11535( 11) - 27-Sep-2011 15:55:52 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11535 Version: 11 Check-in Time: 27-Sep-2011 15:55:52 STScI Edit Number: 7 Title COS-GTO: Deep Search for an Oxygen Atmosphere on Callisto ------------------------------------------------------------------------------------ Type Cycle GTO/COS 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. James C. Green University of Colorado at Boulder CoI: Dr. Cynthia Froning University of Colorado at Boulder N CoI: Dr. John R. Spencer Southwest Research Institute Y ------------------------------------------------------------------------------------ Abstract We plan a deep search for 1304? and 1356? O emission from Callisto, to detect or place strong limits on the presence of a hypothesized O2 atmosphere on this moon (Liang et al. 2005). Tenuous oxygen atmospheres on Europa and Ganymede have been detected by HST using these emission lines, but searches for O emission from Callisto have not been successful (Strobel et al. 2002). The Liang et al. models predict O emission at levels comparable to the Strobel et al. upper limit, so the improved sensitivity of COS may be able to detect the emission, and thus Callisto's O2 atmosphere, for the first time. ------------------------------------------------------------------------------------ Observations Description ------------------------ Four orbits with the G130M grating at 1300?, to achieve >= 8000s. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 11535( 11) - 27-Sep-2011 15:55:52 - [ 2] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 TARGET NAME: CALLISTO ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE CALLISTO ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=JUPITER STD=CALLISTO ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS CML OF JUPITER FROM CALLISTO BETWEEN 42 148, SEP OF CALLISTO SUN FROM EARTH GT 150D ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 6.1 +/- 1 We want to observe Callisto during each visit when it is F(1356) = 15 R impacted by Jupiter's tilted & warped current sheet. The Jupiter system III longitudes where Callisto crosses the Ephemeris Center: EARTH current sheet are 296 and 116 degrees; we (arbitrarily) choose to observe the crossing centered on 116 degrees. The sheet should cross Callisto during the 1st half of the 2nd orbit; this allows ~25 minutes of flexibility. Additionally, as the oxygen lines to be observed are also present in terrestrial airglow, we choose to observe near opposition to maximize time in Earth's shadow. We specify this by requiring that the solar elongation of Callisto be greater than 150 degrees (we would prefer >160 degrees, but the period with >160 degree elongation is excluded from the observing window for some reason). ------------------------------------------------------------------------------------------------------------------------------------ 11535( 11) - 27-Sep-2011 15:55:52 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 TARGET NAME: CALLISTO-COPY ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE CALLISTO ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=JUPITER STD=CALLISTO ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS CML OF JUPITER FROM CALLISTO BETWEEN 42 148, SEP OF CALLISTO SUN FROM EARTH GT 150D ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 6.1 +/- 1 We want to observe Callisto during each visit when it is F(1356) = 15 R impacted by Jupiter's tilted & warped current sheet. The Jupiter system III longitudes where Callisto crosses the Ephemeris Center: EARTH current sheet are 296 and 116 degrees; we (arbitrarily) choose to observe the crossing centered on 116 degrees. The sheet should cross Callisto during the 1st half of the 2nd orbit; this allows ~25 minutes of flexibility. Additionally, as the oxygen lines to be observed are also present in terrestrial airglow, we choose to observe near opposition to maximize time in Earth's shadow. We specify this by requiring that the solar elongation of Callisto be greater than 150 degrees (we would prefer >160 degrees, but the period with >160 degree elongation is excluded from the observing window for some reason). ------------------------------------------------------------------------------------------------------------------------------------ 11535( 11) - 27-Sep-2011 15:55:52 - [ 4] Visit: 02 Visit Requirements: 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 CALLISTO COS/NUV ACQ/SEA PSA G285M 2709 SCAN-SIZE=3 1 5 S GS ACQ SCENARIO BASE1B3 RCH Comments: Callisto is 6.2 +/- 0.5 mags over 2009 (based on JPL ephem generator), and is effectively 1.1 mag dimmer in this grating bandpass than in the visible (based on albedo = 0.06 here vs. 0.17 in visible). So I use mV_effective = 7.3 and get 0.44/0.96 seconds for ACQ-Search/ACQ-PeakXD modes to reach S/N = 40 (ETC IDs COS78131 / COS78132). 5 seconds gives plenty of margin ------------------------------------------------------------------------------------------------------------------------------------ 2 CALLISTO COS/NUV ACQ/PEA PSA G285M 2709 1 5 S KXD Comments: Callisto is 6.2 +/- 0.5 mags over 2009 (based on JPL ephem generator), and is effectively 1.1 mag dimmer in this grating bandpass than in the visible (based on albedo = 0.06 here vs. 0.17 in visible). So I use mV_effective = 7.3 and get 0.44/0.96 seconds for ACQ-Search/ACQ-PeakXD modes to reach S/N = 40 (ETC IDs COS78131 / COS78132) ------------------------------------------------------------------------------------------------------------------------------------ 3 CALLISTO COS/NUV ACQ/PEA PSA G285M 2709 NUM-POS=7, STEP-SIZE=1.2 1 5 S KD Comments: estimates are same as for exposure 1, ACQ/SEARCH ------------------------------------------------------------------------------------------------------------------------------------ 4 CALLISTO COS/FUV TIME-TA PSA G130M 1291 FP-POS=1, BUFFER-TIME=685 1 795 S G Comments: COS76584 for calculation of buffer time. Assumes effective mV = 6.8 and 15 Rayleigh (8.2e-16 ergs/cm^2/s) 1356? line. Gives buffer time = 2/3 * 5939s. ------------------------------------------------------------------------------------------------------------------------------------ 5 CALLISTO COS/FUV TIME-TA PSA G130M 1291 FP-POS=2, BUFFER-TIME=660 1 660 S G ------------------------------------------------------------------------------------------------------------------------------------ 6 CALLISTO COS/FUV TIME-TA PSA G130M 1291 FP-POS=3, BUFFER-TIME=1311 1 1421 S G 11535( 11) - 27-Sep-2011 15:55:52 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------------------------------------------ 7 CALLISTO COS/FUV TIME-TA PSA G130M 1291 FP-POS=4, BUFFER-TIME=1290 1 1290 S G ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ CALLISTO 1 COS/NUV ACQ/SEA PSA G285M 2709 none none none none 1 N/A RCH CALLISTO 2 COS/NUV ACQ/PEA PSA G285M 2709 none none none none 1 N/A KXD CALLISTO 3 COS/NUV ACQ/PEA PSA G285M 2709 none none none none 1 N/A KD CALLISTO 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G CALLISTO 5 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G CALLISTO 6 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G CALLISTO 7 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G 11535( 11) - 27-Sep-2011 15:55:52 - [ 6] Visit: 03 Visit Requirements: 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 CALLISTO COS/NUV ACQ/SEA PSA G285M 2709 SCAN-SIZE=3 1 5 S GS ACQ SCENARIO BASE1B3 RCH Comments: Callisto is 6.2 +/- 0.5 mags over 2009 (based on JPL ephem generator), and is effectively 1.1 mag dimmer in this grating bandpass than in the visible (based on albedo = 0.06 here vs. 0.17 in visible). So I use mV_effective = 7.3 and get 0.44/0.96 seconds for ACQ-Search/ACQ-PeakXD modes to reach S/N = 40 (ETC IDs COS78131 / COS78132) ------------------------------------------------------------------------------------------------------------------------------------ 2 CALLISTO COS/NUV ACQ/PEA PSA G285M 2709 1 5 S KXD Comments: Callisto is 6.2 +/- 0.5 mags over 2009 (based on JPL ephem generator), and is effectively 1.1 mag dimmer in this grating bandpass than in the visible (based on albedo = 0.06 here vs. 0.17 in visible). So I use mV_effective = 7.3 and get 0.44/0.96 seconds for ACQ-Search/ACQ-PeakXD modes to reach S/N = 40 (ETC IDs COS78131 / COS78132) ------------------------------------------------------------------------------------------------------------------------------------ 3 CALLISTO COS/NUV ACQ/PEA PSA G285M 2709 NUM-POS=7, STEP-SIZE=1.2 1 5 S KD Comments: estimates are same as for exposure 1, ACQ/SEARCH ------------------------------------------------------------------------------------------------------------------------------------ 4 CALLISTO COS/FUV TIME-TA PSA G130M 1291 FP-POS=1, BUFFER-TIME=685 1 795 S G ------------------------------------------------------------------------------------------------------------------------------------ 5 CALLISTO COS/FUV TIME-TA PSA G130M 1291 FP-POS=2, BUFFER-TIME=660 1 660 S G ------------------------------------------------------------------------------------------------------------------------------------ 6 CALLISTO COS/FUV TIME-TA PSA G130M 1291 FP-POS=3, BUFFER-TIME=1311 1 1421 S G ------------------------------------------------------------------------------------------------------------------------------------ 7 CALLISTO COS/FUV TIME-TA PSA G130M 1291 FP-POS=4, BUFFER-TIME=1290 1 1290 S G ------------------------------------------------------------------------------------------------------------------------------------ 11535( 11) - 27-Sep-2011 15:55:52 - [ 7] 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 | ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ CALLISTO 1 COS/NUV ACQ/SEA PSA G285M 2709 none none none none 1 N/A RCH CALLISTO 2 COS/NUV ACQ/PEA PSA G285M 2709 none none none none 1 N/A KXD CALLISTO 3 COS/NUV ACQ/PEA PSA G285M 2709 none none none none 1 N/A KD CALLISTO 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G CALLISTO 5 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G CALLISTO 6 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G CALLISTO 7 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G 11535( 11) - 27-Sep-2011 15:55:52 - [ 8] Visit: 04 Visit Requirements: 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 CALLISTO-CO COS/NUV ACQ/SEA PSA G285M 2709 SCAN-SIZE=3 1 5 S GS ACQ SCENARIO BASE1B3 PY RCH Comments: Callisto is 6.2 +/- 0.5 mags over 2009 (based on JPL ephem generator), and is effectively 1.1 mag dimmer in this grating bandpass than in the visible (based on albedo = 0.06 here vs. 0.17 in visible). So I use mV_effective = 7.3 and get 0.44/0.96 seconds for ACQ-Search/ACQ-PeakXD modes to reach S/N = 40 (ETC IDs COS78131 / COS78132). 5 seconds gives plenty of margin ------------------------------------------------------------------------------------------------------------------------------------ 2 CALLISTO-CO COS/NUV ACQ/PEA PSA G285M 2709 1 5 S PY KXD Comments: Callisto is 6.2 +/- 0.5 mags over 2009 (based on JPL ephem generator), and is effectively 1.1 mag dimmer in this grating bandpass than in the visible (based on albedo = 0.06 here vs. 0.17 in visible). So I use mV_effective = 7.3 and get 0.44/0.96 seconds for ACQ-Search/ACQ-PeakXD modes to reach S/N = 40 (ETC IDs COS78131 / COS78132) ------------------------------------------------------------------------------------------------------------------------------------ 3 CALLISTO-CO COS/NUV ACQ/PEA PSA G285M 2709 NUM-POS=7, STEP-SIZE=1.2 1 5 S PY KD Comments: estimates are same as for exposure 1, ACQ/SEARCH ------------------------------------------------------------------------------------------------------------------------------------ 11535( 11) - 27-Sep-2011 15:55:52 - [ 9] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 4 CALLISTO-CO COS/FUV TIME-TA PSA G130M 1291 FP-POS=1, BUFFER-TIME=1712 1 1712 S POS TARG null, 0.9 PY G Comments: COS76584 for calculation of buffer time. Assumes effective mV = 6.8 and 15 Rayleigh (8.2e-16 ergs/cm^2/s) 1356? line. Gives buffer time = 2/3 * 5939s. POS TARG is designed to place Callisto 0.9" in the cross-dispersion (+Y) direction. This is intended to allow a portion of the the aperture, and therefore a portion of the spectrum, to contain purely airglow, while the upper part of the aperture contains Callisto's spectrum in addition to oxygen airglow. The cross-dispersion variation in oxygen emission line intensity will help indicate whether Callisto has a significant additional oxygen signal. ------------------------------------------------------------------------------------------------------------------------------------ 5 CALLISTO-CO COS/FUV TIME-TA PSA G130M 1291 FP-POS=2, BUFFER-TIME=1298 1 1408 S SAME POS AS 4 PY G ------------------------------------------------------------------------------------------------------------------------------------ 6 CALLISTO-CO COS/FUV TIME-TA PSA G130M 1291 FP-POS=4, BUFFER-TIME=1408 1 1408 S SAME POS AS 4 PY G ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ CALLISTO-COPY 1 COS/NUV ACQ/SEA PSA G285M 2709 none none none none 1 N/A RCH CALLISTO-COPY 2 COS/NUV ACQ/PEA PSA G285M 2709 none none none none 1 N/A KXD CALLISTO-COPY 3 COS/NUV ACQ/PEA PSA G285M 2709 none none none none 1 N/A KD CALLISTO-COPY 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 N/A G CALLISTO-COPY 5 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G CALLISTO-COPY 6 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 N/A G 11535( 11) - 27-Sep-2011 15:55:52 - [ 10] Summary Form for Proposal 11535 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAKD, ACQ/PEAKXD, ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1290, BUFFER-TIME=1298, BUFFER-TIME=1311, BUFFER-TIME=1408, BUFFER-TIME=1712, BUFFER-TIME=660, BUFFER-TIME=685, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, NUM-POS=7, SCAN-SIZE=3, STEP-SIZE=1.2 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO BASE1B3, POS TARG null, 0.9, SAME POS AS 4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, G285M ------------------------------------------------------------------------------------------------------------------------------------ Target Names CALLISTO, CALLISTO-COPY ------------------------------------------------------------------------------------------------------------------------------------