7241( 15) - 09/26/97 15:07 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7241 Version: 15 Check-in Date: 26-Sep-1997 15:06:24 1.Proposal Title: NEAR-IR SPECTRAL REFLECTANCE OF THE JUPITER RING ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle SOLAR SYSTEM GTO/NIC 7 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: BRADFORD A. SMITH INSTITUTE FOR ASTRONOMY CoI: ERIC BECKLIN UNIVERSITY OF CALIFORNIA AT LOS ANGELES N CoI: ROLAND MEIER UNIVERSITY OF HAWAII N CoI: RICHARD TERRILE JET PROPULSION LABORATORY N ------------------------------------------------------------------------------------ 6. Abstract The near-infrared spectral reflectance of the Jupiter dust ring is poorly known because of problems with scattered light from the planet. Suggested sources of ring material are dust particles sputtered off Amalthea or the nearby small satellites, Metis and Adrastea. Another possibility is material which has been volcanically ejected from Io. The filters selected are capable of detecting the presence of transient ice crystals, if such exist. The observations should be made between September 12, 1997 and October 31, 1997, as close as possible to the time that the Earth crosses Jupiter's ring plane. Observations should also be made in the absence of any nearby Galilean satellites, but with Metis and/or Adrastea within the field of view. Comparison of the ring's near-infrared spectral reflectance with that of Metis/Adrastea, Amalthea, and Io may help identify the source of the ring material. ------------------------------------------------------------------------------------ 7241( 15) - 09/26/97 15:07 - [ 2] Observations Description ------------------------ During a single orbit we intend to image one ansa of the Jovian ring, preferentially the sunward, i.e. western ansa. The main objective of this program is to do accurate photometry on the Jovian ring at three different colors. For this purpose we select wide-band filters F110W, F160W, and F205W. NICMOS camera 2 is the prime instrument used. Observations should be scheduled near the time when the Earth crosses the Jovian ring plane. The ring plane has to be observed nearly edge-on to achieve maximal column densities in the ring. The apparent, sky-projected width of the ring plane should not greatly exceed the approximate size of a detector pixel. For camera NIC2 this corresponds to an angular width of roughly 0.075 arcseconds. This geometrical constraint translates into a time window that extends from about September 12, 1997 to about October 31, 1997. Within this acceptable window we prefer to do the observations early, as both the surface brightness and the spatial scale of the ring gradually decrease with time. Also note that the optimal time is somewhat earlier than what the original abstract claimed. Jupiter as well as all four Galilean satellites must be outside the field of view. In turn, one or both ring satellites Metis and/or Adrastea should be in the field of view. At least one of them is needed for color comparison with the ring. Most of the ring material is concentrated within an annulus ranging between 1.72 Rj and 1.81 Rj (+/- 0.01 Rj), where Rj is the Jovian radius. With a K magnitude of 12.2 mag, Amalthea is a relatively bright satellite orbiting just outside the Jovian ring. Because of Amalthea's brightness we also require that Amalthea does not fall within the narrow annulus of the ring that exhibits enhanced column densities. Spider-diffracted light from the nearby planet should not coincide with the ring plane. Ideally we would like this pattern to be tilted by about 45 degree with respect to the ring plane. In practice, we request the maximum off-nominal roll of 23 to 25 degrees, in order to get as far away as possible from an orientation where the U3 axis is in-line with the ring plane. *** I M P O R T A N T N O T E 1 *** RPS2 cannot handle our catalogue of constraints. Therefore pointing and detailed observing intervals have to be generated with the PERCY software package. We stress that the complete submission of this proposal consists of this RPS2 template PLUS PERCY file(s). See also comments under section "Additional_Comments". Real Time Justification ----------------------- These observations are TIME CRITICAL in two respects. (1) The requirement that the Jovian ring-plane be nearly edge-on as seen from the Earth sets a global time constraint. The requirement that the ring thickness should not greatly exceed the pixel size of 0.075 arcsec places our observations between September 12, 1997 and October 31. Within this window we prefer the earliest possible observation, as both the angular scale and surface brightness of the ring decrease with time. (2) The availability or absence of certain satellites as listed above results in additional constraints within the general window (1). RPS2 cannot handle this extensive catalogue of geometrical requirements and we were forced to use PERCY procedures (see also comments under "Additional_Comments"). Calibration Justification ------------------------- During the science exposures we need Metis and/or Adrastea in the field of view for comparison purposes, since no reliable color information has been obtained for these faint satellites by means of ground-based telescopes. Both satellites have short orbital periods and have to be considered fast moving objects. It is important that one of the two satellites stays in the field of view during the entire visit. Ideally we like to have both in the field of view and Amalthea somewhere at the edge so that it doesn't occult any part of the Jovian ring. The choice of the ansa is set only by schedulability and the availability of the satellites. If there is a choice between eastern and western ansa we prefer the sunward, i.e. western ansa. It is important that during the entire program the same part of the ring is observed. We added dark frames needed to calibrate our science program. Darks can be obtained while HST is in occultation. The current PERCY program that is attached to this RPS2 template does not discard time windows that are impractical because of bright background objects that happen to be in the NIC2 field of view (H < 8 mag and no extended object that extends over several arcseconds). Additional Comments ------------------- This template is complemented by PERCY files 7241-WEST.PER and 7241-EAST.PER. In each of these PERCY files the target position is defined by TARGET and the acceptable time intervals are stored in window OBSERVING-WINDOW. If the western ansa is not schedulable (7241-WEST.PER) then use eastern ansa (7241-EAST.PER). Note that we want to observe only one ansa, preferentially the western ansa. A detailed description of the positioning can be found in corresponding PERCY file 7241-WEST.PER (or 7241-EAST.PER). ------------------------------------------------------------------------------------ 7241( 15) - 09/26/97 15:07 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: Rodger I. Thompson,*University of Arizona,*Steward Obs./NICMOS,*933 N. Cherry Ave,*Tucson, AZ 85721-0065 Ship Via: Email: thompson@as.arizona.edu ------------------------------------------------------------------------------------ 7241( 15) - 09/26/97 15:07 - [ 4] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: JUPITER-RING-E ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: RING JUPITER ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=JUPITER | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | F-CONT(11000)=4.0+/-1.0e-16 | Target 1 defines where the center of F-CONT(16000)=4.0+/-1.0e-16 | camera NIC2 is located. In PERCY F-CONT(20500)=3.2+/-0.7e-16 | routine 7241-*.PER target 1 K = 16.5+/-1.5 | corresponds to position labeled K = 15.1+/-1.5 | TARGET. *** I M P O R T A N T N O T | E 2 *** In the current RPS2 template | the western ansa is implemented and | PERCY routine 7241-WEST.PER has to | be used. If the observations are not | schedulable try with alternative set | (PERCY file 7241-EAST.PER) and | replace ANG by ANG = 71.55. NICMOS | camera 2 is placed such that no part | of the field of view is closer than | 3 arcseconds to the jovian limb. A | roll of 23 - 25 degrees orients | diffraction patterns at an angle | different from the orientation of | the ring plane. Io, Europa, | Ganymede, and Callisto have to be | outside the field of view of NICMOS | camera 2 which is 19.2 arcseconds | wide with a semi-diagonal of ca. | 13.6 arcseconds. Adrastea and/or | Metis need to be inside the field of | view. Amalthea is not allowed to | occult the thick annulus of the ring | which is located at a distance | between 1.72 Rj and 1.81 Rj from | Jupiter (Rj = 1 Jovian radius). *** | I M P O R T A N T N O T E 3 *** No | "Window" options have been supplied | since RPS2 does not support our | program. Consult respective PERCY | file that contains all of the | information that usually comes with | field "Window". Also note that one | should use the positions given in | the PERCY files rather than the | positions given in this template | (though they should be the same). | 7241( 15) - 09/26/97 15:07 - [ 5] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ Acquisition Uncertainty: 0.5 " | ------------------------------------------------------------------------------------------------------------------------------------ 7241( 15) - 09/26/97 15:07 - [ 6] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: JUPITER-RING-W ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: RING JUPITER ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=JUPITER | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | F-CONT(11000)=4.0+/-1.0e-16 | Target 1 defines where the center of F-CONT(16000)=4.0+/-1.0e-16 | camera NIC2 is located. In PERCY F-CONT(20500)=3.2+/-0.7e-16 | routine 7241-*.PER target 1 K = 16.5+/-1.5 | corresponds to position labeled K = 15.1+/-1.5 | TARGET. *** I M P O R T A N T N O T | E 2 *** In the current RPS2 template | the western ansa is implemented and | PERCY routine 7241-WEST.PER has to | be used. If the observations are not | schedulable try with alternative set | (PERCY file 7241-EAST.PER) and | replace ANG by ANG = 71.55. NICMOS | camera 2 is placed such that no part | of the field of view is closer than | 3 arcseconds to the jovian limb. A | roll of 23 - 25 degrees orients | diffraction patterns at an angle | different from the orientation of | the ring plane. Io, Europa, | Ganymede, and Callisto have to be | outside the field of view of NICMOS | camera 2 which is 19.2 arcseconds | wide with a semi-diagonal of ca. | 13.6 arcseconds. Adrastea and/or | Metis need to be inside the field of | view. Amalthea is not allowed to | occult the thick annulus of the ring | which is located at a distance | between 1.72 Rj and 1.81 Rj from | Jupiter (Rj = 1 Jovian radius). *** | I M P O R T A N T N O T E 3 *** No | "Window" options have been supplied | since RPS2 does not support our | program. Consult respective PERCY | file that contains all of the | information that usually comes with | field "Window". Also note that one | should use the positions given in | the PERCY files rather than the | positions given in this template | (though they should be the same). | 7241( 15) - 09/26/97 15:07 - [ 7] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ Acquisition Uncertainty: 0.5 " | ------------------------------------------------------------------------------------------------------------------------------------ 7241( 15) - 09/26/97 15:07 - [ 8] Visit: 01 Visit Priority: Visit Requirements: SCHED 30% ORIENT 90D TO 97D BETWEEN 12-SEP-97 AND 31-OCT-97 On Hold Comments: Additional Comments: I M P O R T A N T: Pointing and acceptable time windows between September 12, 1997 and October 31, 1997 are defined by PERCY routine 7241-WEST.PER (or 7241-EAST.PER) and not by this RPS2 template. See "Observing_Description" for details. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 JUPITER-RIN NIC2 MULTIAC NIC2-FI F110W 1.100 SAMP-SEQ = STEP8,NSAMP = 11 6 DEF G-E CUM X Comments: Estimated signal to noise for ring is 20 using one MULTIACCUM sequence. Exposure is not read noise limited. Total S/N is 48 for 6 MULTIACCUM sequences. Amalthea, if in the field of view, saturates after an exposure of 13 s. ------------------------------------------------------------------------------------------------------------------------------------ 2 JUPITER-RIN NIC2 MULTIAC NIC2-FI F160W 1.600 SAMP-SEQ = STEP8,NSAMP = 11 7 DEF G-E CUM X Comments: Estimated signal to noise for ring is 20 using one MULTIACCUM sequence. Exposure is not read noise limited. Total S/N is 52 for 7 MULTIACCUM sequences. Amalthea, if in the field of view, saturates after an exposure of 30 s. ------------------------------------------------------------------------------------------------------------------------------------ 3 JUPITER-RIN NIC2 MULTIAC NIC2-FI F205W 2.050 SAMP-SEQ = STEP64,NSAMP = 10 12 DEF G-E CUM X Comments: Estimated signal to noise for ring is 13 using one MULTIACCUM sequence. Exposure is not read noise limited. Total S/N is 48 for 13 MULTIACCUM sequences. Amalthea, if in the field of view, saturates after an exposure of 32 s. ------------------------------------------------------------------------------------------------------------------------------------ 7241( 15) - 09/26/97 15:07 - [ 9] Visit: 02 Visit Priority: Visit Requirements: SCHED 30% ORIENT 90D TO 97D BETWEEN 12-SEP-97 AND 31-OCT-97 On Hold Comments: Additional Comments: I M P O R T A N T: Pointing and acceptable time windows between September 12, 1997 and October 31, 1997 are defined by PERCY routine 7241-WEST.PER (or 7241-EAST.PER) and not by this RPS2 template. See "Observing_Description" for details. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 JUPITER-RIN NIC2 MULTIAC NIC2-FI F110W 1.100 SAMP-SEQ = STEP8,NSAMP = 11 6 DEF G-W CUM X Comments: Estimated signal to noise for ring is 20 using one MULTIACCUM sequence. Exposure is not read noise limited. Total S/N is 48 for 6 MULTIACCUM sequences. Amalthea, if in the field of view, saturates after an exposure of 13 s. ------------------------------------------------------------------------------------------------------------------------------------ 2 JUPITER-RIN NIC2 MULTIAC NIC2-FI F160W 1.600 SAMP-SEQ = STEP8,NSAMP = 11 7 DEF G-W CUM X Comments: Estimated signal to noise for ring is 20 using one MULTIACCUM sequence. Exposure is not read noise limited. Total S/N is 52 for 7 MULTIACCUM sequences. Amalthea, if in the field of view, saturates after an exposure of 30 s. ------------------------------------------------------------------------------------------------------------------------------------ 3 JUPITER-RIN NIC2 MULTIAC NIC2-FI F205W 2.050 SAMP-SEQ = STEP64,NSAMP = 10 12 DEF G-W CUM X Comments: Estimated signal to noise for ring is 13 using one MULTIACCUM sequence. Exposure is not read noise limited. Total S/N is 48 for 13 MULTIACCUM sequences. Amalthea, if in the field of view, saturates after an exposure of 32 s. ------------------------------------------------------------------------------------------------------------------------------------ 7241( 15) - 09/26/97 15:07 - [ 10] Summary Form for Proposal 7241 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations NIC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SAMP-SEQ = STEP8 NSAMP = 11 NSAMP = 10 SAMP-SEQ = STEP64 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GTO/NIC ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SCHED 30% ORIENT 90D TO 97D BETWEEN 12-SEP-97 AND 31-OCT-97 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W F160W F205W ------------------------------------------------------------------------------------------------------------------------------------ Target Names JUPITER-RING-E JUPITER-RING-W ------------------------------------------------------------------------------------------------------------------------------------