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 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 AV=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 Hα 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:
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RA (2000) DE Designation(s)
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04 21 57.3 +28 26 37 RY Tau = HD 283571
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File Summary:
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FileName Lrecl Records Explanations
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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
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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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
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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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
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Note (1): correction for interstellar polarization: P(max)=2.84%, PA=26 deg.
(lambda(max)=5500Å) (see text)
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Acknowledgements: Rolf Duemmler
(End) [CDS] 28-Oct-1998