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J/A+A/333/619     Upper Scorpius OB association Lithium survey (Preibisch+ 1998)
A lithium-survey for pre-main sequence stars in the upper
Scorpius OB association
       Preibisch T., Guenther E., Zinnecker H., Sterzik M., Frink S., Roeser S.
      <Astron. Astrophys. 333, 619 (1998)>
      =1998A&A...333..619P      (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Equivalent widths ; Proper motions ;
              Associations, stellar
Keywords: surveys - stars: kinematics - stars: pre-main sequence -
          open clusters and associations: Scorpius Centaurus - X-rays: stars

Abstract:
    We present the results of an intermediate resolution spectroscopic
    survey for pre-main sequence (PMS) stars in the Upper Scorpius OB
    association. In a 160 square-degree area we were able to identify 39
    new PMS stars by follow up observations of X-ray selected stars with
    the multi object spectrograph FLAIR at the UK Schmidt Telescope. We
    also investigated the completeness of our X-ray selected sample by
    observing more than 100 stars that were not detected as X-ray sources,
    but have proper motions indicating membership to Upper Sco. While the
    new X-ray selected PMS stars with known proper motions have kinematics
    consistent with membership, none of the X-ray quiet proper motion
    candidates is a PMS star. We conclude that our X-ray selected sample
    of PMS stars seems to be rather complete. For stars in the magnitude
    interval 11.5≲B≲13.5 we derive a conservative lower limit of 75%
    completeness.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
tablea1.dat       79       78   Results for the X-ray selected PMS candidates
tablea2.dat       72      115   Results for the proper motion selected PMS candidates


Byte-by-byte Description of file: tablea1.dat

   Bytes Format Units   Label    Explanations

   1-  9  A9    ---     GSC      GSC (Cat. I/220) number
      11  A1    ---     Index    See Note (1)
  13- 14  I2    h       RAh      Right ascension (J2000)
  16- 17  I2    min     RAm      Right ascension (J2000)
  19- 22  F4.1  s       RAs      Right ascension (J2000)
      25  A1    ---     DE-      Declination sign
  26- 27  I2    deg     DEd      Declination (J2000)
  29- 30  I2    arcmin  DEm      Declination (J2000)
  32- 33  I2    arcsec  DEs      Declination (J2000)
  36- 39  F4.1  mag     Bmag     B magnitude from GSC (Cat. I/220)
  42- 46  F5.3  ct/s    CR       ROSAT count rate
      49  A1    ---     u_CR     [:<] Uncertainty/upper limit note (2)
  50- 53  F4.2  0.1nm   W(Li)    Li line equivalent width
      54  A1    ---     u_W(Li)  [:<] Uncertainty/upper limit note (2)
  56- 61  F6.2  0.1nm   W(Ha)    Hα line equivalent width
  63- 64  A2    ---     SpType   Spectral type
      65  A1    ---    u_SpType  Uncertainty flag on SpType
  67- 69  A3    ---     Type     See Note (3)
  71- 74  I4    mas/yr  pmRA     ? Proper motion in right ascension *cos(delta)
  76- 78  I3    mas/yr  pmDE     ? Proper motion in declination

Note (1): empty: X-ray source detected in the ROSAT All Sky Survey
              P: X-ray source detected in pointed ROSAT observation only
Note (2): "<": Upper limit to the line width
          ":": Uncertainty exceeding 15%
Note (3): Classification of the objects
           PMS: pre-main sequence star
            YC: non-PMS star with a Lithium line as typical for stars in the
                 young clusters mentioned in Section 4
             F: non-PMS star with a very weak lithium line
                 (probably active field star)


Byte-by-byte Description of file: tablea2.dat

   Bytes Format Units   Label     Explanations

   1-  9  A9    ---     GSC       GSC (Cat. I/220) number
  12- 13  I2    h       RAh       Right ascension (J2000)
  15- 16  I2    min     RAm       Right ascension (J2000)
  18- 21  F4.1  s       RAs       Right ascension (J2000)
      24  A1    ---     DE-       Declination sign
  25- 26  I2    deg     DEd       Declination (J2000)
  28- 29  I2    arcmin  DEm       Declination (J2000)
  31- 32  I2    arcsec  DEs       Declination (J2000)
  36- 39  F4.1  mag     Bmag      B magnitude from GSC
      42  A1    ---     u_Bmag    [:<] Uncertainty/upper limit note (1)
  43- 46  F4.2  0.1nm   W(Li)     Li line equivalent width
      47  A1    ---     u_W(Li)   [:<] Uncertainty/upper limit note (1)
  50- 53  F4.2  0.1nm   W(Ha)     Hα line equivalent width
  56- 57  A2    ---     SpType    Spectral type
      58  A1    ---     u_SpType  Uncertainty flag on SpType
  60- 61  A2    ---     Type      See Note (2)
  64- 66  I3    mas/yr  pmRA      Proper motion in right ascension *cos(delta)
  69- 71  I3    mas/yr  pmDE      Proper motion in declination

Note (1): <": Upper limit to the line width
         ":": Uncertainty exceeding 15%
Note (2): Classification of the objects
           YC: non-PMS star with a Lithium line as typical for stars in the
               young clusters mentioned in Section 4
            F: non-PMS star with a very weak lithium line
               (probably active field star)


Acknowledgements: Thomas Preibisch 

(End)                                         Patricia Bauer [CDS]   13-Feb-1998