 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 TARGET NAME: PSYCHE ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: ASTEROID Large, M-type asteroid in the asteroid belt ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 TYPE=ASTEROID, A=2.920561880671045, E=.1382408738943603, I=3.093366819603944, O=150.4660463936781, W=229.1191158619876, M=335.4933059174967, EQUINOX=J2000, EPOCH=01-JAN-2000:00:00:00, EpochTimeScale=TDB ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 10.26 Ephemeris Center: EARTH Extended: YES ------------------------------------------------------------------------------------------------------------------------------------ 14609( 7) - 17-Mar-2017 17:43:19 - [ 4] Visit: 01 (Visit 1 - COS) Visit Requirements: BETWEEN 03-FEB-2017:00:00:00 AND 31-MAR-2017:00:00:00 On Hold Comments: Additional Comments: 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 PSYCHE COS/FUV ACQ/SEA PSA G140L 1280 SCAN-SIZE=3 1 6 S (6 S) RCH ------------------------------------------------------------------------------------------------------------------------------------ 2 PSYCHE COS/FUV TIME-TA PSA G140L 1280 BUFFER-TIME=14900, FP-POS=ALL 1 60 S POS TARG null, -00.50 G see below (1816 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 | ------------------------------------------------------------------------------------------------------------------------------------ PSYCHE 1 COS/FUV ACQ/SEA PSA G140L 1280 none none none none 1 N/A RCH PSYCHE 2 COS/FUV TIME-TA PSA G140L 1280 none none none 1 1 454.0 S G PSYCHE 2 COS/FUV TIME-TA PSA G140L 1280 none none none 2 1 454.0 S G PSYCHE 2 COS/FUV TIME-TA PSA G140L 1280 none none none 3 1 454.0 S G PSYCHE 2 COS/FUV TIME-TA PSA G140L 1280 none none none 4 1 454.0 S G 14609( 7) - 17-Mar-2017 17:43:19 - [ 5] Visit: 02 (Visit 2 - STIS) Visit Requirements: BETWEEN 03-FEB-2017:00:00:00 AND 07-APR-2017:00:00:00 On Hold Comments: Additional Comments: The timing of the visit is meant to view the hemisphere of Psyche nearly 180 degrees from the Visit 1 observations. Psyche's orbit is ~4.1 hours. 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 PSYCHE STIS/CCD ACQ F28X50LP MIRROR 1 .5 S (0.5 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PSYCHE STIS/NUV TIME-TA 52X0.2 G230L 2376 BUFFER-TIME=340 1 1000 S -MAMA G see below (2288 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 | ------------------------------------------------------------------------------------------------------------------------------------ PSYCHE 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A PSYCHE 2 STIS/NUV TIME-TA 52X0.2 G230L 2376 none none none none 1 2288.0 S -MAMA G 14609( 7) - 17-Mar-2017 17:43:19 - [ 6] Visit: 03 (Visit 3 - COS) Visit Requirements: BETWEEN 03-FEB-2017:00:00:00 AND 31-MAR-2017:00:00:00 On Hold Comments: Additional Comments: The timing of the visit is meant to view the hemisphere of Psyche nearly 180 degrees from the Visit 1 observations. Psyche's orbit is ~4.1 hours. 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 PSYCHE COS/FUV ACQ/SEA PSA G140L 1280 SCAN-SIZE=3 1 6 S (6 S) RCH ------------------------------------------------------------------------------------------------------------------------------------ 2 PSYCHE COS/FUV TIME-TA PSA G140L 1280 BUFFER-TIME=14900, FP-POS=ALL 1 60 S POS TARG null, -00.50 G see below (1816 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 | ------------------------------------------------------------------------------------------------------------------------------------ PSYCHE 1 COS/FUV ACQ/SEA PSA G140L 1280 none none none none 1 N/A RCH PSYCHE 2 COS/FUV TIME-TA PSA G140L 1280 none none none 1 1 454.0 S G PSYCHE 2 COS/FUV TIME-TA PSA G140L 1280 none none none 2 1 454.0 S G PSYCHE 2 COS/FUV TIME-TA PSA G140L 1280 none none none 3 1 454.0 S G PSYCHE 2 COS/FUV TIME-TA PSA G140L 1280 none none none 4 1 454.0 S G 14609( 7) - 17-Mar-2017 17:43:19 - [ 7] Visit: 04 (Visit 4 - STIS) Visit Requirements: BETWEEN 03-FEB-2017:00:00:00 AND 31-MAR-2017:00:00:00 On Hold Comments: Additional Comments: The timing of the visit is meant to view the same hemisphere of Psyche as the Visit 1 observations. Psyche's orbit is ~4.1 hours. 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 PSYCHE STIS/CCD ACQ F28X50LP MIRROR 1 .5 S (0.5 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PSYCHE STIS/NUV TIME-TA 52X0.2 G230L 2376 BUFFER-TIME=340 1 1000 S -MAMA G see below (2288 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 | ------------------------------------------------------------------------------------------------------------------------------------ PSYCHE 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A PSYCHE 2 STIS/NUV TIME-TA 52X0.2 G230L 2376 none none none none 1 2288.0 S -MAMA G 14609( 7) - 17-Mar-2017 17:43:19 - [ 8] Visit: 54 (Visit 54 - STIS) Visit Requirements: BETWEEN 03-FEB-2017:00:00:00 AND 07-APR-2017:00:00:00 On Hold Comments: Additional Comments: The timing of the visit is meant to view the same hemisphere of Psyche as the Visit 1 observations. Psyche's orbit is ~4.1 hours. 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 PSYCHE STIS/CCD ACQ F28X50LP MIRROR 1 .5 S (0.5 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PSYCHE STIS/NUV TIME-TA 52X0.2 G230L 2376 BUFFER-TIME=340 1 1000 S -MAMA G see below (2288 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 | ------------------------------------------------------------------------------------------------------------------------------------ PSYCHE 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A PSYCHE 2 STIS/NUV TIME-TA 52X0.2 G230L 2376 none none none none 1 2288.0 S -MAMA G 14609( 7) - 17-Mar-2017 17:43:19 - [ 9] Summary Form for Proposal 14609 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2, F28X50LP, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, STIS/CCD, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ, ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=14900, BUFFER-TIME=340, FP-POS=ALL, SCAN-SIZE=3 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 03-FEB-2017:00:00:00 AND 07-APR-2017:00:00:00, BETWEEN 03-FEB-2017:00:00:00 AND 31-MAR-2017:00:00:00, POS TARG null, -00.50 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, G230L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names PSYCHE ------------------------------------------------------------------------------------------------------------------------------------