The young, tight and low mass binary TWA22AB: a new calibrator for evolutionary models ? Orbit, spectral types and temperatures
DUCOURANT, C.
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
Observatoire aquitain des sciences de l'univers [OASU]
< Réduire
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
Observatoire aquitain des sciences de l'univers [OASU]
Langue
en
Article de revue
Ce document a été publié dans
Astronomy and Astrophysics - A&A. 2009, vol. 506, n° 2, p. 799-810
EDP Sciences
Résumé en anglais
Tight binaries discovered in young, nearby associations, with known distances, are ideal targets to provide dynamical mass measurements to test the physics of evolutionary models at young ages and very low masses. We report ...Lire la suite >
Tight binaries discovered in young, nearby associations, with known distances, are ideal targets to provide dynamical mass measurements to test the physics of evolutionary models at young ages and very low masses. We report for the first time the binarity of TWA22, possible new dynamical calibrator for evolutionary models at young ages. Based on an accurate trigonometric distance (17.53 +- 0.21 pc) determination, we infer a total dynamical mass of 220 +- 21 MJup for the system. From the resolved near-infrared integral-field spectroscopy, we find an effective temperature Teff=2900+200-200 K for TWA22 A and Teff=2900+200-100 K for TWA22 B and surface gravities between 4.0 and 5.5 dex. From our photometry and a M6 +- 1 spectral type for both components, we find luminosities of log(L/Lsun)=-2.11 +- 0.13 dex and log(L/Lsun)=-2.30 +- 0.16 dex for TWA22 A and B respectively. By comparing these parameters with evolutionary models, we question the age and the multiplicity of this system. We also discuss a possible underestimation of the mass predicted by evolutionary models for young stars close to the substellar boundary.< Réduire
Mots clés en anglais
formation
Instrumentation: adaptive optics
Stars: fundamental parameters
low-mass
brown dwarfs
binary (TWA22 AB): close
spectrographs
stars
Origine
Importé de halUnités de recherche