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J/AJ/127/1588       47 Tuc main-sequence star abundances     (Briley+, 2004)
On the carbon and nitrogen abundances of 47 Tucanae's main-sequence stars.
    Briley M.M., Harbeck D., Smith G.H., Grebel E.K.
   <Astron. J., 127, 1588-1593 (2004)>
   =2004AJ....127.1588B
ADC_Keywords: Clusters, globular ; Stars, dwarfs ; Abundances

Keywords: globular clusters: general -
          globular clusters: individual (47 Tucanae) - stars: evolution -
          stars: abundances

Abstract:
    We report the results of an analysis of CN and CH band strengths among
    a large sample of 47 Tucanae main-sequence and turnoff stars presented
    earlier by Harbeck et al. (2003, Cat. J/AJ/125/197).

Description:
    The sample selection, observations, and reduction of the 47 Tuc MS and
    MSTO spectra used in this analysis are described in Harbeck et al.
    (2003, Cat. J/AJ/125/197). To summarize, 115 program stars were
    selected from MPG/ESO 2.2m images of 47 Tuc to span a range in
    luminosity from the MSTO to 2.5mag fainter. Photometry of the stars
    was also extracted from these images. The spectra were obtained at the
    ESO Very Large Telescope.
Objects:
    ----------------------------------------------------------
       RA   (2000)   DE      Designation(s)
    ----------------------------------------------------------
    00 24 05.2   -72 04 58   47 Tuc = NGC 104
    ----------------------------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat        74      109   Observed Indices, Model Parameters, and
                             Resulting Abundances


See also:
   J/AJ/125/197 : CN abundances of the 47 Tuc main sequence (Harbeck+, 2003)


Byte-by-byte Description of file: table1.dat

   Bytes Format Units     Label     Explanations

   1-  4  I4    ---       HSG       Identification number, Cl* NGC 104 HSG NNNN
   6- 11  F6.3  mag       Vmag      Johnson V band magnitude (1)
  13- 17  F5.3  mag       B-V       Johnson (B-V) color index (1)
  19- 24  F6.3  ---       S3839     CN (S(3839)) index
  26- 30  F5.3  ---       I(CH)     CH (I(CH)) index
  32- 37  F6.3  ---       MgH       ? The MgH index (2)
      39  A1    ---       Memb      [YN?] Cluster membership (3)
  41- 44  I4    K         Teff      ? Effective temperature
  46- 49  F4.2  [cm/s2]   log(g)    ? Log of the surface gravity
  51- 55  F5.2  [---]     [C/Fe]    ? Log of the carbon to iron abundance
  57- 60  F4.2  [---]     [N/Fe]    ? Log of the nitrogen to iron abundance
  62- 67  F6.3  ---       MS3839    ? Model value for S3839
  69- 73  F5.3  ---       MI(CH)    ? Model value for I(CH)

Note (1): Note that the V, B-V values of Harbeck et al. (2003, J/AJ/125/197)
     include an extinction correction of 0.128 and 0.04 (respectively).
     The values listed here are uncorrected.
Note (2): Nine spectra did not extend redward enough for the MgH index to
     be measured. They are assumed to be members based on the criteria of
     Harbeck (2003, J/AJ/125/197) and included in the subsequent analysis. 
     No modeling was done for the presumed non-members.
Note (3): Membership flags:
      Y = cluster member;
      N = not a cluster member;
      ? = no MgH index available (see Note 2).


History:
    From electronic version of the journal
(End)                  Greg Schwarz [AAS], Patricia Vannier [CDS]    17-May-2004