Bibcode
Pinamonti, M.; Sozzetti, A.; Giacobbe, P.; Damasso, M.; Scandariato, G.; Perger, M.; González Hernández, J. I.; Lanza, A. F.; Maldonado, J.; Micela, G.; Suárez Mascareño, A.; Toledo-Padrón, B.; Affer, L.; Benatti, S.; Bignamini, A.; Bonomo, A. S.; Claudi, R.; Cosentino, R.; Desidera, S.; Maggio, A.; Martinez Fiorenzano, A.; Pagano, I.; Piotto, G.; Rainer, M.; Rebolo, R.; Ribas, I.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 625, id.A126, 17 pp.
Fecha de publicación:
5
2019
Revista
Número de citas
14
Número de citas referidas
14
Descripción
Context. Small rocky planets seem to be very abundant around low-mass
M-type stars. Their actual planetary population is however not yet
precisely understood. Currently, several surveys aim to expand the
statistics with intensive detection campaigns, both photometric and
spectroscopic. Aims: The HADES program aims to improve the
current statistics through the in-depth analysis of accurate
radial-velocity (RV) monitoring in a narrow range of spectral sub-types,
with the precision needed to detect small planets with a few Earth
masses. Methods: We analyse 106 spectroscopic HARPS-N
observations of the active M0-type star GJ 685 taken over the past five
years. We combine these data with photometric measurements from
different observatories to accurately model the stellar rotation and
disentangle its signals from genuine Doppler planetary signals in the RV
data. We run an MCMC analysis on the RV and activity index time series
to model the planetary and stellar signals present in the data, applying
Gaussian Process regression technique to deal with the stellar activity
signals. Results: We identify three periodic signals in the RV
time series, with periods of 9, 24, and 18 d. Combining the analyses of
the photometry of the star with the activity indexes derived from the
HARPS-N spectra, we identify the 18 d and 9 d signals as
activity-related, corresponding to the stellar rotation period and its
first harmonic, respectively. The 24 d signal shows no relation to any
activity proxy, and therefore we identify it as a genuine planetary
signal. We find the best-fit model describing the Doppler signal of the
newly found planet, GJ 685 b, corresponding to an orbital period
Pb = 24.160-0.047+0.061 d and a minimum
mass MP sin i = 9.0-1.8+1.7
M⊕. We also study a sample of 70 RV-detected M-dwarf
planets, and present new statistical evidence of a difference in mass
distribution between the populations of single- and multi-planet
systems, which can shed new light on the formation mechanisms of
low-mass planets around late-type stars.
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 APACHE array located at the Astronomical
Observatory of the Aosta Valley; photometric observations made with the
robotic telescope APT2 (within the EXORAP programme) located at Serra La
Nave on Mt. Etna.
Proyectos relacionados
ARES: Alta Resolución ESpectral
ARES (Alta Resolución ESpectral) es un proyecto coordinado que pretende unificar y consolidar el esfuerzo del IAC en la investigación de alta resolución espectral, impulsando programas científicos frontera que el IAC desarrolla en el ámbito de exoplanetas, poblaciones estelares y cosmología, usando espectroscopía ultraestable de alta resolución.
Jonay Isai
González Hernández