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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 660863.0, MPI für Astronomie / Publikationen_mpia
Orbits and masses in the multiple system LHS 1070
Authors:Köhler, R.; Ratzka, T.; Leinert, C.
Date of Publication (YYYY-MM-DD):2012
Journal Abbrev.:Astronomy and Astrophysics
Start Page:id.A29
Audience:Not Specified
Abstract / Description:<BR /> Aims: We present a study of the orbits of the triple system LHS 1070, with the aim to determine individual masses of its components. <BR /> Methods: Sixteen new relative astrometric positions of the three components in the K band were obtained with NACO at the VLT, Omega CASS at the 3.5 m telescope on Calar Alto, and other high-spatial-resolution instruments. We combined them with data from the literature and fit orbit models to the dataset. We derived an improved fit for the orbit of LHS 1070 B and C around each other, and an estimate for the orbit of B and C around A. <BR /> Results: The orbits are nearly coplanar, with a misalignment angle of less than 10°. The masses of the three components are MA = 0.13...0.16 M&sun;, MB = 0.077 ± 0.005 M&sun;, and MC = 0.071 ± 0.004 M&sun;. Therefore, LHS 1070 C is certainly, and LHS 1070 B probably a brown dwarf. Comparison with theoretical isochrones shows that LHS 1070 A is either fainter or more massive than expected. One possible explanation would be that it is a binary. However, the close companion reported previously could not be confirmed. Based on observations collected at the European Southern Observatory, Chile, proposals number 60.A-9026, 66.C-0219, 67.C-0354, 68.C-0539, 70.C-0476, 072.C-0022, 074.C-0637, 078.C-0386, 380.C-0179, 382.C-0324, and 382.C-0329.
Free Keywords:stars: low-mass; brown dwarfs; stars: fundamental parameters; stars: individual: LHS 1070; binaries: close; celestial mechanics
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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