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J/A+AS/121/369      UBVRI observations of active stars         (Cutispoto, 1997)
Long-term monitoring of active stars.
VI. UBV(RI)c observations collected in Sep-Oct 1990
    Cutispoto G.
   <Astron. Astrophys. Suppl. Ser. 121, 369 (1997)>
   =1997A&AS..121..369C      (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Photometry, UBVRI ; Photometry, Cousins

Keywords: stars: activity - stars: late-type - stars: variables -
          techniques: photometric

Abstract:
    In the framework of an extensive program focusing on the global
    properties and evolution of active stars, high-precision UBV(RI)c
    photometry of 9 selected stars, collected at the European Southern
    Observatory over the intervals 7-17 September and
    30 September - 10 October 1990, is presented. Significant evolution of
    the light curves, period variations and evidence for long-term
    variability of the global degree of spottedness are found. Some of the
    spectral classifications are discussed. These observations contribute
    to the establishment of a time-extended photometric database which can
    give important clues on topics such as the stability of the spotted
    areas, differential rotation, solar-like cycles and the correlation
    between inhomogeneities at different atmospheric levels.
    For a description of the UBV and (RI)c photometric systems, see e.g.
    General Catalog of Photometric Data GCPD/01 and GCPD/54
Objects:
    ------------------------------------------------
         RA   (2000)   DE      Designation(s)
    ------------------------------------------------
     00 53 04.8   -74 39 07    CF   Tuc = HD   5303
     01 22 19.0   -56 43 52    BC   Phe = HD   8435
     02 34 22.2   -43 47 33    CC   Eri = HD  16157
     04 58 18.2   -75 16 36    YY   Men = HD  32918
     17 17 25.6   -66 56 56    V824 Ara = HD 155555
     18 53 05.6   -50 10 45    PZ   Tel = HD 174429
     20 45 08.3   -31 20 09    AU   Mic = HD 197481
     22 38 43.9   -20 37 12    FK   Aqr = HD 214479
     23 00 27.6   -33 44 34    TZ   PsA = HD 217344
    ------------------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table3.dat        63        9   Maximum luminosity and corresponding colors
                                  for the program stars
table4.dat        36       18   V magnitude and colors for the c and ck stars
                                  derived via standard stars
table.dat         57      108   UBVRI photometry of program stars
tables.tex        80       62   LaTeX version of tables 3 and 4


See also:
    J/A+AS/119/281 : UBV(RI)c photometry of active stars. V. (Cutispoto, 1996)
    J/A+AS/127/207 : UBV(RI)c photometry of active stars. VII. (Cutispoto 1998)
    J/A+AS/131/321 : UBV(RI)c photometry of active stars. VIII. (Cutispoto 1998)
    J/A+A/367/910  : UBV(RI)c photometry of active stars. IX. (Cutispoto+, 2001)
    J/A+A/400/659  : UBV(RI)c photometry of active stars. X (Cutispoto+, 2003)


Table 1: Comparison (c) and check (ck) stars used for each program star
   -------------------------------------------------
     Program Star     Comparison star    Check star
            (v)             (c)            (ck)
   -------------------------------------------------
   HD 5303   = CF Tuc     HD 5210        HD 6446
   HD 8435   = BC Phe     HD 8617        HD 9896
   HD 16157  = CC Eri     HD 16371       SAO 215945
   HD 32918  = YY Men     HD 33763       HD 33747
   HD 155555 = V824 Ara   HD 156427      HD 154775
   HD 174429 = PZ Tel     HD 173560      HD 176557
   HD 197481 = AU Mic     HD 197237      HD 197339
   HD 214479 = FK   Aqr   HD 214046      HD 214380
   HD 217344 = TZ PsA     HD 217108      HD 217935
   -------------------------------------------------

Table2: Mean atmospheric extinction coefficients for La Silla site,
        obtained over the period 7 Sep - 10 Oct 1990
   -------------------------------------------------
                 U    B    V    R    I
   -------------------------------------------------
   Mag/airmass .460 .217 .125 .087 .041
   -------------------------------------------------

Byte-by-byte Description of file: table3.dat

   Bytes Format Units   Label     Explanations

   1-  9  A9    ---     Name      Variable Name (v)
  11- 14  F4.2  mag     Vmax      V-band maximum luminosity
  16- 19  F4.2  mag     U-B       U-B color index at maximum luminosity
  21- 24  F4.2  mag     B-V       B-V color index at maximum luminosity
  26- 29  F4.2  mag     V-Rc      V-Rc color index at maximum luminosity
  31- 34  F4.2  mag     V-Ic      V-Ic color index at maximum luminosity
  36- 37  I2    mmag    Vv-c      Standard deviation for the v-c V-band
                                   differential magnitudes
  39- 40  I2    mmag    Vck-c     Standard deviation for the ck-c V-band
                                   differential magnitudes
  42- 43  I2    ---     o_Vmax    Number of nights
  46- 63  A18   ---     Sp        Inferred spectral type


Byte-by-byte Description of file: table4.dat

   Bytes Format Units   Label     Explanations

   1- 10  A10   ---     HD        c or ck HD number
  12- 15  F4.2  mag     Vmag      V-band magnitude
  17- 20  F4.2  mag     U-B       U-B color  index
      21  A1    ---     u_U-B     Uncertainty flag on U-B (1)
  23- 26  F4.2  mag     B-V       B-V color  index
  28- 31  F4.2  mag     V-Rc      V-Rc color index
  33- 36  F4.2  mag     V-Ic      V-Ic color index

Note (1): Errors are of the order of 0.01 magnitudes.
          The symbol ":" denotes errors of the order of 0.02 magnitudes


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

   Bytes Format Units   Label     Explanations

   1-  8  A8    ---     Name      Star name
  10- 21  F12.4 d       HJD       Heliocentric Julian day
  23- 27  F5.4  ---     Phase     [0/1[ Phase (1)
  29- 33  F5.3  mag     Vmag      V magnitude
  35- 39  F5.3  mag     U-B       ? U-B color index
  41- 45  F5.3  mag     B-V       B-V color index
  47- 51  F5.3  mag     V-R       V-R color index
  53- 57  F5.3  mag     V-I       V-I color index

Note (1): Phases are computed using the ephemeride:
      CF   Tuc  : HJD=2444554.992 + 2.797672 x E
      BC   Phe  : HJD=2447869.0   + 0.649 x E
      CC   Eri  : HJD=2447129.529 + 1.56145 x E
      YY   Men  : HJD=2444155.64  + 9.5476 x E
      V824 Ara  : HJD=2445803.07  + 1.681652 x E
      PZ   Tel  : HJD=2448141.5   + 0.9447 x E
      AU   Mic  : HJD=2441054.0   + 4.865 x E
      FK   Aqr  : HJD=2448141.0   + 4.252 x E
      TZ   PsA  : HJD=2448141.54  + 1.648 x E


Acknowledgements: Giuseppe Cutispoto 


References:
     Rodono & Cutispoto, Paper I      1992A&AS...95...55R
     Cutispoto           Paper II     1992A&AS...95..397C
     Cutispoto           Paper III    1993A&AS..102..655C
     Cutispoto           Paper IV     1995A&AS..111..507C
     Cutispoto           Paper V      1996A&AS..119..281C, Cat. J/A+AS/119/281
     Cutispoto           Paper VII    1998A&AS..127..207C, Cat. J/A+AS/127/207
     Cutispoto           Paper VIII   1998A&AS..131..321C, Cat. J/A+AS/131/321
     Cutispoto et al.,   Paper IX     2001A&A...367..910C, Cat. J/A+A/367/910
     Cutispoto et al.,   Paper X      2003A&A...400..659C, Cat. J/A+A/400/659
(End) Patricia Bauer  [CDS]   24-Jul-1996