Search for brown-dwarf companions of stars

Johannes Sahlmann; Damien Segransan; Didier Queloz; Stephane Udry; Nuno C. Santos; Maxime Marmier; Michel Mayor; Dominique Naef; Francesco Pepe; Shay Zucker

doi:10.1051/0004-6361/201015427

arXiv · 1009.5991

Search for brown-dwarf companions of stars

Johannes Sahlmann·Damien Segransan·Didier Queloz·Stephane Udry·Nuno C. Santos·Maxime Marmier·Michel Mayor·Dominique Naef·Francesco Pepe·Shay Zucker

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Abstract

The discovery of 9 new brown-dwarf candidates orbiting stars in the CORALIE and HARPS radial-velocity surveys is reported. New CORALIE radial velocities yielding accurate orbits of 6 previously-known hosts of potential brown-dwarf companions are presented. Including targets selected from the literature, 33 hosts of potential brown-dwarf companions are examined. Employing innovative methods, we use the new reduction of the Hipparcos data to fully characterise the astrometric orbits of 6 objects, revealing M-dwarf companions with masses between 90 M_Jup and 0.52 M_Sun. Additionally, the masses of two companions can be restricted to the stellar domain. The companion to HD 137510 is found to be a brown dwarf. At 95 % confidence, the companion of HD 190228 is also a brown dwarf. The remaining 23 companions persist as brown-dwarf candidates. Based on the CORALIE planet-search sample, we obtain an upper limit of 0.6 % for the frequency of brown-dwarf companions around Sun-like stars. We find that the companion-mass distribution function is rising at the lower end of the brown-dwarf mass range, suggesting that in fact we are detecting the high-mass tail of the planetary distribution.

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Johannes Sahlmann, Damien Segransan, Didier Queloz, Stephane Udry, Nuno C. Santos, Maxime Marmier, Michel Mayor, Dominique Naef, Francesco Pepe, Shay Zucker. 2010-09-29. Search for brown-dwarf companions of stars. https://doi.org/10.1051/0004-6361/201015427

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