http://arxiv.org/abs/1910.07835
The first planetary candidate discovered with radial velocities around a solar-like star other than the Sun, HD 114762 b, by Latham et al. (1989) was detected with a minimum mass of 11 Mjup. The small v sin(i)~0 km/s otherwise measured by spectral analysis led to suspect that this companion of a late-F sub-giant star better correspond to a massive brown dwarf (BD), or even a low-mass M-dwarf nearly face-on. To our knowledge, the nature of HD 114762 b is still undetermined. Thanks to the first data release DR1 of the Gaia mission, the astrometric noise measured for this system allows us to derive new constraints on the astrometric motion of HD 114762 and on the mass of its companion. We use a method, GASTON, introduced in a preceding paper, able to simulate Gaia data and finding the distribution of inclinations compatible with the astrometric excess noise. With an inclination of 6.23(+1.93)(-1.25) degrees, the mass of the companion is constrained to M_b=107(+31)(-27) Mjup. HD 114762 b thus belong indeed to the M dwarf domain, down to brown dwarfs, with M_b>13.5 Mjup at the 3-sigma level, and is actually not a planet.
F. Kiefer
Fri, 18 Oct 19
48/77
Comments: 4 figure, 4 tables, submitted to A&A on 17/10/2019