J/A+A/461/183 Variability of classical T Tauri (Grankin+, 2007)
Results of the ROTOR-program.
I. The long-term photometric variability of classical T Tauri stars.
Grankin K.N., Melnikov S.Y., Bouvier J., Herbst W., Shevchenko V.S.
<Astron. Astrophys. 461, 183 (2007)>
=2007A&A...461..183G 2007A&A...461..183G
ADC_Keywords: Stars, pre-main sequence ; Photometry, UBVRI
Keywords: stars: activity - stars: pre-main sequence - stars: variables: general
Abstract:
We report the results of a study the long term variability of
Classical T Tauri stars (CTTS) over up to 20 years, characterize it
from a set of statistical parameters and discuss its origin. We
characterize the long term photometric variations of 49 CTTs with
sufficient data for allowing a robust statistical analysis and propose
an empirical classification scheme. Several patterns of long term
photometric variability are identified. The most common pattern,
exhibited by a group of 15 stars which includes T Tau itself, consists
of low level variability (with V-amplitude less than 0.4mag) with no
significant changes occurring from season to season over many years. A
related subgroup of 22 stars exhibit a similar stable long term
variability pattern, though with larger amplitudes (up to 1.6mag).
Besides these representative groups, we identify three smaller groups
of 3-5 stars each of which have distinctive photometric properties.
The long term variability of most CTTS is fairly stable and merely
reflects shorter term variability due to cold and hot surface spots.
Only a small fraction of CTTS undergo significant brightness changes
on the long term (months, years), which probably arise from slowly
varying circumstellar extinction.
Description:
The photometric observations of CTTS were carried out over a period
extending from 1983 up to 2003. The database contains more than 21000
UBVR-observations of 72 CTTs. All the data were collected within the
framework of the ROTOR-program at Mount Maidanak Observatory
(Uzbekistan).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 79 72 List of the stars
phot/* . 72 Individual photometry
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See also:
J/A+A/299/89 : COYOTES II (Bouvier+, 1995)
J/A+A/310/143 : Variability of classical T Tauri stars (Fernandez+, 1996)
J/A+AS/120/267 : T Tauri stars UBrHalphaz photometry (Osterloh+ 1996)
J/A+AS/128/561 : UBVRI photometry of southern T Tauri stars (Batalha+ 1998)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Simbad name
17- 18 I2 h RAh Simbad Hour of Right Ascension (J2000.0)
20- 21 I2 min RAm Simbad Minute of Right Ascension (J2000.0)
23- 26 F4.1 s RAs Simbad Second of Right Ascension (J2000.0)
28 A1 --- DE- Simbad Sign of the Declination (J2000.0)
29- 30 I2 deg DEd Simbad Degree of Declination (J2000.0)
32- 33 I2 arcmin DEm Simbad Arcminute of Declination (J2000.0)
35- 36 I2 arcsec DEs Simbad Arcsecond of Declination (J2000.0)
40- 44 F5.2 mag Bmag ? Simbad B band magnitude
46- 50 F5.2 mag Vmag ? Simbad V band magnitude
52- 62 A11 --- SpType Simbad MK spectral type
67- 79 A13 --- FileName Data file name, in "phot" subdirectory
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Byte-by-byte Description of file: phot/*
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian date
14- 19 F6.3 mag Vmag ?=9.999 Johnson V magnitude
21- 26 F6.3 mag U-B ?=9.999 Johnson (U-B) color index
28- 33 F6.3 mag B-V ?=9.999 Johnson (B-V) color index
35- 40 F6.3 mag V-R ?=9.999 Johnson (V-R) color index
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Acknowledgements:
Jerome bouvier, Jerome.Bouvier(at)obs.ujf-grenoble.fr
(End) Patricia Vannier [CDS] 02-Nov-2006