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J/A+A/369/249       T Tauri binary systems orbital motion    (Woitas+, 2001)

Orbital motion in T Tauri binary systems Woitas J., Koehler R., Leinert C. <Astron. Astrophys. 369, 249 (2001)> =2001A&A...369..249W
ADC_Keywords: Binaries, orbits ; Stars, pre-main sequence ; Stars, variable Keywords: stars: binaries: visual - stars: pre-main sequence - techniques: interferometric Abstract: Using speckle-interferometry we have carried out repeated measurements of relative positions for the components of 34 T Tauri binary systems. The projected separation of these components is low enough that orbital motion is expected to be observable within a few years. In most cases orbital motion has indeed been detected. The observational data is discussed in a manner similar to Ghez et al. (1995AJ....110..753G). However, we extend their study to a larger number of objects and a much longer timespan. The database presented in this paper is valuable for future visual orbit determinations. It will yield empirical masses for T Tauri stars that now are only poorly known. The available data is however not sufficient to do this at the present time. Instead, we use short series of orbital data and statistical distributions of orbital parameters to derive an average system mass that is independent of theoretical assumptions about the physics of PMS stars. For our sample this mass is and thus in the order of magnitude one expects for the mass sum of two T Tauri stars. It is also comparable to mass estimates obtained for the same systems using theoretical PMS evolutionary models. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file stars.dat 90 34 Star positions and magnitudes (from Simbad) tablea1.dat 114 161 Orbital elements
Byte-by-byte Description of file: stars.dat
Bytes Format Units Label Explanations
1- 16 A16 --- Name Object name 19- 34 A16 --- SName Simbad designation 36- 37 I2 h RAh Right ascension (J2000.0) 39- 40 I2 min RAm Right ascension (J2000.0) 42- 45 F4.1 s RAs Right ascension (J2000.0) 47 A1 --- DE- Declination sign (J2000.0) 48- 49 I2 deg DEd Declination (J2000.0) 51- 52 I2 arcmin DEm Declination (J2000.0) 54- 55 I2 arcsec DEs ? Declination (J2000.0) 59- 63 F5.2 mag Bmag ? B magnitude 65- 69 F5.2 mag Vmag ? V magnitude 71- 90 A20 --- SpType Spectral type
Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 16 A16 --- Name Object name 18- 19 I2 d OBS.D Date of observation (day) 21- 23 A3 --- OBS.M Date of observation (month) 25- 28 I4 yr OBS.Y Date of observation (year) 30- 40 A11 --- Filt Filter(s) 43- 47 F5.3 --- I2/I1 ? Flux ratio of the 2 components 49- 53 F5.3 --- e_I2/I1 ? Error of flux ratio 55- 59 F5.1 deg PA ? Position angle 61- 64 F4.1 deg e_PA ? Error of position angle 66- 70 F5.1 mas rho ? Separation 72- 73 I2 mas e_rho ? Error of separation 75- 93 A19 --- Ref Bibcode of the reference 95-114 A20 --- n_Ref Author's name for the references
Acknowledgements: Jens Woitas
(End) Patricia Bauer [CDS] 16-Feb-2001
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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