摘要：We report the discovery of three new substellar companions to solar-type stars,
HD 191806, HD 214823, and HD 221585, based on radial velocity measurements obtained at the
Haute-Provence Observatory. Data from the SOPHIE spectrograph are combined with
observations acquired with its predecessor, ELODIE, to detect and characterise the orbital
parameters of three new gaseous giant and brown dwarf candidates. Additionally, we combine
SOPHIE data with velocities obtained at the Lick Observatory to improve the parameters of
an already known giant planet companion, HD 16175 b. Thanks to the use of different
instruments, the data sets of all four targets span more than ten years. Zero-point
offsets between instruments are dealt with using Bayesian priors to incorporate the
information we possess on the SOPHIE/ELODIE offset based on previous studies. The reported
companions have orbital periods between three and five years and minimum masses between
1.6 MJup and 19 MJup.
Additionally, we find that the star HD 191806 is experiencing a secular acceleration of
over 11 m s-1 per
year, potentially due to an additional stellar or substellar companion. A search for the
astrometric signature of these companions was carried out using Hipparcos data.
No orbit was detected, but a significant upper limit to the companion mass can be set for
HD 221585, whose companion must be substellar. With the exception of HD 191806 b, the
companions are located within the habitable zone of their host star. Therefore, satellites
orbiting these objects could be a propitious place for life to develop.
关键词：planetary systems;techniques: radial velocities;stars: individual: HD 221585;stars: individual: HD 16175;stars: individual: HD 191806;stars: individual: HD 214823
