| 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 ne 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) MISSING.TAB - contains a summary of those asteroids which were
(Excluded) 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, 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. While
part of the original IRAS Minor Planet Survey
release, this file has not been ingested in the
PDS because of internal inconsistencies between
the data columns and their documented
descriptions. The internal inconsistencies are
being cleared and the file will be included in
the next release.
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, FP107, and FP108.
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