UVBYBETA

       Derive dereddened colors, metallicity, and Teff from Stromgren colors.

       Adapted from FORTRAN routine of same name published by T.T. Moon,
       Communications of University of London Observatory, No. 78. Parameters
       can either be input interactively (with /PROMPT keyword) or supplied
       directly.

       uvbybeta, /PROMPT               ;Prompt for all parameters
       uvbybeta,by,m1,c1,Hbeta,n        ;Supply inputs, print outputs
       uvbybeta, by, m1, c1, Hbeta, n, Te, Mv, Eby, delm0, radius,
                       [ TEXTOUT=, Eby_in =, Name =  ]

       by - Stromgren b-y color, scalar or vector
       m1 - Stromgren line-blanketing parameter, scalar or vector
       c1 - Stromgren Balmer discontinuity parameter, scalar or vector
       Hbeta - H-beta line strength index.  Set  Hbeta to 0 if it is not
            known, and UVBYBETA will estimate a value based on by, m1,and c1.
            Hbeta is not used for stars in group 8.
       n -  Integer (1-8), scalar or vector,  giving approximate stellar
            classification
       (1) B0 - A0, classes III - V, 2.59 < Hbeta < 2.88,-0.20 <   c0  < 1.00
       (2) B0 - A0, class   Ia     , 2.52 < Hbeta < 2.59,-0.15 <   c0  < 0.40
       (3) B0 - A0, class   Ib     , 2.56 < Hbeta < 2.61,-0.10 <   c0  < 0.50
       (4) B0 - A0, class   II     , 2.58 < Hbeta < 2.63,-0.10 <   c0  < 0.10
       (5) A0 - A3, classes III - V, 2.87 < Hbeta < 2.93,-0.01 < (b-y)o< 0.06
       (6) A3 - F0, classes III - V, 2.72 < Hbeta < 2.88, 0.05 < (b-y)o< 0.22
       (7) F1 - G2, classes III - V, 2.60 < Hbeta < 2.72, 0.22 < (b-y)o< 0.39
       (8) G2 - M2, classes  IV _ V, 0.20 < m0   < 0.76, 0.39 < (b-y)o< 1.00

       Eby_in - numeric scalar specifying E(b-y) color to use.   If not
             supplied, then E(b-y) will be estimated from the Stromgren colors
       NAME - scalar or vector string giving name(s) of star(s).  Used only
               when writing to  disk for identification purposes.
       /PROMPT - if set, then uvbybeta.pro will prompt for Stromgren indicies
                interactively
       TEXTOUT  -  Used to determine output device.  If not present, the
               value of the !TEXTOUT system variable is used (see TEXTOPEN)
               textout=1       Terminal with /MORE (if a tty)
               textout=2       Terminal without /MORE
               textout=3       uvbybeta.prt   (output file)
               textout=4       Laser Printer
               textout=5       User must open file
               textout=7       Append to existing uvbybeta.prt file
               textout = filename (default extension of .prt)
      /PRINT - if set, then force display output information to the device
               specified by !TEXTOUT.    By default, UVBYBETA does not display
               information if output variables are supplied (and TEXTOUT is
               not set).

       Te - approximate effective temperature
       MV - absolute visible magnitude
       Eby - Color excess E(b-y)
       delm0 - metallicity index, delta m0, (may not be calculable for early
               B stars).
       radius - Stellar radius (R/R(solar))

       Suppose 5 stars have the following Stromgren parameters
       by = [-0.001 ,0.403, 0.244, 0.216, 0.394 ]
       m1 = [0.105, -0.074, -0.053, 0.167, 0.186 ]
       c1 = [0.647, 0.215, 0.051, 0.785, 0.362]
       hbeta = [2.75, 2.552, 2.568, 2.743, 0 ]
       nn = [1,2,3,7,8]              ;Processing group number
       Determine stellar parameters and write to a file uvbybeta.prt
       IDL> uvbybeta, by,m1,c1,hbeta, nn, t=3
            ==> E(b-y) = 0.050    0.414   0.283  0.023  -0.025
                Teff =   13060    14030   18420  7250    5760
                M_V =    -0.27    -6.91   -5.94  2.23    3.94
                radius=  2.71     73.51    39.84 2.02    1.53

       The non-standard system variables !TEXTOUT and !TEXTUNIT will be
       automatically defined if they are not already present.
       DEFSYSV,'!TEXTOUT',1
       DEFSYSV,'!TEXTUNIT',0

       (1) **This procedure underwent a major revision in January 2002
       and the new calling sequence may not be compatible with the old** (NAME
       is now a keyword rather than a parameter.)
       (2) Napiwotzki et al. (1993, A&A, 268, 653) have written a FORTRAN
           program that updates some of the Moon (1985) calibrations.  These
           updates are *not* included in this IDL procedure.

       DEREDD, TEXTOPEN, TEXTCLOSE

       W. Landsman          IDL coding              February, 1988
       Keyword textout added, J. Isensee, July, 1990
       Made some constants floating point.   W. Landsman    April, 1994
       Converted to IDL V5.0   W. Landsman   September 1997
       Added Eby_in, /PROMPT keywords, make NAME a keyword and not a parameter
                 W. Landsman      January 2002

[Home Page] [Software, Documentation] [IDL Documentation] [Quick Reference] [Feedback]