Improved orbital solution and masses for the very low-mass multiple system LHS 1070*
Universität Göttingen, Institut für Astrophysik, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany e-mail: firstname.lastname@example.org
2 Universität Jena, Astrophysikalisches Institut und Universitäts-Sternwarte, Schillergässchen 2, 07745 Jena, Germany
3 ESO, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
4 ESO, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago 19, Chile
Accepted: 16 February 2008
We present a refined orbital solution for the components A, B, and C of the nearby late-M type multiple system LHS 1070. By combining astrometric datapoints from NACO/VLT, CIAO/SUBARU, and PUEO/CFHT, as well as a radial velocity measurement from the newly commissioned near infrared high-resolution spectrograph CRIRES/VLT, we achieve a very precise orbital solution for the B and C components and a first realistic constraint on the much longer orbit of the A-BC system. Both orbits appear to be co-planar. Masses for the B and C components calculated from the new orbital solution () are in excellent agreement with theoretical models, but do not match empirical mass-luminosity tracks. The preliminary orbit of the A-BC system reveals no mass excess for the A component, giving no indication for a previously proposed fourth (D) component in LHS 1070.
Key words: astrometry / stars: binaries / close, stars: low-mass, brown dwarfs
Based on observations made with ESO Telescopes at the Paranal Observatory under programme ID 60.A-9078(A) and 79.C-0106(A), as well as data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. Based also on observations obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.
© ESO, 2008