Data Set Overview
  =================
  This is a compilation of published rotational parameters for lightcurve data
  on asteroids, based on the Warner et al. (2009) Asteroid Lightcurve
  Database.  This is the version released on March 1, 2014.  These data files
  are provided by Alan Harris (MoreData!), Brian D. Warner (Palmer Divide
  Observatory/MoreData!), and Petr Pravec, (Astronomical Institute, Czech
  Republic).

  The compilation is originally based on that published in Lagerkvist et al.
  (1989).


  Parameters
  ==========

  The data files included are listed here with a description of their
  contents.

  lcsummary.tab -
  The summary file includes one entry for each asteroid for which lightcurve
  observations have been made.  Each entry gives the following parameters:
  rotation period; minimum and maximum amplitude of lightcurve; reliability
  code; and a flag for binarity.  These parameters are selected as the best
  values known from the published literature.

  lcdetails.tab -
  The details file includes one entry for each publication of asteroid
  lightcurve results, with the same parameters as in the summary file but
  extracted from the individual publications.  There is a reference code
  referring to the publications list (lc_references.tab).

  lc_binary.tab -
  A list of asteroids known or suspected to be binary, along with the reported
  primary and secondary periods and amplitudes.  Primary and secondary periods
  correspond with the rotation period of the primary and the orbital period of
  the binary.  Note that not all binaries listed are based on lightcurve
  studies, the list also includes adaptive optics and radar studies.  An
  independent compilation of information on binary asteroids may be found in
  another PDS data set, the Binary Minor Planets Summary,
  EAR-A-COMPIL-5-BINMP.

  lc_npa.tab -
  A list of asteroids for which non-principal-axis (NPA) data have been
  reported, along with the reported primary and secondary periods and
  amplitudes.

  lc_references.tab -
  This file includes the complete citation for each reference cited in the
  data files.  It also contains the BibCode of the reference.

  lc_spinaxis.tab -
  A list of asteroids for which spin axis determinations have been published.
  Includes published pole solutions plus a synthesis entry for each asteroid.

  Amplitudes quoted in these files are the difference between maximum and
  minimum light, with some accounting for noise in the data.


  Documentation
  ==========

  The file readme.asc, included in the document directory, contains a
  description of the data files and how they were compiled.  The readme file
  was released with the full distribution of the Asteroid Lightcurve Database,
  including a few files not included in the PDS archive.  The Ambiguous
  Periods file was removed by the 2008 PDS review panel on the grounds that it
  is of marginal utility.  The detailed binary asteroid files maintained by
  Petr Pravec, although part of the Asteroid Lightcurve Database, have not
  been supplied to us and are thus not included.

  Since the data files have been reformatted to conform to PDS requirements,
  the byte counts in the detailed format descriptions in readme.asc may not
  match the files.  The order of the columns has not been changed.  The file
  readme.asc has not been edited by PDS except to adjust the format to conform
  to PDS requirements.


  Modification History
  ====================
  The lc data set was first introduced into PDS at the April 1994 asteroid
  datasets review.  It was subsequently updated at the March 1996 review, the
  April 1999 review, the May 2002 review, the May 2004 review, and the June
  2005 review.  Updates consist of adding information published or released
  since the last update.

  At the May 2002 review of version 5.0, it was decided to separate the
  reference number listings, which were becoming long, from the main data
  table. The lccross.tab file was created to provide the cross-listing
  information between objects and references. The reference list in the main
  data file was replaced with a single number indicating the total number of
  references for each object.

  For the May 2007 review, the compilers of this data set (Harris, Warner, and
  Pravec) had loaded the data into a database and were able to provide the
  data files in a slightly updated and more uniform format.  The lcscross.tab
  crosslisting file is no longer needed, since each line in lcdetails.tab is
  tied to its appropriate reference through the lc_references.tab file.  The
  entries in the other data files also each cite a specific reference in
  lc_references.tab.

  The data set was subsequently updated in 2008 with the addition of data
  published through February 2008.  In the 2008 version the spin axis
  compilation was removed from the data set because it is a subset of the spin
  axis compilation of Kryszczynska which is included in a separate data set.
  The ambiguous periods compilation was also not included because reviewers
  considered it to have marginal value in the permanent archive.  The data set
  has subsequently been updated in the same form in 2010, 2011, 2012, and
  2014.

  In the version of 2011 and subsequent versions, the spinaxis file has been
  restored because it is more complete than the previously archived spin axis
  compilation.

  References
  ==========

  Lagerkvist, C.-I., A.W. Harris, and V. Zappala, Asteroid lightcurve
  parameters.  In 'Asteroids II', Binzel, R.P., T.  Gehrels, and M.S.
  Matthews, Eds.  (University of Arizona Press:  Tucson) p. 1162, 1989.

  Warner, B.D., A.W. Harris, and P. Pravec, The asteroid lightcurve database,
  Icarus 202, 134-146, doi:10.1016/j.icarus.2009.02.003, 2009.

Confidence Level Overview
  =========================
  The confidence level of each entry in the data set is indicated by a quality
  code.  This quality code is described in the associated data label,
  'lc_summary.lbl'.  For further information the user is referred to the cited
  original publications.

  As noted in Warner et al. (2009, Icarus 202, 134-146), only those objects
  with a U code of 2- or greater in the LC_SUMMARY file, i.e., U = 2-, 2, 2+,
  3-, or 3, should be used for rotational rate studies and, unless there is a
  specific reason otherwise, the summary line period should be used instead of
  one of the periods in the details table.