Summary of the Kepler Input Catalog Format

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These notes are relevant for Version 10 of the Kepler Input Catalog.

Release History
Schema for Latest Release
Schema for CATKEY Database
Schema for SCPKEY Database
Source of Astrometry
Source of KEPMAG for Stars not Observed by the SCP



Release History

   Version     Approx Date   Comments
      10       12 Aug 2008   Final mags and values from SCP.  Final delivery
                             means KEPLER_ID now frozen and can be used as
                             identifier.  Major revision in KEPMAG algorithm.
                             Consensus is now to put "best possible" value
                             into KEPMAG.  See revised CQ discussion below.
                             Also revised PQ value (see below) to reflect
                             number of parent catalog detections since this
                             is a metric for how reliable entry might be.

       9       26 May 2008   Recompiled to incorporate latest (26 May 08)
                             SCP mags and values.  Also includes fixed
                             stellar mass calculation.  All mass values
                             in KIC8 were 1.0.  Revised culling algorithm to
                             remove more double detections and probable
                             spurious entries.  Revised ALTSOURCE algorithm
                             to retain Hipparcos and Tycho-2 values to ease
                             search for bright stars.

       8       15 Mar 2008   Recompiled to incorporate latest (2 Mar 08)
                             SCP mags and values.  Added ALTSOURCE==5 for
                             Lepine high proper motion stars and ALTSOURCE==15
                             for VLBA astrometric standards.  Also KEPMAG
                             set to NULL for all non-SCP stars as per
                             consensus of users.

               29 May 2007   Added Lepine and hooks for other catalogss

               01 May 2007   Added VLBA Astrometric Reference QSO catalog
                               as ALTSOURCE==15

       7        15 Dec 2006   Rename YBID to SCPID and revised content.  New
                              schema, content, etc., for SCPKEY database
                              as per SCP Team spectroscopy, etc.

       6        22 Feb 2006   Old KICID is now KEPLER_ID.  No effect on content.

       6         6 Jan 2006   Fixed KEPMAG for non-SCP stars

       5        29 Dec 2005   Called KIC05 as per SOC/SCP ICD.  Same
                                schema as (4). Lots more SCP data.

       4        01 Apr 2005   Recalibration of photographic magnitudes.

       3        17 Feb 2005   Added colors, fixed bugs, added documentation.
                             Should be version for Team in May 05

       2         1 Feb 2005   Astronomer units instead of integers. Added
                             PARLX, GLONG, GLAT fields.

       1        05 Jan 2005   Fixed SPD/DEC error

       0        27 Dec 2004   Dec 31 2004 release as per Requirements Document


Schema for Latest Release

olumn  DB Name      Type      Units        Format, comments, etc.
   1     RA          double     hours         Right Ascension (HH.HHHHHHH)
   2     DEC         double     degrees       Declination (sDD.DDDDDD)
   3     PMRA        float      arcsec/year   RA proper motion(sMM.MMMM)
   4     PMDEC       float      arcsec/year   Dec proper motion (sMM.MMMM)
   5     UMAG        float      magnitudes    u-band magnitude (MM.MMM)
   6     GMAG        float      magnitudes    g-band magnitude (MM.MMM)
   7     RMAG        float      magnitudes    r-band magnitude (MM.MMM)
   8     IMAG        float      magnitudes    i-band magnitude (MM.MMM)
   9     ZMAG        float      magnitudes    z-band magnitude (MM.MMM)
  10     GREDMAG     float      magnitudes    GRed band magnitude (MM.MMM)
  11     D51MAG      float      magnitudes    D51 band magnitude (MM.MMM)
  12     JMAG        float      magnitudes    2MASS J-band magnitude (MM.MMM)
  13     HMAG        float      magnitudes    2MASS H-band magnitude (MM.MMM)
  14     KMAG        float      magnitudes    2MASS K-band magnitude (MM.MMM)
  15     KEPMAG      float      magnitudes    Kepler-band magnitude (MM.MMM)
  16     KEPLER_ID   int        (none)        Unique KIC catalog ID
  17     TMID        int        (none)        Unique 2MASS catalog ID
  18     SCPID       int        (none)        Unique SCP processing ID
  19     ALTID       int        (none)        ID in other catalog (see 20)
  20     ALTSOURCE   int        (none)        Source catalog for ALTID (see 19)
  21     GALAXY      int        (none)        Star/galaxy indicator
  22     BLEND       int        (none)        Isolated/blended indicator
  23     VARIABLE    int        (none)        Constant/variable indicator
  24     TEFF        int        degrees K     Effective temperature (TTTTT)
  25     LOGG        float      cm/sec**2     LOG10 surface gravity (sL.LLL)
  26     FEH         float      solar         LOG10 Fe/H metallicity (sL.LLL)
  27     EBMINUSV    float      magnitudes    E(B-V) reddening (sM.MMM)
  28     AV          float      magnitudes    A_V extinction (M.MMM)
  29     RADIUS      float      solar         Radius (RRR.RRR)
  30     CQ          string     (none)        Source of data - see Notes
  31     PQ          int        (none)        Photometry quality indicator
  32     AQ          int        (none)        Astrophysics quality indicator
  33     CATKEY      int        (none)        Unique integer key to CATALOG DB
  34     SCPKEY      int        (none)        Unique integer key to SCP DB
  35     PARALLAX    float      arcsec        Parallax (sP.PPPP)
  36     GLON        float      degrees       Galactic longitude (DDD.DDDDDD)
  37     GLAT        float      degrees       Galactic latitude (sDD.DDDDDD)
  38     PMTOTAL     float      arcsec/year   Total proper motion (MM.MMMM)
  39     GRCOLOR     float      magnitudes    g-r color (sM.MMM)
  40     JKCOLOR     float      magnitudes    J-K color (sM.MMM)
  41     GKCOLOR     float      magnitudes    g-K color (sM.MMM)


The TYPE field shows the suggested minimum precision for storage of the value. The string in the COMMENTS field shows the format of the entry in the ASCII version of the database files.

  ALTSOURCE values:
        Value         Comments
            0        ALTID contains NULL
            1        ALTID contains Hipparcos catalog ID
            2        ALTID contains Tycho2 catalog ID
            3        ALTID contains UCAC2 catalog ID
            4        ALTID contains General Catalog of Variable Stars ID
            5        Lepine proper motion catalog star.  ALTID > 0 is 2MASS
                       id for star, < 0 is a pseudo-identifier generated
                       by SCP processing.
            6        ALTID contains 2MASS catalog ID coming from
                     Astroseismology catalog.
           11        ALTID contains NED catalog ID
           12        ALTID contains Extended 2MASS Catalog ID
           13        ALTID contains FIRST catalog ID
           14        ALTID contains NVSS catalog ID
           15        ALTID contains VLBA catalog ID
           16        ALTID contains CHANDRA catalog ID

  CQ values:
       ASCII character string indicating the source of KEPMAG value.

        Value         Meaning
        NOCAL         No calibration to optical magnitudes possible.  Used
                      for entries from non-optical catalogs.  KEPMAG field
                      is NULL.
        2MASS         Objects found only in 2MASS catalog with no optical
                      counterpart. KEPMAG field is NULL.
        UNCAL         KEPMAG copied from a single color of the parent catalog.
                      Because a color-based correction was not possible given
                      that the parent catalog entry contained only a single
                      color, the uncertainty in the KEPMAG value could easily
                      be 1.0 magnitudes or larger.
        PHOTO         The parent catalog contained a blue and red magnitude
                      obtained from photographic photometry.  These values
                      were used to compute the KEPMAG on the basis of
                          sdssg = blue;
                          sdssr = red;
                          color = sdssg - sdssr;
                          if (color <= 0.8)
                             kepmag = 0.8*sdssr + 0.2*sdssg;
                             kepmag = 0.9*sdssr + 0.1*sdssg;
                      The internal photographic magnitudes have typical
                      errors of 0.2 magnitudes, and these uncertainties
                      in combination with the approximate nature of the
                      calibration suggests that these KEPMAG errors are
                      perhaps 0.3 magnitudes or larger.
        TYBV          The parent catalog is Tycho-2, and this gives B and
                      V magnitudes.  The KEPMAG value was computed from
                             sdssg = 0.54*b + 0.46*v - 0.07;
                             sdssr = -0.44*b + 1.44*v + 0.12;
                      and the same transformation as above to compute KEPMAG.
                      The errors in KEPMAG follow those for the Tycho-2
                      catalog, being a few hundredths for brighter stars
                      and perhaps as large as a tenth for fainter ones,
                      with a few hundredths added in quadrature for the
                      uncertainty of the transformation.
        SCP           The SCP values for sdssg and sdssr were used to compute
                      KEPMAG according to the equation above.  The error
                      for KEPMAG is larger than for the in-band colors,
                      and is approximately 0.03 magnitudes.

PQ values:

Integer in the range (0 <= PQ <= 8) counting the number of different optical colors presented for this entry in the parent catalogs. For NOCAL and 2MASS entries, this value is 0. For all others, it is at least 1. The maximum value is 8 being the sum of USNO-B1.0 (O,E,J,F,N), UCAC-2 (R), and Tycho-2 (B,V). In general, the more colors in the parent catalog, the more likely that this star is real. Stars with low values (perhaps 3 or smaller) may not be real and should be verified by other means.

AQ values:

Placeholder for SCP values that have yet to be determined. Current version is value between 0-6 which is the count of non-NULL entries in TEFF, LOGG, FEH, AV, EBMINUSV, RADIUS.


Schema for CATKEY Database

 Column  DB Name      Type      Units        Format, comments, etc.

   1     CATKEY       int       (none)       Unique integer key to CATALOG DB
   2     CATFLAG      int       (none)       Bit flag from catalog merge
   3     TYCHOID      int       (none)       Original ID in Tycho-2 catalog
   4     UCACID       int       (none)       Original ID in UCAC catalog
   5     GCVSID       int       (none)       Original ID in GCVS catalog
   6     SOURCE       character (none)       STAR, XTM, NED, NVSS, FIRST
   7     SOURCEID     int       (none)       ID in original catalog
   8     FLUX1        int       (variable)   First flux in original catalog
   9     FLUX2        int       (variable)   Second flux in original catalog
  10     RAEPOCH      float     year         Epoch of RA coordinate
  11     DECEPOCH     float     year         Epoch of Dec coordinate
  12     JMAG         float     mag          2MASS J magnitude
  13     HMAG         float     mag          2MASS H magnitude
  14     KMAG         float     mag          2MASS K magnitude
  1. If the object is a star with one or more cross-identifications in the UCAC, Tycho2, or GCVS catalogs, SOURCE is set to STAR, and all cross-identifications are listed.

  2. If the object comes from a non-optical or other special catalog, SOURCE is set to the name of the catalog (XTM, NED, NVSS, FIRST) and the FLUX1 and FLUX2 are set to the fluxes listed in those catalog.

  3. All entries have non-NULL values for CATKEY, CATFLAG, and SOURCE. For STARS, there will be at least one non-NULL value in TYCHOID, UCACID, and GCVSID. For galaxies and other peculiar objects, there should be non-NULL values in SOURCEID, FLUX1, FLUX2 (depending on catalog), RAEPOCH and DECEPOCH. XTM sources will have non-NULL values in JMAG, HMAG, and KMAG.


Schema for SCPKEY Database

 Column  DB Name      Type      Units        Format, comments, etc.
   1     SCPKEY           int       (none)       Same as KIC column 34
   2     SCP_FIBER_RA     double    hours        Right Ascension (HH.HHHHHHH)
   3     SCP_FIBER_DEC    double    degrees      Declination (sDD.DDDDDD)
   4     SCP_TEFF         int       degrees      Effective temperature (TTTTT)
   5     SCP_TEFF_ERR     int       degrees      Error in SCP_TEFF (TTTTT)
   6     SCP_LOGG         float     cm/sec**2    LOG10 surface gravity (sL.LLL)
   7     SCP_LOGG_ERR     float     cm/sec**2    Error in SCP_LOGG (sL.LLL)
   8     SCP_FEH          float     solar        LOG10 Fe/H metallicity (sL.LLL)
   9     SCP_FEH_ERR      float     solar        Error in SCP_FEH (sL.LLL)
  10     SCP_VSINI        float     km/sec       Rot. V*SIN(incl) (kkkk.kk)
  11     SCP_VSINI_ERR    float     km/sec       Error in SCP_VSINI (kkkk.kk)
  12     SCP_RV           float     km/sec       Radial Velocity (skkkk.kk)
  13     SCP_RV_ERR       float     km/sec       Error in SC_RV (kkkk.kk)
  14     SCP_CCPH         float     (none)       Cross correlation peak (p.ppp)

  1. SCPKEY database contains values determined by spectroscopy as differing from photometry.

  2. Values for any or all columns in SCPKEY database need not agree with values listed in KIC. In particular, the SCP_FIBER_RA and SCP_FIBER_DEC refer to the focal plane position of the spectrograph fibers, and are not the catalog positions for the stars.

  3. Extended discussion and documentation for the values in the SCPKEY database are provided in the written summaries of the SCP, and are not repeated here.


Source of Astrometry (RA, DEC, PMRA, PMDEC, PARALLAX)

The source of the astrometric quantities depends on which catalog (or catalogs) contain data for this star. To ensure the highest accuracy and to minimize systematic errors, the hierarchy for the choice of astrometric values is as follows

  1. SCP (50 milliarcseconds, but closer to Kepler epoch)

  2. Hipparcos (10 milliarcseconds)

  3. Tycho-2 for V brighter than 8.0 (20 milliarcseconds)

  4. UCAC2 (40 milliarcseconds)

  5. 2MASS (70 milliarcseconds)

  6. USNO-B1.0 (200 milliarcseconds)

The values listed in the KIC come from the first entry in this list that contains each star. The source catalog should be consulted for a detailed discussion of astrometric accuracy. The quantities listed here are global averages.

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