PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 78 FILE_RECORDS = 850 ^TABLE = "SI_G_1.TAB" DATA_SET_ID = "GO-J-NIMS-4-ADR-SL9IMPACT-V1.0" SPACECRAFT_NAME = GALILEO_ORBITER MISSION_PHASE_NAME = "SHOEMAKER-LEVY 9 ENCOUNTER" TARGET_NAME = JUPITER OBSERVATION_NAME = SLJNFRAGMG01 NOTE = "NIMS observation of impact of G fragment of comet Shoemaker-Levy 9 with Jupiter. // Source intensities versus time for the S-L 9 G fragment Jupiter impact site. Chi squared minimization was used for the fireball period to find the fraction (eta) of reflected light to subtract to obtain the best fit of a blackbody spectrum. A regression fit of eta to detector 1 was developed from the fireball period and applied to the pre- and post-fireball periods." START_TIME = 1994-199T07:02:26Z STOP_TIME = 1994-199T07:13:11Z SPACECRAFT_CLOCK_START_COUNT = 2486477.17 SPACECRAFT_CLOCK_STOP_COUNT = 2486487.74 PRODUCT_ID = "SI_G_1.TAB" PRODUCT_CREATION_TIME = 1995-11-19 INSTRUMENT_NAME = "NEAR INFRARED MAPPING SPECTROMETER" INSTRUMENT_ID = NIMS INSTRUMENT_MODE_ID = FIXED_MAP GAIN_MODE_ID = 2 CHOPPER_MODE_ID = 'REFERENCE' START_GRATING_POSITION = 2 OFFSET_GRATING_POSITION = 4 GRATING_POSITION_INCREMENT = 0 GRATING_POSITIONS = 1 OBJECT = TABLE INTERCHANGE_FORMAT = ASCII ROWS = 850 COLUMNS = 11 ROW_BYTES = 78 OBJECT = COLUMN NAME = ITEM_NUMBER DESCRIPTION = "Consecutive item number, beginning at 1, of NIMS mirror scan crossings of Jupiter included in this table" DATA_TYPE = INTEGER START_BYTE = 1 BYTES = 3 END_OBJECT = COLUMN OBJECT = COLUMN NAME = CROSSING_NUMBER DESCRIPTION = "As the spacecraft scan platform scanned across Jupiter's position, the impact site (the morning hemisphere) was generally contained within one, and sometimes two, NIMS mirror scans. For each scan, two pixels are illuminated, due to overlap in the spatial response. The 'crossing number' identifies each scan: even crossing numbers correspond to night to dayside scans, odd numbers the reverse. Some crossings are missing due to transmission problems or instrument cycling or limited playback time. Occasionally the same crossing will appear twice, due to overlap in the scan platform scan pattern. In some cases, the signal is clearly weaker due to decreased responsivity at the edge of the field, but is retained for relative spectral information." DATA_TYPE = INTEGER START_BYTE = 5 BYTES = 4 END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPACECRAFT_CLOCK_COUNT_RIM DESCRIPTION = "The Spacecraft Clock Realtime IMage count (RIM) of the current record. The RIM count is incremented every 60 2/3 seconds. It contains 91 minor frames or MOD91 counts." DATA_TYPE = INTEGER START_BYTE = 10 BYTES = 8 END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPACECRAFT_CLOCK_COUNT_MOD91 DESCRIPTION = "The Spacecraft Clock MOD91 count (minor frame) of the current record. The MOD91 count is incremented every 2/3 second, and assumes 91 values, 0 to 90, within each RIM. Since there are two mirror scans per minor frame, and Jupiter appears in the center of the scan, .25 or .75 has been added to the MOD91 count as appropriate." DATA_TYPE = REAL START_BYTE = 19 BYTES = 6 END_OBJECT = COLUMN OBJECT = COLUMN NAME = EARTH_RECEIVED_TIME DESCRIPTION = "The Earth Received Time is the time at which the event would have been observed on Earth. It is in seconds relative to 1994 day 199, 07:33:32 UT, which corresponds to spacecraft clock RIM 2486478, MOD91 count 67.99." UNIT = SECOND DATA_TYPE = REAL START_BYTE = 26 BYTES = 8 END_OBJECT = COLUMN OBJECT = COLUMN NAME = JUPITER_REFERENCE_FRACTION DESCRIPTION = "The Jupiter reference fraction (eta) is the fraction of the Jupiter reference subtracted from the dark corrected data numbers. It is the best fit of a blackbody for the continuum wavelengths (1.84, 2.67, 2.99 and 4.38 microns), minimizing chi-squared over approximately 60 seconds of fireball phenomena. A regression fit of eta to detector 1 was developed from the fireball period and applied to the pre- and post-fireball periods. We use the weighted mean of the full disc Jupiter reference values here; very little difference in derived fireball temperatures was found using the morning hemisphere G reference spectra." UNIT = DIMENSIONLESS DATA_TYPE = REAL START_BYTE = 35 BYTES = 6 END_OBJECT = COLUMN OBJECT = COLUMN NAME = DETECTOR_NUMBER DESCRIPTION = "NIMS detector (of 17). Only data from those detectors found useful so far (6-15) have been included in this table." DATA_TYPE = INTEGER START_BYTE = 42 BYTES = 3 END_OBJECT = COLUMN OBJECT = COLUMN NAME = WAVELENGTH DESCRIPTION = "Wavelength of NIMS detector" DATA_TYPE = REAL UNIT = MICROMETER START_BYTE = 46 BYTES = 7 END_OBJECT = COLUMN OBJECT = COLUMN NAME = LOWER_LIMIT_SOURCE_INTENSITY DESCRIPTION = "Lower limit of source intensity, the power radiated per unit solid angle and per micron, expressed as Terawatts per steradian-micron. (See next column for algorithm.) The error estimate includes the intrinsic noise of the instrument and pointing-induced variations within a spectrum. Variations in overall intensity level are not included." DATA_TYPE = REAL UNIT = 'TWATT*SR**-1*uM**-1' START_BYTE = 54 BYTES = 7 END_OBJECT = COLUMN OBJECT = COLUMN NAME = BEST_ESTIMATE_SOURCE_INTENSITY DESCRIPTION = "Best estimate of source intensity, the power radiated per unit solid angle and per micron, expressed as terawatts per steradian-micron. It is computed by (1) dark-correcting and summing sensor values from the two successive mirror positions containing the signal and multiplying by the instrumental sensitivity, (2) similarly dark-correcting the weighted mean Jupiter reference spectrum (from JREF_DNS.TAB) and normalizing it to detector 1, (3) subtracting the fraction eta of the Jupiter reference from the sensed results, (4) correcting the results for cloud reflection and (5) putting them into source intensity units." DATA_TYPE = REAL UNIT = 'TWATT*SR**-1*uM**-1' START_BYTE = 62 BYTES = 7 END_OBJECT = COLUMN OBJECT = COLUMN NAME = UPPER_LIMIT_SOURCE_INTENSITY DESCRIPTION = "Upper limit of source intensity, the power radiated per unit solid angle and per micron, expressed as Terawatts per steradian-micron. (See previous column for algorithm.) The error estimate includes the intrinsic noise of the instrument and pointing-induced variations within a spectrum. Variations in overall intensity level are not included." DATA_TYPE = REAL UNIT = 'TWATT*SR**-1*uM**-1' START_BYTE = 70 BYTES = 7 END_OBJECT = COLUMN END_OBJECT = TABLE END