ICATE   21876
INSTITUTO DE CIENCIAS ASTRONOMICAS, DE LA TIERRA Y DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
zeta1+zeta2 Reticuli binary system: a puzzling chromospheric activity pattern
Autor/es:
BUCCINO, A; NUÑEZ, N E; FLORES, M; JAQUE ARANCIBIA, M; JOFRÉ, E; SAFFE, C; GONZÁLEZ, J F
Revista:
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2018 vol. 476 p. 2751 - 2759
ISSN:
0035-8711
Resumen:
We perform, for the first time, a detailed long-term activity study ofthe binary system ζ Ret. We use all available HARPS spectraobtained between the years 2003 and 2016. We build a time series of theMount Wilson S index for both stars, then we analyse these series byusing Lomb-Scargle periodograms. The components ζ1 Retand ζ2 Ret that belong to this binary system arephysically very similar to each other and also similar to our Sun, whichmakes it a remarkable system. We detect in the solar-analogue starζ2 Ret a long-term activity cycle with a period of ~10 yr, similar to the solar one (~11 yr). It is worthwhileto mention that this object satisfies previous criteria for a flat starand for a cycling star simultaneously. Another interesting feature ofthis binary system is a high ~0.220 dex difference between theaverage log (R´_HK) activity levels of both stars. Our study clearlyshows that ζ1 Ret is significantly more active thanζ2 Ret. In addition, ζ1 Ret shows anerratic variability in its stellar activity. In this work, we exploredifferent scenarios trying to explain this rare behaviour in a pair ofcoeval stars, which could help to explain the difference in this andother binary systems. From these results, we also warn that for thedevelopment of activity-age calibrations (which commonly use binarysystems and/or stellar clusters as calibrators) the whole history ofactivity available for the stars involved should be taken into account.