Detalles de publicación
PP 025080
Stellar-activity analysis of the nearby M dwarf GJ 526. Multi-dimensional Gaussian-process modelling of RV, FWHM and S-index
(1) Instituto de Astrofísica de Canarias, (2) Departamento de Astrofísica, Universidad de La Laguna, (3) Consejo Superior de Investigaciones Científicas,
(4) Light Bridges S. L., (5) Dipartimento di Fisica e Astronomia "Galileo Galilei", Universitá di Padova, (6) Instituto de Astrofísica e Ciências do Espaço, CAUP, Universidade do Porto, (7) Departamento de Física de la Tierra y Astrofísica & IPARCOS-UCM, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, (8) Centro de Astrobiología (CAB), CSIC-INTA, (9) Observatoire Astronomique de l’Université de Genève, (10) Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, (11) INAF - Osservatorio Astrofisico di Torino, (12) INAF - Osservatorio Astrofisico di Trieste, (13) IFPU - Institute for Fundamental Physics of the Universe, (14) Centro de Astrofísica da Universidade do Porto
M dwarfs are the most abundant stars in the Galaxy, and their low masses make them natural favourites for exoplanet radial-velocity (RV) searches. Nevertheless, these stars often demonstrate strong stellar activity that is yet to be fully understood. We use high-precision ESPRESSO, HIRES, and HARPS spectroscopy to perform a stellar-activity analysis on the nearby early M dwarf GJ 526 (d=5.4 pc). We carry out joint modelling of: (i) stellar rotation in RV, FWHM, and Mount Wilson S-index through Gaussian processes, (ii) long-term trends in these three physical quantities, (iii) RV planetary signals. We constrain the stellar-rotation period to P_rot=48.7±0.3 d, and discover a weak sinusoidal signature in RV, FWHM and S-index of period P_cyc=1680(+50,-40) d. We propose phase-space trajectories between RV and activity indicators as a novel means to visualise and interpret stellar activity. Current evidence does not support planetary companions of GJ 526.