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 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 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:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 77 34 Star positions and magnitudes (from Simbad)
tablea1.dat 113 161 Orbital elements
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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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
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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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
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Acknowledgements: Jens Woitas
(End) Patricia Bauer [CDS] 16-Feb-2001