Access to Astronomical Catalogues

J/AJ/127/1000  Stromgren and Ca photometry of NGC 3680   (Anthony-Twarog+, 2004)
uvbyCaHβ CCD photometry of clusters.
IV. Solving the riddle of NGC 3680.
    Anthony-Twarog B.J., Twarog B.A.
   <Astron. J., 127, 1000-1013 (2004)>
   =2004AJ....127.1000A
ADC_Keywords: Clusters, open ; Photometry, CCD ; Photometry, uvby

Keywords: open clusters and associations: individual (NGC 3680) -
          stars: evolution - techniques: photometric

Abstract:
    CCD photometry on the intermediate-band uvbyCaHβ system is
    presented for the open cluster, NGC 3680. Restricting the data to
    probable cluster members using the color-magnitude diagram (CMD) and
    the photometric indices alone defines a sample of 34 stars at 
    the cluster turnoff that imply E(b-y)=0.042±0.002(s.e.m.) or
    E(B-V)=0.058±0.003(s.e.m.), where the errors refer to internal
    errors alone. With this reddening, [Fe/H] is derived from both m1
    and hk using both b-y and Hβ as the temperature indices.

Description:
    The Caby system was initially defined and developed using traditional
    photoelectric photometry obtained at a number of observatories, but
    predominantly Cerro Tololo Inter-American Observatory (CTIO) and Kitt
    Peak National Observatory, between 1983 and 1996.
    Included in this sample were eight stars in the field of NGC 3680,
    observed with a pulse-counting system equipped with an S-20
    photomultiplier on the 1.0 and 1.5m telescopes at CTIO between 
    1989 and 1992.
Objects:
    ------------------------------------------------------
       RA   (2000)   DE      Designation(s)
    ------------------------------------------------------
    11 25 42     -43 15.0    NGC 3680 = Cl Melotte 106
    ------------------------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table2.dat       119      466   uvbyCaHβ photometry in NGC 3680


See also:
   J/AJ/119/2282 : Stromgren photometry of IC 4651 (Anthony-Twarog+, 2000)
   J/AJ/125/1383 : Stromgren photometry of NGC 6253 (Anthony-Twarog+, 2003)


Byte-by-byte Description of file: table2.dat

   Bytes Format Units   Label     Explanations

   1-  5  A5    ---     Seq       WEBDA primary identification number (1)
   7- 12  F6.2  pix     Xpos      WEBDA X pixel coordinate
  14- 19  F6.2  pix     Ypos      WEBDA Y pixel coordinate
  21- 26  F6.3  mag     Vmag      The V-band magnitude
  28- 32  F5.3  mag     b-y       The Stroemgren (b-y) color
  34- 39  F6.3  mag     m1        ? The Stroemgren m1 index magnitude
      41  A1    ---     n_m1      [g] calibration of m1 (2)
  43- 48  F6.3  mag     c1        ? The Stroemgren C1 index magnitude
      50  A1    ---     n_c1      [g] calibration of c1 (2)
  52- 56  F5.3  mag     beta      ? The Hβ index magnitude
  58- 62  F5.3  mag     hk        ? The hk index [(Ca-b) - (b-y)]
  64- 68  F5.3  mag     e_Vmag    Standard error of the mean in Vmag
  70- 74  F5.3  mag     e_b-y     Standard error of the mean in b-y
  76- 80  F5.3  mag     e_m1      ? Standard error of the mean in m1
  82- 86  F5.3  mag     e_c1      ? Standard error of the mean in c1
  88- 92  F5.3  mag     e_beta    ? Standard error of the mean in beta
  94- 98  F5.3  mag     e_hk      ? Standard error of the mean in hk
 100-101  I2    ---     Ny        Number of y-band frames
 103-104  I2    ---     Nb        Number of b-band frames
 106-107  I2    ---     Nv        Number of v-band frames
 109-110  I2    ---     Nu        Number of u-band frames
 112-113  I2    ---     Nw        Number of w-band frames
 115-116  I2    ---     Nn        Number of n-band frames
 118-119  I2    ---     NCa       Number of Ca-band frames

Note (1): Number as in the WEDBA database, at
           http://obswww.unige.ch/webda/cgi-bin/cross.cgi?ngc3680
Note (2): g indicates index was transformed using the giant calibration.



History:
    From electronic version of the journal

References:
  Anthony-Twarog & Twarog, Paper I   2000AJ....119.2282A, Cat. J/AJ/119/2282
  Anthony-Twarog & Twarog, Paper II  2000AJ....120.3111A
  Twarog et al.,           Paper III 2003AJ....125.1383T, Cat. J/AJ/125/1383
(End)                  Greg Schwarz [AAS], Patricia Vannier [CDS]    02-Jul-2004