Stellar-activity analysis of the nearby M dwarf GJ 526: Multi-dimensional Gaussian-process modelling of RV, FWHM, and S-index

Bibcode
2025A&A...703A.245S
DOI
10.1051/0004-6361/202556346
Stefanov, A. K.; González Hernández, J. I.; Suárez Mascareño, A.; Rebolo, R.; Nari, N.; Mestre, J. M.; Sousa, S. G.; Tabernero, H. M.; Zapatero Osorio, M.-R.; Figueira, P.; Faria, J. P.; Hobson, M. J.; Silva, A. M.; Castro-González, A.; Santos, N. C.; Sozzetti, A.; Pepe, F.; Cristiani, S.; Lavie, B.; Martins, C. J. A. P.
Bibliographical reference

Astronomy and Astrophysics

Advertised on:
11
2025
Journal
Astronomy and Astrophysics
Number of authors
20
IAC number of authors
5
Citations
0
Refereed citations
0
Description
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 used 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 carried out a joint modelling of (i) the stellar rotation in RV, full width at half maximum (FWHM), and Mount Wilson S-index through Gaussian processes; (ii) long-term trends in these three physical quantities; and (iii) RV planetary signals. We constrained the stellar-rotation period to Prot = 48.7 ± 0.3 d, and discovered a weak sinusoidal signature in RV, FWHM, and S-index of period Pcyc = 1680−40+50d. 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.
Type
Refereed
Techniques

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