EDP Sciences
Free access
Volume 406, Number 1, July IV 2003
Page(s) 293 - 298
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20030756

A&A 406, 293-298 (2003)
DOI: 10.1051/0004-6361:20030756

Visual orbit for the low-mass binary Gliese 22 AC from speckle interferometry

J. Woitas1, 2, V. S. Tamazian3, J. A. Docobo3 and Ch. Leinert2

1  Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
2  Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
3  Observatorio Astronómico Ramón María Aller, Universidade de Santiago de Compostela, Avenida das Ciencias s/n, 15782 Santiago de Compostela, Spain

(Received 19 March 2003 / Accepted 15 May 2003 )

Based on 14 data points obtained with near-infrared speckle interferometry and covering an almost entire revolution, we present a first visual orbit for the low-mass binary system Gliese 22 AC. The quality of the orbit is largely improved with respect to previous astrometric solutions. The dynamical system mass is $0.592\pm 0.065\,M_{\odot}$, where the largest part of the error is due to the Hipparcos parallax. A comparison of this dynamical mass with mass-luminosity relations on the lower main sequence and theoretical evolutionary models for low-mass objects shows that both probably underestimate the masses of M dwarfs. A mass estimate for the companion Gliese 22 C indicates that this object is a very low-mass star with a mass close to the hydrogen burning mass limit.

Key words: stars: individual: Gliese 22 -- stars: binaries: visual -- stars: low-mass, brown dwarfs -- techniques: high angular resolution

Offprint request: J. Woitas, woitas@tls-tautenburg.de

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© ESO 2003