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J/MNRAS/358/13      Faint dwarfs in NGC 2547                (Jeffries+, 2005)
The Lithium depletion boundary in NGC 2547 as a test of pre-main-sequence
evolutionary models.
    Jeffries R.D., Oliveira J.M.
   <Mon. Not. R. Astron. Soc., 358, 13-29 (2005)>
   =2005MNRAS.358...13J
ADC_Keywords: Clusters, open ; Stars, dwarfs ; Radial velocities ;
              Abundances
Keywords: stars: abundances - stars: late-type -
          open clusters and associations: individual: NGC 2547

Abstract:
    Intermediate resolution spectroscopy from the European Southern
    Observatory Very Large Telescope is analysed for 63 photometrically
    selected low-mass (0.08-0.30M☉) candidates of the open cluster
    NGC 2547. We have confirmed membership for most of these stars using
    radial velocities, and found that lithium remains undepleted for
    cluster stars with I>17.54±0.14 and Ks>14.86±0.12. From these
    results, several pre-main-sequence evolutionary models give almost
    model independent ages of 34-36Myr, with a precision of 10%.
    These ages are only slightly larger than the ages of 25-35(±5)Myr
    obtained using the same models to fit isochrones to higher mass stars
    descending towards the zero-age main-sequence, both in empirically
    calibrated and theoretical colour-magnitude diagrams. This agreement
    between age determinations in different mass ranges is an excellent
    test of the current generation of low-mass pre-main-sequence stellar
    models and lends confidence to ages determined with either method
    between 30 and 120Myr.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat       114       63   Targets observed


See also:
    J/MNRAS/335/291  : BVI photometry of NGC 2547 (Naylor+, 2002)
    J/MNRAS/351/1401 : RcIcZ photometry of NGC 2547 (Jeffries+, 2004)


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

   Bytes Format Units   Label   Explanations

   1-  2  I2    ---     JO      Identifier used in this paper,
                                 Cl* NGC 2547 JO NN in Simbad
   4-  5  A2    ---     Field   Field designation, from Jeffries et al., 2004,
                                 Cat. J/MNRAS/351/1401
   7- 10  I4    ---     ID1     Star designation from Jeffries et al., 2004,
                                 Cat. J/MNRAS/351/1401
                                 (Cl* NGC 2547 JND FF-NNNN in Simbad)
      11  A1    ---     n_ID1   [N] if source was not considered a photometric
                                    member in J/MNRAS/351/1401
  13- 14  I2    h       RAh     Right Ascension J2000 (hours)
  16- 17  I2    min     RAm     Right Ascension J2000 (minutes)
  19- 24  F6.3  s       RAs     Right Ascension J2000 (seconds)
      26  A1    ---     DE-     Declination J2000 (sign)
  27- 28  I2    deg     DEd     Declination J2000 (degrees)
  30- 31  I2    arcmin  DEm     Declination J2000 (minutes)
  33- 37  F5.2  arcsec  DEs     Declination J2000 (seconds)
  39- 44  F6.3  mag     Icmag   Cousins I magnitude from J/MNRAS/351/1401
  46- 50  F5.3  mag     Rc-Ic   Rc-Ic colour index from J/MNRAS/351/1401
  52- 56  F5.3  mag     Ic-Z    Ic-Z colour index from J/MNRAS/351/1401
  58- 63  F6.3  mag     Jmag    ? J magnitude from 2MASS II/246
  65- 70  F6.3  mag     Hmag    ? H magnitude from 2MASS II/246
  72- 77  F6.3  mag     Ksmag   ? Ks magnitude from 2MASS II/246
  79- 82  A4    ---     SpType  Estimated MK spectral type
  84- 88  F5.1  km/s    RV1     Relative radial velocity on night 1
      89  A1    ---     n_RV1   [b] indicates broadened lines
  91- 95  F5.1  km/s    RV2     ? Relative radial velocity on night 2
      96  A1    ---     n_RV2   [b] indicates broadened lines
      97  A1    ---     f_RV2   [V] indicates a variable velocity
  99-100  I2    ---     SNR     empirical spectrum signal-to-noise ratio
     102  A1    ---     l_Li    Limit flag (<) on Li
 103-106  F4.2  0.1nm   Li      Equivalent width of the Li 6708Å feature
 108-111  F4.2  0.1nm   e_Li    ? Mean error on Li
     112  A1    ---     n_Li    [b] indicates a broadened Li line
     114  I1    ---     Mem     [1,4] Membership status (1)

Note (1): The status takes the following values:
      1 = RV member with no Li
      2 = RV member with Li
      3 = RV non-member with Li
      4 = RV non-member with no Li


Acknowledgements:
    Thanks to Rob Jeffries for a complete source table, kindly forwarded
    by Brian Skiff.
(End)                                   Francois Ochsenbein [CDS]    07-Sep-2005