ADC/CDS Standard Document for Catalog:
/journal_tables/A+A/341/553/

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

J/A+A/341/553       RY Tau in 1996                (Petrov+ 1999)
================================================================================
Brightening of the T Tauri star RY Tau in 1996.
Photometry, polarimetry and high resolution spectroscopy
     Petrov P.P., Zajtseva G.V., Efimov Yu.S., Duemmler R., Ilyin I.V.,
     Tuominen I., Shcherbakov V.A.
    <Astron. Astrophys. 341, 553 (1999)>
    =1999A&A...341..553P
================================================================================
ADC_Keywords: Stars, pre-main sequence ; Photometry, UBVRI ; Polarization
Keywords: stars: pre-main sequence - stars: individual: RY Tau -
          cirsumstellar matter

Abstract:
    The T Tauri star RY Tau has increased its brightness from V=10.6mag to
    V=9.6mag in October-November 1996. By February-March 1997, the star
    has faded again to V=10.8mag. High-resolution echelle spectra of RY
    Tau were obtained wit h the SOFIN spectrograph at the Nordic Optical
    Telescope (La Palma, Spain) at lo w and high brightness levels of the
    star. No significant changes in the photosph eric lines, which are
    sensitive to temperature and gravity, were noticed. The spectral type
    of RY Tau is defined as G1-2IV, which in combination with photomet ric
    data implies A_V_=1.0-1.3mag. Polarimetric patrol of RY Tau during the
    fadin g of the star showed an increase of its intrinsic polarization
    from 0.5-1.0% at high brightness to about 2% at low brightness in the
    V, R and I bands. The flux radiated in H{alpha} and the IR Ca II
    emission lines remained about the same, in spite of the one magnitude
    difference in the continuum flux. These results indicate that variable
    obscuration of the star by circumstellar dust clo uds was responsible
    for the brightness change of RY Tau, and that the emission l ine
    source is mostly outside of the obscured region.

Objects:
    ----------------------------------------------------------
       RA   (2000)   DE      Designation(s)
    ----------------------------------------------------------
    04 21 57.3   +28 26 37   RY Tau = HD 283571
    ----------------------------------------------------------

File Summary:
--------------------------------------------------------------------------------
  FileName        Lrecl  Records   Explanations
--------------------------------------------------------------------------------
ReadMe             80        .   This file
table2.dat         33      642   UBV-photometry of RY Tau in 1965-1997
table3.dat         66       45   Observed and intrinsic polarization of
                                  RY Tau in UBVRI
--------------------------------------------------------------------------------

Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
   Bytes Format Units   Label     Explanations
--------------------------------------------------------------------------------
   1- 11  F11.3  d      JD        Julian Date
  14- 19  F6.3  mag     Vmag      V magnitude
  22- 26  F5.3  mag     B-V       ? B-V colour index
  29- 33  F5.3  mag     U-B       ? U-B colour index
--------------------------------------------------------------------------------

Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
   Bytes Format Units   Label     Explanations
--------------------------------------------------------------------------------
   1- 11  F11.3 d       JD        Julian Date
      14  A1    ---     band      [UBVRI] photometric band (U,B,V,R,I)
  17- 21  F5.2  mag     mag       Brightness in that band
  25- 28  F4.2  %       P(obs)    Observed polarization in that band
  30- 33  F4.2  %     e_P(obs)    Mean error of the observed polarization
  35- 39  F5.1  deg     PA(obs)   Observed position angle of polarization in
                                   that band
  41- 43  F3.1  deg   e_PA(obs)   Mean error of observed position angle
  47- 50  F4.2  %       P(intr)   Intrinsic polarization in that band (after
                                   correction for interstellar polarization) (1)
  52- 55  F4.2  %     e_P(intr)   Mean error of intrinsic polarization
  57- 61  F5.1  deg     PA(intr)  Position angle of intrinsic polarization in
                                   that band (after correction for interstellar
                                   polarization)
  63- 66  F4.1  deg   e_PA(intr)  Mean error of position angle of intrinsic
                                   polarization
--------------------------------------------------------------------------------
Note (1): correction for interstellar polarization: P(max)=2.84%, PA=26 deg.
           (lambda(max)=5500{AA}) (see text)
--------------------------------------------------------------------------------

Acknowledgements: Rolf Duemmler <rolf@hiisi.oulu.fi>
================================================================================
(End)                                                        [CDS]   28-Oct-1998