ADC/CDS Standard Document for Catalog:
/journal_tables/A+A/310/143/

1. Use the ADC Data Viewer Suite to visualize the data.
2. Get the data files via anonymous FTP. (See Note.)

J/A+A/310/143       Variability of classical T Tauri stars (Fernandez+, 1996)
================================================================================
Variability of classical T Tauri stars. Its relation to the accretion process
       Fernandez M., Eiroa C.
      <Astron. Astrophys. 310, 143 (1996)>
      =1996A&A...310..143F      (SIMBAD/NED BibCode)
================================================================================
ADC_Keywords: Photometry, UBVRI
Keywords: stars: formation - stars: pre-main sequence - accretion disks
          stars spots

Description:
    We present the analysis of a UBV(RI)c photometric monitoring program
    carried out from July 1988 to August 1992 on a sample of 13 classical
    T Tauri stars and 2 suspected classical T Tauri stars. We detected
    optical irregular variability with an amplitude larger than 0.1mag in
    the V band in 8 stars. For 5 of them most of the variability can be
    attributed to hot spots, for one, to cool spots and for two of them,
    there is no clear mechanism; nevertheless, other phenomena must
    explain the short term (hours - days) and long term (years)
    variations superimposed. For some objects an anomalous behaviour at
    the shorter wavelengths (U band) is detected. From the comparison
    between the amplitude of the optical variability due to hot spots and
    the equivalent width of the Halpha emission a correlation between them
    is suggested. Assuming that the Halpha emission is related to the
    accretion process, this correlation supports the idea that we are
    observing the hot spots where the material from the accretion disks
    falls onto the star.
    For a description of the (RI)c photometric system, see e.g.
    <GCPD/54>

File Summary:
--------------------------------------------------------------------------------
  FileName      Lrecl  Records   Explanations
--------------------------------------------------------------------------------
ReadMe             80        .   This file
tables             79       35   Average values of the photometric observations
--------------------------------------------------------------------------------

Byte-by-byte Description of files: tables
--------------------------------------------------------------------------------
   Bytes Format  Units     Label   Explanations
--------------------------------------------------------------------------------
   1- 14  A14    ---       Name    Star name
  17- 28  A12    ---       Date    Observing run (1)
  33- 37  F5.2   mag       Vmag    V band
  45- 48  F4.2   mag       B-V     (B-V) colour index
  56- 59  F4.2   mag       U-B     []? (U-B) colour index
  66- 69  F4.2   mag       V-R     []? (V-R) colour index
  76- 79  F4.2   mag       V-I     []? (V-I) colour index
--------------------------------------------------------------------------------
Note (1): R and J denote the Romeo and Juliet photometers at the JKT telescope,
           respectively.
--------------------------------------------------------------------------------

Courtesy: M. Fernandez <matilde@astroscu.unam.mx>
================================================================================
(End)                                           Patricia Bauer [CDS] 08-Feb-1996