0Assigned ID: 1007
----- Attempting Submission 1 (Mon Feb 11 13:06:56 GMT 2013) -----Post HOPR Submission751752003----- Attempting Submission 1 (Thu Jun 27 11:20:44 GMT 2013) -----
----- Attempting Submission 2 (Thu Jan 30 13:25:56 GMT 2014) -----FP-POS settings changed to keep 1304 OI line in the detectorObserving Ganymede's atmosphere and auroras with COS and STISJupiter's satellite Ganymede is one of the solar system's most intriguing moons, and the importance of studying Ganymede is vividly highlighted by the recent selection of the ESA L-class mission JUICE. Ganymede possesses an oxygen atmosphere and the only known 'magnetosphere within a magnetosphere', and the continuous impingement of Jupiter's magnetospheric plasma on Ganymede thus makes the satellite an ideal control case for studying the interaction of any cosmic body with an external wind. Auroral emissions are crucial diagnostics of this interaction, but spectra of Ganymede's FUV auroras have only been obtained with GHRS and STIS. Fundamental outstanding questions thus remain as to the nature of this unique satellites's atmosphere and its magnetosphere, and we will use the significantly improved sensitivity of COS, combined with the imaging capabilities of STIS, to examine Ganymede's FUV atmospheric emissions in order to answer the following questions:
* How does Ganymede's magnetosphere interact with Jupiter's?
* What is the nature of Ganymede's oxygen atmosphere?
Ganymede has never been observed with COS, and STIS observations of both hemispheres have not been obtained in the same epoch, such that this program will provide the most significant advancements in our understanding of the atmosphere and magnetosphere of this enigmatic satellite for over a decade. HST is the only observatory capable of obtaining these observations and execution of this program during Cycle 21 is extremely highly desirable, since the unprecedented new information these observations will return are urgently required by those who are now designing instruments for the JUICE mission.The proposed observations will consist of COS and STIS exposures of Ganymede near eastern and western elongation, with two visits scheduled 1/2 Ganymede orbit apart. Each visit will consist of 4 orbits, 2 COS and 2 STIS, for a total of 8 orbits in the program. In orbits 1, 2, and 4 in each visit, Ganymede will first be acquired. The first and last orbit in each visit will consist of STIS/FUV-MAMA G140L 52X2 TIME-TAG spectroscopy, while the middle two orbits will consist of COS/FUV G140L TIME-TAG spectroscopy of the reflected solar continuum from the surface of Ganymede, plus the atmospheric absorption and airglow/auroral emissions. Ideally, the STIS and COS orbits would be contiguous, such that the first and last STIS image in each visit will be obtained roughly half a jovian rotation apart in order to capture variability.SOLAR SYSTEM12falsetrue0.00.0falsefalsefalseSUPPORTEDSOLAR SYSTEMGanymede within +/-20 degrees of eastern elongation and within +/- 30 degrees of opposition. These constraints could be relaxed somewhat to ease scheduling if necessary.SATELLITESATELLITE GANYMEDESTD=JUPITERSTD=GANYMEDESEP OF GANYMEDE-EAST JUPITER FROM EARTH GT 30",
SEP OF GANYMEDE-EAST CALLISTO FROM EARTH GT 10",
SEP OF GANYMEDE-EAST IO FROM EARTH GT 10",
SEP OF GANYMEDE-EAST EUROPA FROM EARTH GT 10",
OLG OF GANYMEDE-EAST BETWEEN 70 110,
SEP OF GANYMEDE-EAST SUN FROM EARTH GT 150DEARTHSOLAR SYSTEMGanymede within +/-20 degrees of western elongation and within +/- 30 degrees of opposition. These constraints could be relaxed somewhat to ease scheduling if necessary.SATELLITESATELLITE GANYMEDESTD=JUPITERSTD=GANYMEDESEP OF GANYMEDE-WEST JUPITER FROM EARTH GT 30",
SEP OF GANYMEDE-WEST CALLISTO FROM EARTH GT 10",
SEP OF GANYMEDE-WEST IO FROM EARTH GT 10",
SEP OF GANYMEDE-WEST EUROPA FROM EARTH GT 10",
OLG OF GANYMEDE-WEST BETWEEN 250 290,
SEP OF GANYMEDE-WEST SUN FROM EARTH GT 150DEARTHSOLAR SYSTEMGanymede within +/-20 degrees of western elongation and within +/- 30 degrees of opposition. These constraints could be relaxed somewhat to ease scheduling if necessary.SATELLITESATELLITE GANYMEDESTD=JUPITERSTD=GANYMEDESEP OF GANYMEDE-WEST-EXTENDED JUPITER FROM EARTH GT 30",
SEP OF GANYMEDE-WEST-EXTENDED CALLISTO FROM EARTH GT 10",
SEP OF GANYMEDE-WEST-EXTENDED IO FROM EARTH GT 10",
SEP OF GANYMEDE-WEST-EXTENDED EUROPA FROM EARTH GT 10",
OLG OF GANYMEDE-WEST-EXTENDED BETWEEN 250 290,
SEP OF GANYMEDE-WEST-EXTENDED SUN FROM EARTH GT 120DEARTHSTIS/FUV-MAMASpectroscopicNoNoG140L1425COS/FUVSpectroscopicNoNoG140L1280STIS/FUV-MAMASpectroscopicNoNoG140L1425STIS/FUV-MAMASpectroscopicNoNoG140L1425COS/FUVSpectroscopicNoNoG140L1280STIS/FUV-MAMASpectroscopicNoNoG140L1425Using ephemeris for target 13328-G1-GANYMEDE-EASTephemeris data for target 13328-G1-GANYMEDE-EAST does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 13.357 to 15.092. ephemeris interval: 13.365 to 16.001Timing link suitability includes constraints ([G2 After G1 by 2.5 to 4.5 days] [G3 After G1 by 2.5 to 4.5 days])The scheduling data was generated by CASM 21.2.CASM was run in Phase II mode.Eastern elongation - defined by target.139049555200099.0324950499737(Tic-Visit
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)true40Ganymede V mag near to opposition is ~4.6. Surface brightness for disc of diameter 1.7" is then ~5.5. In ETC run STIS.ta.510225, I used a Castelli-Kurucz G2V spectrum normalised to V = 5.5 / arcsec squared and diameter = 1.7. The minimum exposure time is less than the CCD saturation time of ~0.5 s.In STIS.sp.517958 I used an archive spectrum of the same target and instrument set-up. Buffer Time = Texp / 2.
POS-TARG of y=-4" moves the target out of the blotch region (slightly less than does the 52X2D1 aperture, but the target is >1")In STIS.sp.517958 I used an archive spectrum of the same target and instrument set-up. Buffer Time = Texp / 2.
POS-TARG of y=-4" moves the target out of the blotch region (slightly less than does the 52X2D1 aperture, but the target is >1")Ganymede V mag near to opposition is ~4.6, and the surface brightness for a disc of diameter 1.7" is then ~5.5. Ganymede's albedo over 2400-3000 A ranges from ~7% on the trailing side to ~20% on the leading side (Nelson et al., 1987), vs. ~43% in the visible, and is thus ~0.8-2.0 mags dimmer in this waveband than in the visible. ACQ/SEARCH ETC runs using an extended source (a normalised Castelli-Kurucz G2V spectrum), yield for the BOA/MIRRORA:
mV_eff = 7.5 (COS.ta.517264) Texp(SNR = 60) = 2.4873 s
mV_eff = 6.3 (COS.ta.517265 ) Texp(SNR = 60) = 0.7901 s
Using a 3 s exposure then gives a good SNR for all cases:
mV_eff = 7.5 (COS.ta.517267) SNR(Texp = 3 s) = 65.8941, total count rate = 2,554.089 counts/s
mV_eff = 6.3 (COS.ta.517268 ) SNR(Texp = 3 s) = 116.915, total count rate = 5,667.150 counts/sThis exposure is to verify Ganymede's position in the aperture. We have the same Texp and count rates as for Exposure 5, but imaging ETC runs give SNRs of:
mV_eff = 7.5 (COS.im.517270) SNR(Texp = 3 s) = 46.1111, total count rate = 2,554.089 counts/s
mV_eff = 6.3 (COS.im.517273) SNR(Texp = 3 s) = 80.2784, total count rate = 5,667.150 counts/sGanymede V mag near to opposition is ~4.6, and the surface brightness for a disc of diameter 1.7" is then ~5.5. Ganymede's albedo in near 1400 A is ~2.3% (Feldman et al., 2000), vs. ~43% in the visible, and is thus ~3.2 mags dimmer in this waveband than in the visible. In ETC run COS.sp.517981 I used a Castelli-Kurucz G2V spectrum normalised to mV_eff = 8.7 / arcsec squared and diameter = 1.7", plus two emission lines representative of the fluxes observed by Feldman et al. (2000):
Center 1304.0 A FWHM 30.0 A Flux 2.3e-15 erg/cm^2/s
Center 1356.0 A FWHM 30.0 A Flux 4.4e-15 erg/cm^2/s
The Buffer Time is 19,639 s, thus well over an orbit. Here, I've used Texp - 110 to minimise the time between the two exposures.ETC Buffer Time is, as for Exposure 6, ~20k s. Multiplied by 2/3 = 13092, rounded down to 13,000 s as this is the second exposure in the orbit.ETC Buffer Time is, as for Exposure 6, ~20k s. Here, I've used Texp - 110 to minimise the time between the two exposures.ETC Buffer Time is, as for Exposure 6, ~20k s. Multiplied by 2/3 = 13092, rounded down to 13,000 s as this is the second exposure in the orbit.Ganymede V mag near to opposition is ~4.6. Surface brightness for disc of diameter 1.7" is then 5.6. In ETC run STIS.ta.510225, I used a Castelli-Kurucz G2V spectrum normalised to V = 5.6 / arcsec squared and diameter = 1.7.In STIS.sp.517958 I used an archive spectrum of the same target and instrument set-up. Buffer Time = Texp / 2.
POS-TARG of y=-4" moves the target out of the blotch region (slightly less than does the 52X2D1 aperture, but the target is >1")In STIS.sp.517958 I used an archive spectrum of the same target and instrument set-up. Buffer Time = Texp / 2.
POS-TARG of y=-4" moves the target out of the blotch region (slightly less than does the 52X2D1 aperture, but the target is >1")Using ephemeris for target 13328-G2-GANYMEDE-WESTephemeris data for target 13328-G2-GANYMEDE-WEST does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 13.357 to 15.092. ephemeris interval: 13.365 to 16.001Timing link suitability includes constraints ([G2 After G1 by 2.5 to 4.5 days])The scheduling data was generated by CASM 21.2.CASM was run in Phase II mode.Western elongation - defined by target. The AFTER timing requirement ensures that the two visits occur in the same orbit of the satellite, a key aspect of this proposal. If scheduling is difficult, this could be interpreted as BEFORE by the same amount of time.139082268500095.85522957065149(Tic-Visit
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)true40Ganymede V mag near to opposition is ~4.6. Surface brightness for disc of diameter 1.7" is then ~5.5. In ETC run STIS.ta.510225, I used a Castelli-Kurucz G2V spectrum normalised to V = 5.5 / arcsec squared and diameter = 1.7. The minimum exposure time is less than the CCD saturation time of ~0.5 s.In STIS.sp.517958 I used an archive spectrum of the same target and instrument set-up. Buffer Time = Texp / 2.
POS-TARG of y=-4" moves the target out of the blotch region (slightly less than does the 52X2D1 aperture, but the target is >1")In STIS.sp.517958 I used an archive spectrum of the same target and instrument set-up. Buffer Time = Texp / 2.
POS-TARG of y=-4" moves the target out of the blotch region (slightly less than does the 52X2D1 aperture, but the target is >1")Ganymede V mag near to opposition is ~4.6, and the surface brightness for a disc of diameter 1.7" is then ~5.5. Ganymede's albedo over 2400-3000 A ranges from ~7% on the trailing side to ~20% on the leading side (Nelson et al., 1987), vs. ~43% in the visible, and is thus ~0.8-2.0 mags dimmer in this waveband than in the visible. ACQ/SEARCH ETC runs using an extended source (a normalised Castelli-Kurucz G2V spectrum), yield for the BOA/MIRRORA:
mV_eff = 7.5 (COS.ta.517264) Texp(SNR = 60) = 2.4873 s
mV_eff = 6.3 (COS.ta.517265 ) Texp(SNR = 60) = 0.7901 s
Using a 3 s exposure then gives a good SNR for all cases:
mV_eff = 7.5 (COS.ta.517267) SNR(Texp = 3 s) = 65.8941, total count rate = 2,554.089 counts/s
mV_eff = 6.3 (COS.ta.517268 ) SNR(Texp = 3 s) = 116.915, total count rate = 5,667.150 counts/sThis exposure is to verify Ganymede's position in the aperture. We have the same Texp and count rates as for Exposure 5, but imaging ETC runs give SNRs of:
mV_eff = 7.5 (COS.im.517270) SNR(Texp = 3 s) = 46.1111, total count rate = 2,554.089 counts/s
mV_eff = 6.3 (COS.im.517273) SNR(Texp = 3 s) = 80.2784, total count rate = 5,667.150 counts/sGanymede V mag near to opposition is ~4.6, and the surface brightness for a disc of diameter 1.7" is then ~5.5. Ganymede's albedo in near 1400 A is ~2.3% (Feldman et al., 2000), vs. ~43% in the visible, and is thus ~3.2 mags dimmer in this waveband than in the visible. In ETC run COS.sp.517981 I used a Castelli-Kurucz G2V spectrum normalised to mV_eff = 8.7 / arcsec squared and diameter = 1.7", plus two emission lines representative of the fluxes observed by Feldman et al. (2000):
Center 1304.0 A FWHM 30.0 A Flux 2.3e-15 erg/cm^2/s
Center 1356.0 A FWHM 30.0 A Flux 4.4e-15 erg/cm^2/s
The Buffer Time is 19,639 s, thus well over an orbit. Here, I've used Texp - 110 to minimise the time between the two exposures.ETC Buffer Time is, as for Exposure 6, ~20k s. Multiplied by 2/3 = 13092, rounded down to 13,000 s as this is the second exposure in the orbit.ETC Buffer Time is, as for Exposure 6, ~20k s. Here, I've used Texp - 110 to minimise the time between the two exposures.ETC Buffer Time is, as for Exposure 6, ~20k s. Multiplied by 2/3 = 13092, rounded down to 13,000 s as this is the second exposure in the orbit.Ganymede V mag near to opposition is ~4.6. Surface brightness for disc of diameter 1.7" is then 5.6. In ETC run STIS.ta.510225, I used a Castelli-Kurucz G2V spectrum normalised to V = 5.6 / arcsec squared and diameter = 1.7.In STIS.sp.517958 I used an archive spectrum of the same target and instrument set-up. Buffer Time = Texp / 2.
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POS-TARG of y=-4" moves the target out of the blotch region (slightly less than does the 52X2D1 aperture, but the target is >1")Using ephemeris for target 13328-G3-GANYMEDE-WEST-EXTENDEDephemeris data for target 13328-G3-GANYMEDE-WEST-EXTENDED does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 13.357 to 15.092. ephemeris interval: 13.365 to 16.001Timing link suitability includes constraints ([G3 After G1 by 2.5 to 4.5 days])The scheduling data was generated by CASM 21.2.CASM was run in Phase II mode.Western elongation - defined by target. The AFTER timing requirement ensures that the two visits occur in the same orbit of the satellite, a key aspect of this proposal. If scheduling is difficult, this could be interpreted as BEFORE by the same amount of time.(Tic-Visit
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)false30Ganymede V mag near to opposition is ~4.6, and the surface brightness for a disc of diameter 1.7" is then ~5.5. Ganymede's albedo over 2400-3000 A ranges from ~7% on the trailing side to ~20% on the leading side (Nelson et al., 1987), vs. ~43% in the visible, and is thus ~0.8-2.0 mags dimmer in this waveband than in the visible. ACQ/SEARCH ETC runs using an extended source (a normalised Castelli-Kurucz G2V spectrum), yield for the BOA/MIRRORA:
mV_eff = 7.5 (COS.ta.517264) Texp(SNR = 60) = 2.4873 s
mV_eff = 6.3 (COS.ta.517265 ) Texp(SNR = 60) = 0.7901 s
Using a 3 s exposure then gives a good SNR for all cases:
mV_eff = 7.5 (COS.ta.517267) SNR(Texp = 3 s) = 65.8941, total count rate = 2,554.089 counts/s
mV_eff = 6.3 (COS.ta.517268 ) SNR(Texp = 3 s) = 116.915, total count rate = 5,667.150 counts/sThis exposure is to verify Ganymede's position in the aperture. We have the same Texp and count rates as for Exposure 5, but imaging ETC runs give SNRs of:
mV_eff = 7.5 (COS.im.517270) SNR(Texp = 3 s) = 46.1111, total count rate = 2,554.089 counts/s
mV_eff = 6.3 (COS.im.517273) SNR(Texp = 3 s) = 80.2784, total count rate = 5,667.150 counts/sGanymede V mag near to opposition is ~4.6, and the surface brightness for a disc of diameter 1.7" is then ~5.5. Ganymede's albedo in near 1400 A is ~2.3% (Feldman et al., 2000), vs. ~43% in the visible, and is thus ~3.2 mags dimmer in this waveband than in the visible. In ETC run COS.sp.517981 I used a Castelli-Kurucz G2V spectrum normalised to mV_eff = 8.7 / arcsec squared and diameter = 1.7", plus two emission lines representative of the fluxes observed by Feldman et al. (2000):
Center 1304.0 A FWHM 30.0 A Flux 2.3e-15 erg/cm^2/s
Center 1356.0 A FWHM 30.0 A Flux 4.4e-15 erg/cm^2/s
The Buffer Time is 19,639 s, thus well over an orbit. Here, I've used Texp - 110 to minimise the time between the two exposures.ETC Buffer Time is, as for Exposure 6, ~20k s. Multiplied by 2/3 = 13092, rounded down to 13,000 s as this is the second exposure in the orbit.ETC Buffer Time is, as for Exposure 6, ~20k s. Here, I've used Texp - 110 to minimise the time between the two exposures.ETC Buffer Time is, as for Exposure 6, ~20k s. Multiplied by 2/3 = 13092, rounded down to 13,000 s as this is the second exposure in the orbit.Ganymede V mag near to opposition is ~4.6. Surface brightness for disc of diameter 1.7" is then 5.6. In ETC run STIS.ta.510225, I used a Castelli-Kurucz G2V spectrum normalised to V = 5.6 / arcsec squared and diameter = 1.7.In STIS.sp.517958 I used an archive spectrum of the same target and instrument set-up. Buffer Time = Texp / 2.
POS-TARG of y=-4" moves the target out of the blotch region (slightly less than does the 52X2D1 aperture, but the target is >1")In STIS.sp.517958 I used an archive spectrum of the same target and instrument set-up. Buffer Time = Texp / 2.
POS-TARG of y=-4" moves the target out of the blotch region (slightly less than does the 52X2D1 aperture, but the target is >1")