| DATA_SET_DESCRIPTION |
Data Set Overview
=================
IAU-adopted magnitude parameters (absolute V magnitude and slope
parameter) for all numbered asteroids.
The absolute magnitude is variously given to 0.01, 0.1, or 1.0 mag
precision, depending on the accuracy and consistency of the data used
to arrive at the value.
Those slope parameters that were determined by fitting the IAU-adopted
phase function (see Bowell et al. 1989 [BOWELLETAL1989]) to data are
given an origin code letter of 'f' (for 'fitted'); all others are
given a code letter of 'a' (for 'assumed'). The default value is 0.15
in all cases. Note that because most absolute magnitudes are based on
apparent magnitudes measured at non-zero phase angles, the value of
the absolute magnitude does depend on the assumed value for the slope
parameter. A change in the assumed value of the slope parameter
(based on a taxonomic classification, for example) should not be made
independently of the absolute magnitude.
'MPC' in the reference field stands for 'Minor Planet Circular',
published on behalf of Commission 20 of the International Astronomical
Union by the Minor Planet Center, Smithsonian Astrophysical
Observatory, Cambridge, MA 02138.
This version of the dataset contains magnitude parameters for all
asteroids numbered as of the 1999 February 2 batch of Minor Planet
Circulars and includes 9999 entries. The absolute magnitude database
underwent a major revision during the past year, with updated values
being published on Minor Planet Circulars 28104 through 28116. Known
errors were corrected at that time, and magnitude parameters that had
been taken from the literature for previous versions of the PDS
database became formally adopted. Nevertheless, a pointer to the
original reference for those magnitude parameters has been retained in
the note field. Although the updated list as published in the Minor
Planet Circulars includes values for all asteroids numbered as of that
time, many were not changed from the previously published list. For
purposes of this database, unchanged magnitude parameters retain their
original reference, which should make it easier for the user to
determine which have been updated.
References: Bowell, E., B. Hapke, D. Domingue, K. Lumme,
J. Peltoniemi and A.W. Harris, Application of photometric
models to asteroids, In Asteroids II (R. P. Binzel, T.
Gehrels, and M.S. Matthews, Eds.), pp. 524-556, Univ. of
Arizona Press, Tucson, 1989 [BOWELLETAL1989]
Spencer, J.R., L.A. Akimov, C. Angeli, P. Angelini, M.A.
Barucci, P. Birch, C. Blanco, M. Buie, A. Caruso, V.G.
Chiornij, F. Colas, P. Dentchev, M.C. De Sanctis, E.
Dotto, M. Fulchignoni, S. Green, A. Harris, T. Hudecek,
A.V. Kalashnikov, V.V. Kobelev, V.P. Kozhevnikov, Y.
Krugly, D. Lazzaro, J. Lecacheux, J. MacConnell, T.
Michalowski, R.A. Mohamed, B. Mueller, T. Nakamura, C.
Neese, W. Osborn, P. Pravec, D. Riccioli, V. Shevchenko,
D. Tholen, F. Velichko, C. Venditti, R. Venditti, W.
Wisniewski, J. Young, and B. Zellner, The lightcurve of
4179 Toutatis: Evidence for complex rotation. Icarus 117,
71-89, 1995 [SPENCERETAL1995].
Modification History
====================
The astermag data set was first introduced into PDS at the April 1993
asteroid data sets review. It has subsequently been updated at the
March 1995, March 1996, and April 1999 asteroid data sets reviews.
The updates consist of adding additional data which have become
available since the previous update.
Parameters
==========
The data file contains one entry for each numbered asteroid, and each
entry includes fields for the following parameters. Asteroid catalog
number, absolute V magnitude, slope parameter, a code for the origin
of the slope parameter, the reference for the data, and a note flag.
Data
====
The data are presented in a single ASCII data table, 'astermag.tab'.
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