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693653.0 [No comment] 28.05.2018 16:41 Released

ID: 693653.0, MPI für Astronomie / Publikationen_mpia
Orbits and masses in the young triple system TWA 5
Authors:Köhler, R.; Ratzka, T.; Petr-Gotzens, M. G.; Correia, S.
Date of Publication (YYYY-MM-DD):2013
Title of Journal:Astronomy and Astrophysics
Start Page:id. A80 (8 pp)
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:<BR /> Aims: We aim to improve the orbital elements and determine the individual masses of the components in the triple system TWA 5. <BR /> Methods: Five new relative astrometric positions in the H band were recorded with the adaptive optics system at the Very Large Telescope (VLT). We combine them with data from the literature and a measurement in the Ks band. We derive an improved fit for the orbit of TWA 5Aa-b around each other. Furthermore, we use the third component, TWA 5B, as an astrometric reference to determine the motion of Aa and Ab around their center of mass and compute their mass ratio. <BR /> Results: We find an orbital period of 6.03 ± 0.01 years and a semi-major axis of 63.7 ± 0.2 mas (3.2 ± 0.1 AU). With the trigonometric distance of 50.1 ± 1.8 pc, this yields a system mass of 0.9 ± 0.1 M, where the error is dominated by the error of the distance. The dynamical mass agrees with the system mass predicted by a number of theoretical models if we assume that TWA5 is at the young end of the age range of the TW Hydrae association. We find a mass ratio of MAb/MAa = 1.3-0.4+0.6 , where the less luminous component Ab is more massive. This result is likely to be a consequence of the large uncertainties due to the limited orbital coverage of the observations. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 079.C-0103, 081.C-0393, 386.C-0205, 087.C-0209, 088.C-0046, 089.C-0167, and 090.C-0184.
Free Keywords:stars: low-mass; brown dwarfs; stars: fundamental; parameters; stars: individual: TWA 5; binaries:; close; celestial mechanics
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-6361 [ID No:1]
URL:http://cdsads.u-strasbg.fr/abs/2013A%26A...558A..8... [ID No:2]