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Spectroscopic binaries in the Solar Twin Planet Search program: from substellar-mass to M dwarf companions

By SpaceRef Editor
August 30, 2017
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Leonardo A. dos Santos, Jorge Meléndez, Megan Bedell, Jacob L. Bean, Lorenzo Spina, Alan Alves-Brito, Stefan Dreizler, Iván Ramírez, Martin Asplund
(Submitted on 24 Aug 2017)

Previous studies on the rotation of Sun-like stars revealed that the rotational rates of young stars converge towards a well-defined evolution that follows a power-law decay. It seems, however, that some binary stars do not obey this relation, often by displaying enhanced rotational rates and activity. In the Solar Twin Planet Search program we observed several solar twin binaries, and found a multiplicity fraction of 42%±6% in the whole sample; moreover, at least three of these binaries (HIP 19911, HIP 67620 and HIP 103983) clearly exhibit the aforementioned anomalies. We investigated the configuration of the binaries in the program, and discovered new companions for HIP 6407, HIP 54582, HIP 62039 and HIP 30037, of which the latter is orbited by a 0.06 M⊙ brown dwarf in a 1-month long orbit. We report the orbital parameters of the systems with well-sampled orbits and, in addition, the lower limits of parameters for the companions that only display a curvature in their radial velocities. For the linear trend binaries, we report an estimate of the masses of their companions when their observed separation is available, and a minimum mass otherwise. We conclude that solar twin binaries with low-mass stellar companions at moderate orbital periods do not display signs of a distinct rotational evolution when compared to single stars. We confirm that the three peculiar stars are double-lined binaries, and that their companions are polluting their spectra, which explains the observed anomalies.

Comments:    13 pages, 7 figures, accepted for publication in MNRAS
Subjects:    Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
DOI:    10.1093/mnras/stx2199
Cite as:    arXiv:1708.07465 [astro-ph.SR] (or arXiv:1708.07465v1 [astro-ph.SR] for this version)
Submission history
From: Leonardo A. dos Santos
[v1] Thu, 24 Aug 2017 15:46:14 GMT (280kb,D)

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