Orbits and masses in the multiple system LHS 1070

• Verfasst von: Köhler, Rainer [VerfasserIn]
• Verfasst von: Ratzka, Thorsten [VerfasserIn]
• Verfasst von: Leinert, Christoph [VerfasserIn]
• Titel: Orbits and masses in the multiple system LHS 1070
• Verf.angabe: R. Köhler, T. Ratzka and Ch. Leinert
• E-Jahr: 2012
• Jahr: 24 April 2012
• Umfang: 9 S.
• Fussnoten: Gesehen am 07.11.2018
• Titel Quelle: Enthalten in: Astronomy and astrophysics
• Ort Quelle: Les Ulis : EDP Sciences, 1969
• Jahr Quelle: 2012
• Band/Heft Quelle: 541(2012), Artikel-ID A29, Seite 1-9
• ISSN Quelle: 1432-0746
• DOI: doi:10.1051/0004-6361/201118707
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1582640947

Abstract

We present a study of the orbits of the triple system LHS 1070, with the aim to determine individual masses of its components.<i>Methods.<i/> 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.<i>Results.<i/> The orbits are nearly coplanar, with a misalignment angle of less than 10°. The masses of the three components are <i>M<i/><sub><i>A<i/><sub/> = 0.13<i>...<i/>0.16 <i>M<i/><sub>⊙<sub/>, <i>M<i/><sub><i>B<i/><sub/> = 0.077 ± 0.005 <i>M<i/><sub>⊙<sub/>, and <i>M<i/><sub><i>C<i/><sub/> = 0.071 ± 0.004 <i>M<i/><sub>⊙<sub/>. 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.