Data Set Information
DATA_SET_NAME IRAS MINOR PLANET SURVEY ASTEROIDS V5.0
DATA_SET_ID IRAS-A-FPA-3-RDR-IMPS-V5.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : The data presented with this data set include: 1) SIGHTING.TAB - contains a listing of 8210 individual sightings associated with 2004 asteroids. SIGHTING.TAB contains the observation index, the identification of asteroids sighted, information pertaining to observation times, positional information on the observations of asteroids detected, geometric albedos, diameters and their associated uncertainties, input values used in the calculations of the geometric albedos and diameters using the asteroid standard thermal model, the observed flux densities in each band, detector crossing information, correlation coefficients, and status flags for reduction steps. 2) DIAMALB.TAB - contains averaged radiometric diameters and geometric albedos derived from individual observations for 1796 numbered asteroids and 88 unnumbered asteroids (as of 1983) whose orbital elements were determined using astrometry from two or more apparitions. 3) SINGLE.TAB - contains an entry for each of 120 asteroids for which there is an accepted sighting, but in one band only. This file includes the absolute visual magnitude of the asteroid, the albedo and diameter derived from the measurement and their associated uncertainties, and the accepted status word. 4) GRNDDAT.TAB - contains entries for each of 4677 numbered asteroids and 2632 unnumbered asteroids (as of 1985) for which associations were sought in the IRAS data. Asteroids 719 Albert and 878 Mildred were still lost as of 1985 and are not included. These entries include an initial estimate of geometric albedo and diameter used in processing IRAS survey observations of asteroids, the adopted taxonomic classification, and the orbital elements at three epochs. The Julian dates of the epochs are 2445400.5, 2445500.5, and 2445600.5. For further information regarding these data see Tedesco, et. al., 1992 [TEDESCOETAL1992]. 5) IMPSSTAT.TAB - contains a summary of the number of times each asteroid was predicted to be scanned, and possible reasons for any failure to be detected. It contains entries for each of 4677 numbered asteroids and 2632 unnumbered asteroids (as of 1985) for which associations were sought in the IRAS data. Asteroids 719 Albert and 878 Mildred were still lost as of 1985 and are not included. These entries include the number of predicted sightings, number of accepted sightings, number of rejected sightings, number of missed predicted sightings, number of missed predicted faint sightings, number of dead 25 micron detector non-detections, number of noisy 25 micron detector non-detections, number of missed predictions in the galactic center region, and other non-detections. 6) REJECT.TAB - summarizes the number of rejected sightings for each asteroid and possible reasons for rejection. 7) MISSED.TAB - contains a summary of those asteroids which were predicted to pass across the IRAS focal plane during survey mode, but which generated no accepted associations. Entries include the number of times an asteroid was predicted to be scanned but was missed, and the derived greatest lower limit on the albedo and least upper limit on the diameter, plus a status word detailing the circumstances of the observation failure. 8) STMODEL.TAB - contains the flux look-up table used to generate the IMPS albedos. This table was provided by L. Lebofsky and was derived from the IRAS standard thermal model. In the original release of the IMPS data products, a number of 'derived status word (ADSTAT)' bits were always set to zero (flag not set), and have been excluded here, these were: ADSTAT 1 - All bands. Not used. Always zero. ADSTAT 2 - All bands. Not used. Always zero. ADSTAT 3 - All bands. Not used. Always zero. ADSTAT 5 - All bands. Not used. Always zero. ADSTAT 6 - All bands. Not used. Always zero. ADSTAT 7 - 100 micron band. No albedos derived from individual observations in this band were rejected from the final average using Chauvenet's criterion, therefore this flag was always set to zero for this band in this datafile. ADSTAT 8 - 25 micron band. The albedo calculation for each observation converged within 100 iterations, therefore this flag was always set to zero for this band in this datafile. In the original released IMPS data product, the bits in the ADSTAT word were ordered from right to left. A number of 'confusion status word (ASTCST)' bits were also always set to zero (flag not set), and have been excluded here, these were: ASTCST 5 - Set after hours-confirmation. Since sightings detections are only seconds-confirmed, this flag is always set to zero. ASTCST 6 - Set after hours-confirmation. Since sightings detections are only seconds-confirmed, this flag is always set to zero. ASTCST 7 - Set to 1 when an analog to digital saturation flag was set due to a bright source saturating at least one detector in this band. No such events in IMPS in any band. ASTCST 8 - Not used. Always zero. In addition, a number of 'asteroid status word (ASTATW)' bits were always set to zero (flag not set) or one (flag set) and have been excluded here, these were: ASTATW 5 - WSDB MCON position match. All MCON (WSDB 'weeks' or months confirmed) asteroid sightings are rejected by IMPS. These sightings are likely to be confused with stationary background sources (e.g. molecular clouds, galaxies, knots of infrared cirrus). See ASTATW 9. No accepted detections had flag set. ASTATW 8 - IMPS asteroid association. Set to unity for every accepted asteroid sighting, therefore the flag is always one in this file by definition. ASTATW 9 - Point Source Ver. 2 match. All asteroid sightings confused with sources in the IRAS Point Source Catalog are rejected by IMPS. This is a subset of ASTATW 5. ASTATW 10 - Detections only by small detectors on the outer edge of the focal plane array. No accepted detections had this flag set. ASTATW 11 - Predicted flux < 0.14 Jy. Set a priori for all candidate associations of an IMPS asteroid if no predicted flux density at 25 microns is greater than 0.14 Jansky. No detections were accepted when this flag was set. ASTATW 16 - 100 micron albedo used in the final average albedo. Since no 100 micron detections contribute to derived IMPS average values, this flag is never set. ASTATW 17 - Faint Source Version 2 match. All asteroid sightings confused with sources in the IRAS Faint Source Survey are rejected by IMPS (See MOSHIRETAL1992), therefore this flag is always zero in this data file. ASTATW 20 - Serendipitous Version 1 match. All asteroid sightings confused with sources in the IRAS Serendipitous Survey Catalog are rejected by IMPS (See KLEINMANETAL1986), therefore this flag is always set to zero in this data file. ASTATW 29 - Not used. Always zero. ASTATW 31 - 2+ sightings match. Set if more than one source is associated with a single asteroid prediction and therefore rejected by IMPS. No detections were accepted in this file when this flag was set. ASTATW 32 - Not used. Always zero. Modification History : The IMPS data set was ingested in 1994 and updated to correct a minor error in 1995. These versions included only FP102, the diameters and albedos. The data set has now been updated to include FP103, FP104, FP105, FP 106, FP107, FP108, and the flux lookup table used tto generate the IMPS albedos. As part of a general review of archive data in Feb 2002, the labels and data files were examined and the following changes made: o Numbers were provided for all asteroids numbered as of 15 Jan 2002. Numbers were found by referencing Ted Bowell's cross-identification database, as incorporated into the Small Bodies Data Base of the PDS Small Bodies Node (SBN). Provisional identifications from the original IMPS files were retained for cross-referencing. o Names were provided for all asteroids named as of 02 Feb 2002. Names were gathered from the list provided by the Minor Planet Center at this URL: http://cfa-www.harvard.edu/iau/lists/MPNames.html o All files listing asteroid observations except 'sighting.tab' were re-sorted on asteroid number. Asteroids identified only by provisional designation are located at the bottom of the files, sorted by provisional ID. The 'sighting.tab' file was and is sorted on sightings index number. o Minor errors were corrected as found (e.g., the wrong value for 'COLUMNS' was found in two labels; incorrect 'START_BYTE' values were found in another). o Potentially confusing references to 'FPA.LBL', a file from a different data set, were replaced by a reference to the appropriate PDS DATA_SET_ID. o Cosmetic changes were made to bring labels and catalog files into conformance with current PDS/SBN standards and practices. o Documentation found in some of the labels regarding status words which were systematically excluded from more than one of the data files was extracted from those labels and incorporated into the information above.
DATA_SET_RELEASE_DATE 1998-03-23T00:00:00.000Z
START_TIME 1983-01-01T12:00:00.000Z
STOP_TIME 1983-11-01T12:00:00.000Z
MISSION_NAME INFRARED ASTRONOMICAL SATELLITE
MISSION_START_DATE 1983-01-26T12:00:00.000Z
MISSION_STOP_DATE 1983-11-23T12:00:00.000Z
TARGET_NAME ASTEROID
TARGET_TYPE ASTEROID
INSTRUMENT_HOST_ID IRAS
INSTRUMENT_NAME FOCAL PLANE ARRAY
INSTRUMENT_ID FPA
INSTRUMENT_TYPE CAMERA
NODE_NAME Small Bodies
ARCHIVE_STATUS SUPERSEDED
CONFIDENCE_LEVEL_NOTE Review : This version of the data set underwent peer review on May 10, 2002.
CITATION_DESCRIPTION Sykes M.V., T.L. Brown, and A.C. Raugh, IRAS MINOR PLANET SURVEY ASTEROIDS V5.0, IRAS-A-FPA-3-RDR-IMPS-V5.0, NASA Planetary Data System, 1998.
ABSTRACT_TEXT Derived diameters and albedoes of asteroids, plus associated data on sighting and non-sightings, extracted from the IRAS archives.
PRODUCER_FULL_NAME MARK SYKES
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