Bibcode
Pinamonti, M.; Damasso, M.; Marzari, F.; Sozzetti, A.; Desidera, S.; Maldonado, J.; Scandariato, G.; Affer, L.; Lanza, A. F.; Bignamini, A.; Bonomo, A. S.; Borsa, F.; Claudi, R.; Cosentino, R.; Giacobbe, P.; González-Álvarez, E.; González Hernández, J. I.; Gratton, R.; Leto, G.; Malavolta, L.; Martinez Fiorenzano, A.; Micela, G.; Molinari, E.; Pagano, I.; Pedani, M.; Perger, M.; Piotto, G.; Rebolo, R.; Ribas, I.; Suárez Mascareño, A.; Toledo-Padrón, B.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 617, id.A104, 17 pp.
Fecha de publicación:
9
2018
Revista
Número de citas
34
Número de citas referidas
31
Descripción
We present 20 yr of radial velocity (RV) measurements of the M1 dwarf
Gl15A, combining five years of intensive RV monitoring with the HARPS-N
spectrograph with 15 yr of archival HIRES/Keck RV data. We have carried
out an MCMC-based analysis of the RV time series, inclusive of Gaussian
Process (GP) approach to the description of stellar activity induced RV
variations. Our analysis confirms the Keplerian nature and refines the
orbital solution for the 11.44-day period super Earth, Gl15A b, reducing
its amplitude to 1.68-0.18+0.17 m s-1
(M sin i = 3.03-0.44+0.46 M⊕),
and successfully models a long-term trend in the combined RV dataset in
terms of a Keplerian orbit with a period around 7600 days and an
amplitude of 2.5-1.0+1.3 m s-1,
corresponding to a super-Neptune mass (M sin i =
36-18+25 M⊕) planetary companion.
We also discuss the present orbital configuration of Gl15A planetary
system in terms of the possible outcomes of Lidov-Kozai interactions
with the wide-separation companion Gl15B in a suite of detailed
numerical simulations. In order to improve the results of the dynamical
analysis, we have derived a new orbital solution for the binary system,
combining our RV measurements with astrometric data from the WDS
catalogue. The eccentric Lidov-Kozai analysis shows the strong influence
of Gl15B on the Gl15A planetary system, which can produce orbits
compatible with the observed configuration for initial inclinations of
the planetary system between 75° and 90°, and can also enhance
the eccentricity of the outer planet well above the observed value, even
resulting in orbital instability, for inclinations around 0° and
15°-30°. The Gl15A system is the multi-planet system closest to
Earth, at 3.56 pc, and hosts the longest period RV sub-Jovian mass
planet discovered so far. Its orbital architecture constitutes a very
important laboratory for the investigation of formation and orbital
evolution scenarios for planetary systems in binary stellar systems.
Based on observations made with the Italian Telescopio Nazionale Galileo
(TNG), operated on the island of La Palma by the INAF - Fundación
Galileo Galilei at the Roche de Los Muchachos Observatory of the
Instituto de Astrofísica de Canarias (IAC); photometric
observations made with the robotic telescope APT2 (within the EXORAP
programme) located at Serra La Nave on Mt. Etna.